[0001] This invention relates to antennas for use with portable communication devices such
as mobile phones.
[0002] A robust design is necessary for portable communication devices because of the harsh
treatment inflicted on these devices during normal daily use. Some antennas are enclosed
within the housing of the device and are afforded protection from physical damage
by the housing. Many antennas, however protrude from and stand proud of the housing
and therefore are particularly susceptible to damage. Amongst prospective customers
for portable communication devices there is an expectation of low purchasing costs.
There exists also a highly competitive market for mobile phones and the like acting
as a spur to reduce manufacturing costs further.
[0003] The design and placement of an antenna for a radiotelephone is affected by a number
of factors including performance in radio transmission and reception, size, weight
and ease of manufacture and assembly into the communication device. Reductions in
costs for manufacturing are related,
inter alia, to the number of components in a particular sub-assembly and the time taken to incorporate
the sub assembly into the communication device.
[0004] Extendable antenna assemblies are prone to breakage and presently, so called stub
antennas are favoured. These stub antennas are less susceptible to breakage and generally
are more convenient for the user of the communication device. Owing to the expectation
of antenna breakages arising from previous designs some existing designs embody features
to allow easy replacement of the antenna. A snap-in feature has often been used to
provide for ease of replacement for antennas and other components or sub-assemblies.
[0005] Some prior art antennas with snap-in features are discussed in US 5 343 213 to Kottke,
US 5 949 386 to Elliott, US 5 809 135 to Chang and GB 2 308 013 assigned to Nokia
Mobile Phones Limited. Kottke provides resilient members depending co-axially from
the antenna section for temporary engagement with the housing via snaps included in
the resilient members. The extendable antenna is fitted in an axial direction. Elliott
also provides for a snap fit of an antenna by pushing the antenna into the housing
in an axial direction. A snap fit attachment in an axial direction is provided by
Chang to allow connection of a mobile phone to a car antenna. The snap fit antenna
mounting of GB 2 308 013 operates in an axial direction.
[0006] With regard to electronic devices it is axiomatic for manufacturers and suppliers
to discourage users from breaking the integrity of the main housing. Owing to the
damage sustained by prior art antennas, however, it is usual for the snap fit mechanisms
for antennas to provide for easy release from outside of the main housing. Provision
of an external release feature detracts from a firm attachment.
[0007] When antennas are inserted into the housing for attachment in an axial direction
it is necessary to provide additional components to secure the electrical path from
antenna to the internal circuits. The distance from the antenna contact to the internal
circuits via a PCB within the main housing may be small but additional components
with the attendant cost and assembly complications are required nevertheless. The
PCT pamphlet WO 99/50927 to Allgon AB discusses the problems associated with bridging
the gap between antenna and PCB and provides a means for interconnection.
[0008] It is an object of the invention to provide for a portable communication device an
antenna incorporating features for simple and firm attachment to a communication device
and requiring fewer components than heretofore.
[0009] According to the invention there is provided a snap-fit antenna for a portable communication
device, the antenna having attachment means and the device having a receptacle for
receiving the antenna and engaging the attachment means wherein the antenna engages
with and is secured within the receptacle in response to a lateral movement of the
antenna toward the receptacle.
[0010] An example of the invention will now be described with reference to the accompanying
drawings in which like reference numerals identify identical elements and in which:
figure 1 shows a rear view of a mobile phone housing with antenna in accordance with
the prior art,
figure 2 is a cross section through A-A of figure 1,
figure 3 is rear view of the antenna mounted in a phone,
figure 4 is a side elevation of figure 3,
figure 5 is an isometric view of the antenna assembled into the phone,
figure 6 is a is a side view of the antenna before assembly,
figure 7 is a cross section through B-B of figure 3,
figure 8 is an isometric view of the antenna before assembly.
[0011] With reference to figures
1 and 2 representations of a prior art antenna and mounting are shown. A main housing
1 has an integrally formed mounting
2 for support of the antenna
3. The prior art antennas of this type are assembled by means of operating a snap fit
connection in an axial direction as shown in figures 1 and 2. That is to say that
the antenna is pushed into the housing of the phone from a position around the top
of the phone in a direction along the longitudinal axis of the antenna (from P to
P'). As shown in figure 2 the longitudinal axis of the main housing along Q-Q' is
offset by a small angular amount from the longitudinal axis of the antenna P-P'.
