RELATED APPLICATION
FIELD OF THE DISCLOSURE
[0002] Embodiments disclosed herein are related to wireless communication; more particularly,
embodiments disclosed herein relate to a multi-band metasurface ESA, such as can be
used, for example, in a satellite terminal.
BACKGROUND
[0003] Metasurface antennas have recently emerged as a new technology for generating steered,
directive beams from a lightweight, low-cost, and planar physical platform. Such metasurface
antennas have been recently used in a number of applications, such as, for example,
satellite communication. These antennas can have radio-frequency (RF) radiating antenna
elements and are electrically scanned to perform transmit (Tx) and receive (Rx) operations.
[0004] Satellite antennas used in satellite terminals are typically designed for operation
at one frequency band. Well-known examples of some such frequency bands include Ka
and Ku frequency bands. Metasurface antennas and antennas with traditional phased
arrays antennas have been designed to operate at either the Ka and Ku bands, as well
as other frequency bands. However, if there is a need to communicate at multiple bands
(e.g., both Ka and Ku bands), then solutions are limited. For example, to support
communication at both multiple bands using traditional phased arrays, multiple flat
panel apertures designed to operate at different frequency bands would have to be
configured side-by-side in order to support operation using multiple bands.
SUMMARY
[0005] Shared aperture multi-band antennas (e.g., metasurface electronically scanned antennas
(ESAs), etc.) are described. In some embodiments, an antenna includes an aperture
having a plurality of multi-band radio-frequency (RF) radiating antenna elements,
wherein each antenna element of the plurality of multi-band RF radiating antenna elements
is configurable to operate at any of multiple bands. In some embodiments, the antenna
also includes a controller coupled to the plurality of antenna elements to dynamically
configure said each antenna element of the plurality of antenna elements to operate
at each of the multiple bands at different times.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The described embodiments and the advantages thereof may best be understood by reference
to the following description taken in conjunction with the accompanying drawings.
These drawings in no way limit any changes in form and detail that may be made to
the described embodiments by one skilled in the art without departing from the spirit
and scope of the described embodiments.
Figure 1 illustrates an exploded view of some embodiments of a flat-panel antenna.
Figure 2 illustrates an example of a communication system that includes one or more antennas
described herein.
Figure 3A illustrates some embodiments of a Ka/Ku quadband metasurface.
Figure 3B illustrates some embodiments of a metasurface with dual-band radiating elements.
Figure 4 illustrates some embodiments of dual-band radiating elements utilizing first and
second resonances of the slot to achieve dual-band operation.
Figure 5A illustrates some embodiment of dual-band radiating elements with a die integrating
both Ka and Ku tunable components for half-duplex operation.
Figure 5B illustrates some embodiment of dual-band radiating elements with a die integrating
both Ka and Ku tunable components for full-duplex operation.
Figures 6A and 6B illustrate some embodiments of dual-band radiating elements with two integrated circuit
dies for (A) half-duplex and (B) full-duplex operation, respectively.
Figure 7 illustrates some embodiments of a process for controlling an RF radiating antenna
element.
DETAILED DESCRIPTION
[0007] In the following description, numerous details are set forth to provide a more thorough
explanation of embodiments of the present disclosure. It will be apparent, however,
to one skilled in the art, that the teachings disclosed herein may be practiced without
these specific details. In other instances, well-known structures and devices are
shown in block diagram form, rather than in detail, in order to avoid obscuring the
present disclosure.
[0008] Embodiments described herein relate to metasurface electronically steered antennas
(ESAs) that have a single aperture with antenna elements that can be configured for
use at multiple frequency bands. That is, a single aperture integrates antenna elements
that are configurable to operate at one of multiple frequency bands at any one time.
In some embodiments, the antenna elements are radio-frequency (RF) radiating antenna
elements that operate at multiple bands (e.g., Ku and Ka bands). The multiple bands
can be transmit (Tx) and receive (Rx) bands. In some embodiments, multiple receive
(Rx) and transmit (Tx) bands include Ka and Ku receive (Rx) and transmit (Tx) bands.
[0009] Shared-aperture multi-band mobile user satellite terminals that operate at both Ku/Ka
bands are highly desired for both commercial and government applications. Combining
Ku/Ka Rx and Tx bands into a single physical aperture is currently not feasible with
traditional phased array architectures. This is due to at least two key challenges:
(1) space available for beamforming ICs is limited due to array density, and also
(2) power requirements cannot meet size, weight, power, and cost (SWaP-C) requirements
for mobile user terminals. A single shared aperture solution will have a significant
advantage in terms of cost and size.
[0010] The following disclosure discusses examples of antenna apparatus embodiments followed
by details of shared aperture embodiments.
Examples of Antenna Embodiments
[0011] The techniques described herein may be used with a variety of flat panel satellite
antennas. Embodiments of such flat panel antennas are disclosed herein. In some embodiments,
the flat panel satellite antennas are part of a satellite terminal. The flat panel
antennas include one or more arrays of antenna elements on an antenna aperture.
[0012] In some embodiments, the antenna aperture is a metasurface antenna aperture, such
as, for example, the antenna apertures described below. In some embodiments, the antenna
elements comprise radio-frequency (RF) radiating antenna elements. In some embodiments,
the antenna elements include tunable devices to tune the antenna elements. Examples
of such tunable devices include diodes and varactors such as, for example, described
in
U.S. Patent No. 11,489,266, entitled "Metasurface Antennas Manufactured with Mass
Transfer Technologies," issued November 1, 2022. In some other embodiments, the antenna elements comprise liquid crystal (LC)-based
antenna elements, such as, for example, those disclosed in
U.S. Patent No. 9,887,456, entitled "Dynamic Polarization and Coupling Control from
a Steerable Cylindrically Fed Holographic Antenna", issued February 6, 2018, or other RF radiating antenna elements. It should be appreciated that other tunable
devices such as, for example, but not limited to, tunable capacitors, tunable capacitance
dies, packaged dies, micro-electromechanical systems (MEMS) devices, or other tunable
capacitance devices, could be placed into an antenna aperture or elsewhere in variations
on the embodiments described herein.
[0013] In some embodiments, the antenna aperture having the one or more arrays of antenna
elements is comprised of multiple segments that are coupled together. In some embodiments,
when coupled together, the combination of the segments form groups of antenna elements
(e.g., closed concentric rings of antenna elements concentric with respect to the
antenna feed, etc.). For more information on antenna segments, see
U.S. patent no. 9,887,455, entitled "Aperture Segmentation of a Cylindrical Feed Antenna",
issued February 6, 2018.
[0014] Figure 1 illustrates an exploded view of some embodiments of a flat-panel antenna.
Referring to Figure 1, antenna 100 comprises a radome 101, a core antenna 102, antenna
support plate 103, antenna control unit (ACU) 104, a power supply unit 105, terminal
enclosure platform 106, comm (communication) module 107, and RF chain 108.
[0015] Radome 101 is the top portion of an enclosure that encloses core antenna 102. In
some embodiments, radome 101 is weatherproof and is constructed of material transparent
to radio waves to enable beams generated by core antenna 102 to extend to the exterior
of radome 101.
[0016] In some embodiments, core antenna 102 comprises an aperture having RF radiating antenna
elements. These antenna elements act as radiators (or slot radiators). In some embodiments,
the antenna elements comprise scattering metamaterial antenna elements. In some embodiments,
the antenna elements comprise both Receive (Rx) and Transmit (Tx) irises, or slots,
that are interleaved and distributed on the whole surface of the antenna aperture
of core antenna 102. Such Rx and Tx irises may be in groups of two or more sets where
each set is for a separately and simultaneously controlled band. Examples of such
antenna elements with irises are described in
U.S. Patent No. 10,892,553, entitled "Broad Tunable Bandwidth Radial Line Slot Antenna",
issued January 12, 2021.
[0017] In some embodiments, the antenna elements comprise irises (iris openings) and the
aperture antenna is used to generate a main beam shaped by using excitation from a
cylindrical feed wave for radiating the iris openings through tunable elements (e.g.,
diodes, varactors, patch, etc.). In some embodiments, the antenna elements can be
excited to radiate a horizontally or vertically polarized electric field at desired
scan angles.
[0018] In some embodiments, a tunable element (e.g., diode, varactor, patch etc.) is located
over each iris slot. The amount of radiated power from each antenna element is controlled
by applying a voltage to the tunable element using a controller in ACU 104. Traces
in core antenna 102 to each tunable element are used to provide the voltage to the
tunable element. The voltage tunes or detunes the capacitance and thus the resonance
frequency of individual elements to effectuate beam forming. The voltage required
is dependent on the tunable element in use. Using this property, in some embodiments,
the tunable element (e.g., diode, varactor, LC, etc.) integrates an on/off switch
for the transmission of energy from a feed wave to the antenna element. When switched
on, an antenna element emits an electromagnetic wave like an electrically small dipole
antenna. Note that the teachings herein are not limited to having unit cell that operates
in a binary fashion with respect to energy transmission. For example, in some embodiments
in which varactors are the tunable element, there are 32 tuning levels. As another
example, in some embodiments in which LC is the tunable element, there are 16 tuning
levels.
[0019] A voltage between the tunable element and the slot can be modulated to tune the antenna
element (e.g., the tunable resonator/slot). Adjusting the voltage varies the capacitance
of a slot (e.g., the tunable resonator/slot). Accordingly, the reactance of a slot
(e.g., the tunable resonator/slot) can be varied by changing the capacitance. Resonant
frequency of the slot also changes according to the equation

where
f is the resonant frequency of the slot and L and C are the inductance and capacitance
of the slot, respectively. The resonant frequency of the slot affects the energy coupled
from a feed wave propagating through the waveguide to the antenna elements.
[0020] In particular, the generation of a focused beam by the metamaterial array of antenna
elements can be explained by the phenomenon of constructive and destructive interference,
which is well known in the art. Individual electromagnetic waves sum up (constructive
interference) if they have the same phase when they meet in free space to create a
beam, and waves cancel each other (destructive interference) if they are in opposite
phase when they meet in free space. If the slots in core antenna 102 are positioned
so that each successive slot is positioned at a different distance from the excitation
point of the feed wave, the scattered wave from that antenna element will have a different
phase than the scattered wave of the previous slot. In some embodiments, if the slots
are spaced one quarter of a wavelength apart, each slot will scatter a wave with a
one fourth phase delay from the previous slot. In some embodiments, by controlling
which antenna elements are turned on or off (i.e., by changing the pattern of which
antenna elements are turned on and which antenna elements are turned off) or which
of the multiple tuning levels is used, a different pattern of constructive and destructive
interference can be produced, and the antenna can change the direction of its beam(s).
[0021] In some embodiments, core antenna 102 includes a coaxial feed that is used to provide
a cylindrical wave feed via an input feed, such as, for example, described in
U.S. Patent No. 9,887,456, entitled "Dynamic Polarization and Coupling Control from
a Steerable Cylindrically Fed Holographic Antenna", issued February 6, 2018 or in
U.S. Patent No. 11,489,266, entitled "Metasurface Antennas Manufactured with Mass
Transfer Technologies," issued November 1, 2022. In some embodiments, the cylindrical wave feed feeds core antenna 102 from a central
point with an excitation that spreads outward in a cylindrical manner from the feed
point. In other words, the cylindrically fed wave is an outward travelling concentric
feed wave. Even so, the shape of the cylindrical feed antenna around the cylindrical
feed can be circular, square or any shape. In some other embodiments, a cylindrically
fed antenna aperture creates an inward travelling feed wave. In such a case, the feed
wave most naturally comes from a circular structure.
[0022] In some embodiments, the core antenna comprises multiple layers. These layers include
the one or more substrate layers forming the RF radiating antenna elements. In some
embodiments, these layers may also include impedance matching layers (e.g., a wide-angle
impedance matching (WAIM) layer, etc.), one or more spacer layers and/or dielectric
layers. Such layers are well-known in the art.
[0023] Antenna support plate 103 is coupled to core antenna 102 to provide support for core
antenna 102. In some embodiments, antenna support plate 103 includes one or more waveguides
and one or more antenna feeds to provide one or more feed waves to core antenna 102
for use by antenna elements of core antenna 102 to generate one or more beams.
[0024] ACU 104 is coupled to antenna support plate 103 and provides controls for antenna
100. In some embodiments, these controls include controls for drive electronics for
antenna 100 and a matrix drive circuitry to control a switching array interspersed
throughout the array of RF radiating antenna elements. In some embodiments, the matrix
drive circuitry uses unique addresses to apply voltages onto the tunable elements
of the antenna elements to drive each antenna element separately from the other antenna
elements. In some embodiments, the drive electronics for ACU 104 comprise commercial
off-the shelf LCD controls used in commercial television appliances that adjust the
voltage for each antenna element.
[0025] More specifically, in some embodiments, ACU 104 supplies an array of voltage signals
to the tunable devices of the antenna elements to create a modulation, or control,
pattern. The control pattern causes the elements to be tuned to different states.
In some embodiments, ACU 104 uses the control pattern to control which antenna elements
are turned on or off (or which of the tuning levels is used) and at which phase and
amplitude level at the frequency of operation. The elements are selectively detuned
for frequency operation by voltage application. In some embodiments, multistate control
is used in which various elements are turned on and off to varying levels, further
approximating a sinusoidal control pattern, as opposed to a square wave (i.e., a sinusoid
gray shade modulation pattern).
[0026] In some embodiments, ACU 104 also contains one or more processors executing the software
to perform some of the control operations. ACU 104 may control one or more sensors
(e.g., a GPS receiver, a three-axis compass, a 3-axis accelerometer, 3-axis gyro,
3-axis magnetometer, etc.) to provide location and orientation information to the
processor(s). The location and orientation information may be provided to the processor(s)
by other systems in the earth station and/or may not be part of the antenna system.
[0027] Antenna 100 also includes a comm (communication) module 107 and an RF chain 108.
Comm module 107 includes one or more modems enabling antenna 100 to communicate with
various satellites and/or cellular systems, in addition to a router that selects the
appropriate network route based on metrics (e.g., quality of service (QoS) metrics,
e.g., signal strength, latency, etc.). RF chain 108 converts analog RF signals to
digital form. In some embodiments, RF chain 108 comprises electronic components that
may include amplifiers, filters, mixers, attenuators, and detectors.
[0028] Antenna 100 also includes power supply unit 105 to provide power to various subsystems
or parts of antenna 100.
[0029] Antenna 100 also includes terminal enclosure platform 106 that forms the enclosure
for the bottom of antenna 100. In some embodiments, terminal enclosure platform 106
comprises multiple parts that are coupled to other parts of antenna 100, including
radome 101, to enclose core antenna 102.
[0030] Figure 2 illustrates an example of a communication system that includes one or more
antennas described herein. Referring to Figure 2, vehicle 200 includes an antenna
201. In some embodiments, antenna 201 comprises antenna 100 of Figure 1.
[0031] In some embodiments, vehicle 200 may comprise any one of several vehicles, such as,
for example, but not limited to, an automobile (e.g., car, truck, bus, etc.), a maritime
vehicle (e.g., boat, ship, etc.), airplanes (e.g., passenger jets, military jets,
small craft planes, etc.), etc. Antenna 201 may be used to communicate while vehicle
200 is either on-the-pause, or moving. Antenna 201 may be used to communicate to fixed
locations as well, e.g., remote industrial sites (mining, oil, and gas) and/or remote
renewable energy sites (solar farms, windfarms, etc.).
[0032] In some embodiments, antenna 201 is able to communicate with one or more communication
infrastructures (e.g., satellite, cellular, networks (e.g., the Internet), etc.).
For example, in some embodiments, antenna 201 is able to communicate with satellites
220 (e.g., a GEO satellite) and 221 (e.g., a LEO satellite), cellular network 230
(e.g., an LTE, etc.), as well as network infrastructures (e.g., edge routers, Internet,
etc.). For example, in some embodiments, antenna 201 comprises one or more satellite
modems (e.g., a GEO modem, a LEO modem, etc.) to enable communication with various
satellites such as satellite 220 (e.g., a GEO satellite) and satellite 221 (e.g.,
a LEO satellite) and one or more cellular modems to communicate with cellular network
230. For another example of an antenna communicating with one or more communication
infrastructures, see
U.S. Patent Serial No. 16/750,439, entitled "Multiple Aspects of Communication in
a Diverse Communication Network", and filed January 23, 2020.
[0033] In some embodiments, to facilitate communication with various satellites, antenna
201 performs dynamic beam steering. In such a case, antenna 201 is able to dynamically
change the direction of a beam that it generates to facilitate communication with
different satellites. In some embodiments, antenna 201 includes multi-beam beam steering
that allows antenna 201 to generate two or more beams at the same time, thereby enabling
antenna 201 to communication with more than one satellite at the same time. Such functionality
is often used when switching between satellites (e.g., performing a handover). For
example, in some embodiments, antenna 201 generates and uses a first beam for communicating
with satellite 220 and generates a second beam simultaneously to establish communication
with satellite 221. After establishing communication with satellite 221, antenna 201
stops generating the first beam to end communication with satellite 220 while switching
over to communicate with satellite 221 using the second beam. For more information
on multi-beam communication, see
U.S. Patent No. 11,063,661, entitled "Beam Splitting Hand Off Systems Architecture",
issued July 13, 2021.
[0034] In some embodiments, antenna 201 uses path diversity to enable a communication session
that is occurring with one communication path (e.g., satellite, cellular, etc.) to
continue during and after a handover with another communication path (e.g., a different
satellite, a different cellular system, etc.). For example, if antenna 201 is in communication
with satellite 220 and switches to satellite 221 by dynamically changing its beam
direction, its session with satellite 220 is combined with the session occurring with
satellite 221.
[0035] Thus, the antennas described herein may be part of a satellite terminal that enables
ubiquitous communications and multiple different communication connections.
[0036] In some embodiments, antenna 201 comprises a metasurface RF antenna having multiple
RF radiating antenna elements that are tuned to desired frequencies using RF antenna
element drive circuitry. The drive circuitry can include a drive transistor (e.g.,
a thin film transistor (TFT ) (e.g., CMOS, NMOS, etc.), low or high temperature polysilicon
transistor, memristor, etc.), a Microelectromechanical systems (MEMS) circuit, or
other circuit for driving a voltage to an RF radiating antenna element. In some embodiments,
the drive circuitry comprises an active-matrix drive. In some embodiments, the frequency
of each antenna element is controlled by an applied voltage. In some embodiments,
this applied voltage is also stored in each antenna element (pixel circuit) until
the next voltage writing cycle.
Embodiments of Antennas with Shared Apertures
[0037] Antenna embodiments are disclosed here that integrate multiple receive (Rx) and transmit
(Tx) frequency bands (e.g., Ka/Ku Rx and Ka/Ku Tx bands) into a shared aperture metasurface
ESA. In some embodiments, the integration relies on two concepts: (1) interleaving
sub-arrays of radiating antenna elements in a single metasurface to achieve shared
aperture operation, and (2) loading radiating elements with integrated varactor circuits
(or other tunable components) to control the resonances and to allow multi-band operation
of radiating antenna elements.
[0038] Figure 3A shows some embodiments of a Ku/Ka dual-band metasurface where the shared
aperture capability is achieved by interleaving subarrays of Ku/Ka (dual-band) Rx
and Tx radiating antenna elements. Referring to Figure 3A, metasurface 301 includes
groups of RF radiating antenna elements. In some embodiments, each group of RF radiating
antenna elements includes a Ka Tx radiating antenna element, such as Ka Tx radiating
element 310, a Ka Rx radiating antenna element, such as Ka Rx radiating element 311,
a Ku Tx radiating antenna element, such as Ku Tx radiating element 312, and a Ku Rx
radiating antenna element, such as Ku Rx radiating element 313.
[0039] The implementation of a Ku/Ka dual-band metasurface according to Figure 3A can have
challenges due to the density requirements of Ka band and large frequency separation
between Ka and Ku bands. To be more specific, the Ka aperture may require a metasurface
with a high density that may not allow for placing and fitting Ku radiating elements
with required efficiency. For example, in some implementations, the spacing between
Ka band elements is 0.08in while the spacing between Ka band elements is 0.16in, or
twice as much. Thus, in some embodiments, an aperture combining these two bands uses
the smaller of these distances, which is not efficient. Furthermore, the slot (iris)
sizes for different bands (e.g., Ku band slots are much larger than Ku band slots)
also makes integrating them together difficult. Moreover, when adding several sub-arrays
into a single aperture, fitting the integrated circuits (ICs) and/or circuitry for
driving those elements into the aperture is also considered and is difficult with
the size of the elements and the distances between them.
[0040] To mitigate these challenges, in some embodiments, the antenna aperture includes
and uses multi-band radiating antenna elements that can be dynamically configured
to operate at one of multiple frequency bands. In some embodiments, the antenna aperture
includes and uses dual-band radiating antenna elements that operate at more than one
or multiple bands, for example, in some embodiments, at two, or dual, frequency bands
(e.g., both Ku and Ka bands). Figure 3B illustrates some embodiments of an implementation
of shared aperture metasurface ESA where the Ku/Ka bands share the same Rx and Tx
radiating elements. Referring to Figure 3B, metasurface 320 includes many RF radiating
antenna elements, and each of the RF antenna elements can be configured to operate
in either of the Ku or Ka bands. For example, Ku/Ka Tx RF radiating antenna element
321 can be configured at any time to operate either at the Ku band or Ka band for
Tx operation, while Ku/Ka Rx RF radiating antenna element 322 can be configured at
any time to operate either at the Ku band or Ka band for Rx operation. In the following
description, several embodiments of dual-band radiating antenna elements are described.
[0041] Figure 4 shows some embodiments of a dual-band radiating antenna element. Referring
to Figure 4, in some embodiments, RF radiating antenna element 401 comprises slot
(iris) 402 that is loaded with two dies 403 and 404. In some embodiments, dies 403
and 404 are coupled across the width of the slot to pads on each side of slot 402.
In some embodiments, dies 403 and 404 are integrated circuits (ICs) and may include
varactor diodes (or other tunable devices) and other additional components (e.g.,
capacitors, other components described in more detail below). The tunable device acts
as described above and its operation is well-known to those skilled in the art.
[0042] The dual band operation is achieved by using the first and second resonances of each
antenna element, such as RF radiating antenna element 401, and independent control
of each resonance is enabled by choosing the location of the tunable component. The
resonances associated with dies 403 and 404 are shown as 2
nd Mode and 1
st Mode, respectively, in Figure 4.
[0043] More specifically, the operation of radiating antenna elements, such as radiating
antenna element 401, can be explained by the voltage distribution of the first and
second resonances of slot 402. At the center of slot 402 where die 404 is coupled
across its width, the voltage is maximum (410) in the first resonance while it is
zero (411) at the second resonance. This means that by loading the tunable component
in die 404 at the center, the first resonance can be tuned without impacting the second
resonance (since it is at zero at the point). On the other hand, if the tunable component
is placed at the edge of antenna element 401, such as the tunable component in die
403, it mostly affects the second resonance. In this case, the impact on first resonance
is small due to the smaller electric distribution. As shown in Figure 4, the voltage
in the first resonance (412) is much smaller than the voltage in the second resonance
(413), and therefore the influence of die 404 is much less than die 403 in the second
mode.
[0044] In some embodiments, the two dies are placed in positions where the mode of the other
one is a zero, or null. Therefore, in such embodiments, placements of the dies may
not be exactly at the center or at the very edge, but are placed based on where they
produce nulls or have very little influence on the resonance for the antenna element
at the other band. Note also in some embodiments, the die positioned near the edge
is placed as close, proximate, or adjacent to the edge as possible without creating
a short circuit across slot 402.
[0045] In some embodiments, the position of the dies as described above, with one at the
center and one near the edge, enables independent control of the two modes. In some
embodiments, the die near the edge is located at a distance from the edge of the end
of the slot that is approximately one-tenth (10%) the length of the slot. For example,
if the length of the slot is 2500 microns, the die can be located 200-250 microns
from the edge at the end of the slot. In some other embodiments, the position of the
dies may not be in the center and near the edge but are still offset with respect
to each other. Such an arrangement may impact their independent control as they may
tune together. Note that the placement of the dies for Tx and Rx antenna elements
can be different in some embodiments.
[0046] In some embodiments, control of the resonances of the antenna elements is performed
using controller 430. In some embodiments, controller 430 is, or is part of, the antenna
control unit (ACU) of the satellite antenna as described above and/or the terminal
of which it is part. Such a controller can be included to control other embodiments
of antenna elements described herein.
[0047] Figures 5A and 5B show some other embodiments of a dual-band radiating antenna element.
Referring to Figures 5A and 5B, dual-band radiating antenna element 500 comprises
a slot 501 that is loaded with a die 502. Die 502 is coupled across the width of slot
501 to pads on both sides of slot 501. In some embodiments, die 502 is an IC that
includes a tuning element. In some embodiments, die 502 also comprises two signal
paths, one for low frequency operation of dual-band radiating antenna element 500,
referred to herein as the low frequency path, and one for high frequency operation
of dual-band radiating antenna element 500, referred to herein as the high frequency
path. In some embodiments, the low frequency path is used and corresponds to the Ku
frequency band, while the high frequency path is used and corresponds to the Ka frequency
band.
[0048] As shown in Figure 5A, in some embodiments of a half-duplex design, each path comprises
a switch (e.g., MEMS switch, etc.) and a tunable component (e.g., varactor diode,
MEMS-based tunable capacitor, etc.). For example, low frequency path 510 includes
switch 521 and a tuning component 531, while high frequency path 511 includes switch
522 and a tuning component 532. When operating antenna element 500 at the lower band
(e.g., Ku band), switch 521 in low frequency path 510 is closed and switch 522 in
high frequency path 511 is open, thereby causing high frequency path 511 in die 502
and its tuning component 532 to have no (or little) influence on operation of slot
501 during low frequency operation. When operating antenna element 500 at the higher
frequency band (e.g., Ka band), switch 522 in high frequency path 511 is closed and
switch 521 in low frequency path 510 is open, thereby causing low frequency path 510
in die 502, and its tuning component 531, to have no (or little) influence on operation
of slot 501 during high frequency operation. In some embodiments, the opening and
closing of switches is performed by the ACU, which is also controlling the tunable
components.
[0049] As shown in Figure 5B, in some embodiments of a full-duplex design, switches 521
and 522 are replaced with low-pass and high pass filters, with filter 541 at low frequency
path 512 being a high pass filter and filter 542 at high frequency path 513 being
a low pass filter. During operation, each path is in use if the frequency band of
operation is in the passband of the filter. Filters 541 and 542 do not share the same
pass band, so the pass band of filter 541 is within the top band of filter 542 and
vice versa. If the band of operation is in the passband of filter 541, then the low
frequency path is "closed". Since the band of operation is in the stop band of filter
542, the high frequency path will be "open". In some embodiments, the filter characteristics
are selected to minimize loss and maximize isolation. In some embodiments, these filter
characteristics include the order of the filter and the filter type. For higher isolation
between the two bands, higher order filters can be used. As for filter types, there
are many well-known filters (e.g., Butterworth, Chebyshev, Bessel, etc.) that may
be used.
[0050] Figures 6A and 6B show some other embodiments of a dual-band radiating antenna element.
Referring to Figures 6A and 6B, the dual-band radiating antenna element 600 comprises
a slot 601 loaded with two dies 602 and 603. In some embodiments, each die provides
an independent control for one of the bands. For example, where dual-band radiating
antenna element 600 can be operated in Ku and Ka bands, one of dies 602 and 603 controls
dual-band radiating antenna element 600 for Ku band operation, while the other of
dies 602 and 603 controls dual-band radiating antenna element 600 for Ka band operation.
[0051] Figure 6A illustrates some embodiments of low-frequency and high-frequency dies for
a half-duplex operation mode. In this case, low frequency die 603 is placed at and
coupled across the width of slot 601 at the center of slot 601 (or substantially near
the center of slot 601) to pads on each side of slot 601, and high frequency die 602
is coupled across the width slot 601 to pads on each side of slot 601 and is placed
with an offset with respect to placement of low frequency die 603. In some embodiments,
low frequency die 603 comprises a tunable component 632 (e.g., a varactor diode, etc.)
coupled in parallel with a switch 631, and high frequency die 602 comprises a tunable
component 622 (e.g., a varactor diode, etc.) coupled in series with a switch 621.
[0052] When dual-band radiating antenna element 600 is operating at the low frequency band,
both switches 621 and 631 are open. When both switches 621 and 631 are open, the tunable
element 632 (e.g., a varactor) of low frequency die 603 at the center is operational
but the other tunable element 622 will be open (as if nothing is positioned there).
When dual-band radiating antenna element 600 is operating at the high frequency band,
both switches 621 and 631 are closed, and slot 601 is short circuited at the center
(as if there is no tunable element (e.g., varactor) there, so the effective size of
the slot is cut in half. However, high frequency die 602 at the other location is
connected. This is beneficial for this application since the Ka frequency bands are
approximately twice the Ku frequency bands. In some embodiments, die 603 is placed
at the center of slot 601 while die 602 is placed between the center and edge of slot
601 (e.g., ¼ of the slot length away from the edge of slot 601). Note that in some
other embodiments, die 602 is placed at a distance from the end of slot 601 that is
approximately one-tenth the length of slot 601. Other locations can be used as long
as the influence of the die as to independently controlling resonances of slot 601
is minimal or null.
[0053] Figure 6B illustrates a similar embodiment to that of Figure 6A except for full-duplex
operation. In this mode, switches 621 and 631 of dies 602 and 603, respectively, are
replaced with high-pass filters. For example, in Figure 6B, high frequency die 602
includes high-pass filter 641 in series with tunable component 642, while low frequency
die 603 includes high-pass filter 651 coupled in parallel with tunable component 652.
The high frequency band of interest (Ka) falls within the pass band of the high pass
filter, and the low frequency band of interest (Ku) falls within the stop band of
the filter. These filters could have similar characteristics. Therefore, if the signal
is within the passband of the filters, high frequency die 602 is operational, and
low frequency die 603 is short circuited; if the signal is within the stop band of
the filters, low frequency die 603 is operational, and high frequency die 602 is open.
[0054] Figure 7 illustrates some embodiments of a process for controlling an RF radiating
antenna element. In some embodiments, such an RF radiating antenna element can comprise
a multi-band antenna element. In some other embodiments, such an RF radiating antenna
element can comprise a multi-band antenna element.
[0055] Referring to Figure 7, the process begins by providing an aperture having multi-band
radio-frequency (RF) radiating antenna elements (701). In some embodiments, each antenna
element is configurable to operate at multiple frequency bands one at a time. In some
embodiments, the multi-band RF radiating antenna elements are dual-band RF radiating
antenna elements and can be configured to operate at either of the two bands. In some
embodiments, the two bands comprise the Ka and Ku bands. Note that in some other embodiments,
the antenna elements are configured to operate at other frequency bands.
[0056] Next, a set of one or more of the multi-band RF radiating antenna elements are configured
to operate at a first band (e.g., Ka, Ku, etc.) at a first time by controlling resonances
of a slot of each multi-band RF radiating antenna element in the set (702). This results
in obtaining operation of the set of multi-band RF radiating antenna elements at the
first band.
[0057] Subsequently, the set (or another set) of the multi-band RF radiating antenna elements
are configured to operate at a second band at a second time by controlling resonances
of a slot of each multi-band RF radiating antenna element in the set, where the first
and second bands are different (703). This results in obtaining operation of the set
of multi-band RF radiating antenna elements at the second band.
[0058] In some embodiments, the resonances of the antenna elements are controlled independently.
For example, in the case that the antenna elements are dual-band RF radiating antenna
elements, the slots have first and second resonances that are independently controlled
to obtain operation of the plurality of multi-band RF radiating antenna elements at
one of either first and second frequency bands.
[0059] There are a number of example embodiments described herein.
[0060] Example 1 is an antenna comprising: an aperture having a plurality of multi-band
radio-frequency (RF) radiating antenna elements, wherein each antenna element of the
plurality of multi-band RF radiating antenna elements is configurable to operate at
any of multiple bands; and a controller coupled to the plurality of antenna elements
to dynamically configure said each antenna element of the plurality of antenna elements
to operate at each of the multiple bands at different times.
[0061] Example 2 is the antenna of example 1 that may optionally include that the multiple
bands comprise two bands.
[0062] Example 3 is the antenna of example 2 that may optionally include that the two bands
are Ku and Ka bands.
[0063] Example 4 is the antenna of example 2 that may optionally include that the two bands
share the same receive (Rx) and transmit (Tx) radiating elements.
[0064] Example 5 is the antenna of example 1 that may optionally include that the plurality
of multi-band RF radiating antenna elements comprises a first sub-array of multi-band
RF radiating antenna elements for performing transmit (Tx) operations and a second
sub-array of multi-band RF radiating antenna elements for performing receive (Rx)
operations, and the first and second sub-arrays are interleaved across the aperture.
[0065] Example 6 is the antenna of example 1 that may optionally include that each RF radiating
antenna element comprises a slot loaded with one or more tunable components.
[0066] Example 7 is the antenna of example 6 that may optionally include that at least one
of the one or more tunable components comprises a varactor.
[0067] Example 8 is the antenna of example 6 that may optionally include that the slot is
loaded with at least one integrated circuit die.
[0068] Example 9 is the antenna of example 6 that may optionally include that the controller
is operable to independently control first and second resonances of the slot of each
of the plurality of multi-band RF radiating antenna elements to obtain operation of
the plurality of multi-band RF radiating antenna elements at each of the multiple
bands.
[0069] Example 10 is the antenna of example 9 that may optionally include first and second
dies containing first and second tunable components, respectively, of the one or more
tunable components and coupled across a width of the slot at a central portion of
the slot and at a location proximate to the edge of the slot without creating a short
circuit, respectively, such that influence on frequency band operation associated
with the first tunable component does not detrimentally affect frequency band operation
associated with the second tunable component, and vice versa.
[0070] Example 11 is the antenna of example 9 that may optionally include that the first
and second dies having two signal paths, with each signal path being associated with
one of the multiple bands and wherein the controller selects use of one of the two
signal paths according to which band of the multiple bands for which the slot is to
be operating.
[0071] Example 12 is the antenna of example 11 that may optionally include that each of
the two signal paths includes a switch, and wherein the controller is operable to
close the switch of each of the two signal paths to configure the slot for operation
with a band of the multiple bands that is associated with said each signal path.
[0072] Example 13 is the antenna of example 11 that may optionally include that the multiple
bands include a first band and a second band, and further wherein first and second
signal paths of the two signal paths includes a first filter having a passband for
the first band and a second filter having a passband for the second band.
[0073] Example 14 is the antenna of example 9 that may optionally include first and second
dies coupled across a width of the slot at a central portion of the slot and the second
die being coupled across the width of the slot at a location offset from the first
tunable component, respectively, wherein the first and second dies contain first and
second tunable components, respectively, with two signal paths respectively, the first
and second dies configured to independently control first and second frequency bands,
respectively, of the multiple bands.
[0074] Example 15 is the antenna of example 6 that may optionally include that at least
one of the one or more tunable components comprises a MEMS switch to change the electrical
length of the slot.
[0075] Example 15 is an antenna comprising: an aperture having a plurality of dual-band
radio-frequency (RF) radiating antenna elements, wherein each antenna element of the
plurality of dual-band RF radiating antenna elements is configurable to operate at
each of two bands, wherein the two bands share the same receive (Rx) and transmit
(Tx) radiating elements and each RF radiating antenna element comprises a slot loaded
with one or more tunable components; and a controller coupled to the plurality of
antenna elements to dynamically configure said each antenna element of the plurality
of antenna elements to operate at each of the dual bands at different times, wherein
the controller is operable to independently control first and second resonances of
the slot of each of the plurality of multi-band RF radiating antenna elements to obtain
operation of the plurality of multi-band RF radiating antenna elements at each of
the multiple bands.
[0076] Example 17 is the antenna of example 16 that may optionally include first and second
dies containing first and second tunable components, respectively, of the one or more
tunable components and coupled across a width of the slot at a central portion of
the slot and at a location close to the edge of the slot without creating a short
circuit, respectively, such that influence on frequency band operation associated
with the first tunable component does not detrimentally affect frequency band operation
associated with the second tunable component, and vice versa.
[0077] Example 18 is the antenna of example 17 that may optionally include that the first
and second dies have two signal paths, with each signal path being associated with
one of the multiple bands and wherein the controller selects use of one of the two
signal paths according to which band of the multiple bands for which the slot is to
be operating, and further wherein each of the two signal paths includes a switch,
and wherein the controller is operable to close the switch of each of the two signal
paths to configure the slot for operation with a band of the multiple bands that is
associated with said each signal path.
[0078] Example 19 is the antenna of example 16 that may optionally include that the two
bands are Ku and Ka bands.
[0079] Example 20 is a method comprising: configuring each antenna element of a plurality
multi-band radio-frequency (RF) radiating antenna elements to operate at a first band
at a first time; and configuring said each antenna element of a plurality multi-band
radio-frequency (RF) radiating antenna elements to operate at a second band at a second
time, wherein the first and second bands are different.
[0080] Example 21 is the method of example 19 that may optionally include independently
controlling first and second resonances of a slot of each of the plurality of multi-band
RF radiating antenna elements to obtain operation of the plurality of multi-band RF
radiating antenna elements at each of the first and second bands.
[0081] All of the methods and tasks described herein, in some embodiments, may be performed
and fully automated by a computer system. The computer system may, in some cases,
include multiple distinct computers or computing devices (e.g., physical servers,
workstations, storage arrays, cloud computing resources, etc.) that communicate and
interoperate over a network to perform the described functions. Each such computing
device typically includes a processor (or multiple processors) that executes program
instructions or modules stored in a memory or other non- transitory computer-readable
storage medium or device (e.g., solid state storage devices, disk drives, etc.). The
various functions disclosed herein may be embodied in such program instructions, or
may be implemented in application-specific circuitry (e.g., ASICs or FPGAs) of the
computer system. Where the computer system includes multiple computing devices, these
devices may, but need not, be co-located. The results of the disclosed methods and
tasks may be persistently stored by transforming physical storage devices, such as
solid-state memory chips or magnetic disks, into a different state. In some embodiments,
the computer system may be a cloud- based computing system whose processing resources
are shared by multiple distinct business entities or other users.
[0082] Depending on the embodiment, certain acts, events, or functions of any of the processes
or algorithms described herein can be performed in a different sequence, can be added,
merged, or left out altogether (e.g., not all described operations or events are necessary
for the practice of the algorithm). Moreover, in certain embodiments, operations or
events can be performed concurrently, e.g., through multi-threaded processing, interrupt
processing, or multiple processors or processor cores or on other parallel architectures,
rather than sequentially.
[0083] The various illustrative logical blocks, modules, routines, and algorithm steps described
in connection with the embodiments disclosed herein can be implemented as electronic
hardware (e.g., ASICs or FPGA devices), computer software that runs on computer hardware,
or combinations of both. Moreover, the various illustrative logical blocks and modules
described in connection with the embodiments disclosed herein can be implemented or
performed by a machine, such as a processor device, a digital signal processor (DSP),
an application specific integrated circuit (ASIC), a field programmable gate array
(FPGA) or other programmable logic device, discrete gate or transistor logic, discrete
hardware components, or any combination thereof designed to perform the functions
described herein. A processor device can be a microprocessor, but in the alternative,
the processor device can be a controller, microcontroller, or state machine, combinations
of the same, or the like. A processor device can include electrical circuitry configured
to process computer-executable instructions. In another embodiment, a processor device
includes an FPGA or other programmable device that performs logic operations without
processing computer-executable instructions. A processor device can also be implemented
as a combination of computing devices, e.g., a combination of a DSP and a microprocessor,
a plurality of microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration. Although described herein primarily with
respect to digital technology, a processor device may also include primarily analog
components. For example, some or all of the rendering techniques described herein
may be implemented in analog circuitry or mixed analog and digital circuitry. A computing
environment can include any type of computer system, including, but not limited to,
a computer system based on a microprocessor, a mainframe computer, a digital signal
processor, a portable computing device, a device controller, or a computational engine
within an appliance, to name a few.
[0084] The elements of a method, process, routine, or algorithm described in connection
with the embodiments disclosed herein can be embodied directly in hardware, in a software
module executed by a processor device, or in a combination of the two. A software
module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory,
registers, hard disk, a removable disk, a CD-ROM, or any other form of a non-transitory
computer-readable storage medium. An exemplary storage medium can be coupled to the
processor device such that the processor device can read information from, and write
information to, the storage medium. In the alternative, the storage medium can be
integral to the processor device. The processor device and the storage medium can
reside in an ASIC. The ASIC can reside in a user terminal. In the alternative, the
processor device and the storage medium can reside as discrete components in a user
terminal.
[0085] Conditional language used herein, such as, among others, "can," "could," "might,"
"may," "e.g.," and the like, unless specifically stated otherwise, or otherwise understood
within the context as used, is generally intended to convey that certain embodiments
include, while other embodiments do not include, certain features, elements or steps.
Thus, such conditional language is not generally intended to imply that features,
elements or steps are in any way required for one or more embodiments or that one
or more embodiments necessarily include logic for deciding, with or without other
input or prompting, whether these features, elements or steps are included or are
to be performed in any particular embodiment. The terms "comprising," "including,"
"having," and the like are synonymous and are used inclusively, in an open-ended fashion,
and do not exclude additional elements, features, acts, operations, and so forth.
Also, the term "or" is used in its inclusive sense (and not in its exclusive sense)
so that when used, for example, to connect a list of elements, the term "or" means
one, some, or all of the elements in the list.
[0086] Disjunctive language such as the phrase "at least one of X, Y, or Z," unless specifically
stated otherwise, is otherwise understood with the context as used in general to present
that an item, term, etc., may be either X, Y, or Z, or any combination thereof (e.g.,
X, Y, or Z). Thus, such disjunctive language is not generally intended to, and should
not, imply that certain embodiments require at least one of X, at least one of Y,
and at least one of Z to each be present.
[0087] While the above detailed description has shown, described, and pointed out novel
features as applied to various embodiments, it can be understood that various omissions,
substitutions, and changes in the form and details of the devices or algorithms illustrated
can be made without departing from the spirit of the disclosure. As can be recognized,
certain embodiments described herein can be embodied within a form that does not provide
all of the features and benefits set forth herein, as some features can be used or
practiced separately from others. The scope of certain embodiments disclosed herein
is indicated by the appended claims rather than by the foregoing description. All
changes which come within the meaning and range of equivalency of the claims are to
be embraced within their scope.
1. An antenna comprising:
an aperture having a plurality of multi-band radio-frequency (RF) radiating antenna
elements, wherein each antenna element of the plurality of multi-band RF radiating
antenna elements is configurable to operate at any of multiple bands; and
a controller coupled to the plurality of antenna elements to dynamically configure
said each antenna element of the plurality of antenna elements to operate at each
of the multiple bands at different times.
2. The antenna of claim 1 wherein the multiple bands comprise two bands.
3. The antenna of claim 2 wherein the two bands are Ku and Ka bands.
4. The antenna of claim 2 wherein the two bands share the same receive (Rx) and transmit
(Tx) radiating elements.
5. The antenna of claim 1 wherein the plurality of multi-band RF radiating antenna elements
comprises a first sub-array of multi-band RF radiating antenna elements for performing
transmit (Tx) operations and a second sub-array of multi-band RF radiating antenna
elements for performing receive (Rx) operations, and the first and second sub-arrays
are interleaved across the aperture.
6. The antenna of claim 1 wherein each RF radiating antenna element comprises a slot
loaded with one or more tunable components.
7. The antenna of claim 6 wherein at least one of the one or more tunable components
comprises a varactor
8. The antenna of claim 6 wherein the slot is loaded with at least one integrated circuit
die.
9. The antenna of claim 6 wherein the controller is operable to independently control
first and second resonances of the slot of each of the plurality of multi-band RF
radiating antenna elements to obtain operation of the plurality of multi-band RF radiating
antenna elements at each of the multiple bands.
10. The antenna of claim 9 further comprising first and second dies containing first and
second tunable components, respectively, of the one or more tunable components and
coupled across a width of the slot at a central portion of the slot and at a location
proximate to the edge of the slot without creating a short circuit, respectively,
such that influence on frequency band operation associated with the first tunable
component does not detrimentally affect frequency band operation associated with the
second tunable component, and vice versa.
11. The antenna of claim 9 wherein the first and second dies having two signal paths,
with each signal path being associated with one of the multiple bands and wherein
the controller selects use of one of the two signal paths according to which band
of the multiple bands for which the slot is to be operating.
12. The antenna of claim 11 wherein each of the two signal paths includes a switch, and
wherein the controller is operable to close the switch of each of the two signal paths
to configure the slot for operation with a band of the multiple bands that is associated
with said each signal path.
13. The antenna of claim 11 wherein the multiple bands include a first band and a second
band, and further wherein first and second signal paths of the two signal paths includes
a first filter having a passband for the first band and a second filter having a passband
for the second band.
14. The antenna aperture of claim 9 further comprising first and second dies coupled across
a width of the slot at a central portion of the slot and the second die being coupled
across the width of the slot at a location offset from the first tunable component,
respectively,
wherein the first and second dies contain first and second tunable components, respectively,
with two signal paths respectively, the first and second dies configured to independently
control first and second frequency bands, respectively, of the multiple bands.
15. The antenna of claim 6 wherein at least one of the one or more tunable components
comprises a MEMS switch to change the electrical length of the slot.
16. An antenna comprising:
an aperture having a plurality of dual-band radio-frequency (RF) radiating antenna
elements, wherein each antenna element of the plurality of dual-band RF radiating
antenna elements is configurable to operate at each of two bands, wherein the two
bands share the same receive (Rx) and transmit (Tx) radiating elements and each RF
radiating antenna element comprises a slot loaded with one or more tunable components;
and
a controller coupled to the plurality of antenna elements to dynamically configure
said each antenna element of the plurality of antenna elements to operate at each
of the dual bands at different times, wherein the controller is operable to independently
control first and second resonances of the slot of each of the plurality of multi-band
RF radiating antenna elements to obtain operation of the plurality of multi-band RF
radiating antenna elements at each of the multiple bands.
17. The antenna of claim 16 further comprising first and second dies containing first
and second tunable components, respectively, of the one or more tunable components
and coupled across a width of the slot at a central portion of the slot and at a location
close to the edge of the slot without creating a short circuit, respectively, such
that influence on frequency band operation associated with the first tunable component
does not detrimentally affect frequency band operation associated with the second
tunable component, and vice versa.
18. The antenna of claim 17 wherein the first and second dies have two signal paths, with
each signal path being associated with one of the multiple bands and wherein the controller
selects use of one of the two signal paths according to which band of the multiple
bands for which the slot is to be operating, and further wherein each of the two signal
paths includes a switch, and wherein the controller is operable to close the switch
of each of the two signal paths to configure the slot for operation with a band of
the multiple bands that is associated with said each signal path.
19. The antenna of claim 16 wherein the two bands are Ku and Ka bands.
20. A method comprising:
configuring each antenna element of a plurality multi-band radio-frequency (RF) radiating
antenna elements to operate at a first band at a first time; and
configuring said each antenna element of a plurality multi-band radio-frequency (RF)
radiating antenna elements to operate at a second band at a second time, wherein the
first and second bands are different.
21. The antenna of claim 20 further comprising independently controlling first and second
resonances of a slot of each of the plurality of multi-band RF radiating antenna elements
to obtain operation of the plurality of multi-band RF radiating antenna elements at
each of the first and second bands.