[0012] The electrical radiating and receiving elements of the antenna terminate in a contact
4 which is connected to the internal circuitry of the phone via a contact assembly
5. The contact assembly
5 comprises a contact block
6 and a spring contact
7. A resilient member
8 provides a snap fit with the body of the mounting
2.
[0013] Figures 3 through 8 illustrate an antenna constructed in accordance with the present
invention and part of a mobile phone into which the antenna is attached. The antenna
shown generally at
11 comprises an active antenna element
12 and a base section
13. The active element
12 may be of any suitable type. Some suitable antenna types are; a helical coil wrapped
around a former (see US 5 341 149 for background) and a printed conductive filament
(see GB 2 330 951 for background). Many other antenna types e.g. patches, may be used
with the invention. Patch antennas are discussed in US 5 627 550. The profile of the
body of the antenna can be shaped to accommodate the particular type of active element
used and its matching circuits, if necessary.
[0014] The antenna
11 is shown in figures 3, 4 , 5 and 7 attached to the phone housing
20. In the figures 6 and 8 the antenna is shown detached from the housing. The direction
shown by the arrow
X of figure 7 is the axial direction referred to in relation to the prior art references.
The lateral direction used for attachment of the antenna in this example is shown
as arrow
Y in figure 6 and the arrow
Z in figure 8. In this instance the longitudinal axes of the antenna, housing and receptacle
are parallel one with another. More generally the longitudinal axes of the antenna
and receptacle are substantially parallel with each other but not necessarily are
the antenna and receptacle axes parallel with the axis of the housing.
[0015] Antenna base section
13 has a depending flange
14 carrying four snap catches
15. The snap catches
15 are resilient members incorporating a barb for engagement with the slots
18 within receptacle
21. A connector block
16 also depends from antenna base
13 and the connector block
16 carries at its distal end an electrical connector
17 which is connected within the base
13 to the active antenna element
12.
[0016] When the antenna is to be attached to the phone, the body of the antenna
11 is positioned adjacent the receptacle
21 and the antenna
11 is moved in a lateral direction toward the receptacle
21 as illustrated in figures 6 (direction
Y) and 8 (direction
Z). When the antenna
11 is inserted fully into the receptacle
21 the locking mechanism operates to secure the antenna in its mounted position. Locking
is effected by means of the barbs of the snap catches
15 which spring into slots
18 to secure the antenna within receptacle
21. With reference to figure 7 which shows the antenna attached to the housing, the electrical
connector 17 contacts the internal wiring of the phone via the PCB
19.
[0017] The antenna body around the base section and the corresponding parts of the receptacle
are shaped to provide an aesthetically pleasing profile. Conveniently the antenna
body can be fabricated by welding together a two part moulding of a suitable plastic
material e.g. PC/ABS. The two parts of the moulding are symmetrical about B-B of figure
3. The attachment means are therefore integral with and produced as part of the body
of the antenna. An additional benefit in terms of mechanical strength is realised
from the profiling of the antenna base section and the receptacle. As shown in the
figures the area and disposition of the mating surfaces between the antenna body and
the receptacle provide firm support. The user could not easily gain access to the
interior of the device to release the antenna from engagement. Nor would the user
be encouraged to do so because with the increased strength of the antenna attachment
the likelihood of damage is significantly reduced.
[0018] In accordance with current manufacturing techniques, electronic components are placed
on a PCB in a direction normal to the face of the board. This direction is therefore
the preferred direction of assembly of components for existing production machinery
and tooling. The antenna of the present invention is assembled in the preferred direction
so as to make less demands on the design of the production machinery and tooling.
There is provided thereby a further significant advantage over the prior art antennas
in this respect.
[0019] An automated test of the phone to include RF performance can proceed much more easily
before the antenna is assembled than was previously the case. Production testing of
the phone is also simplified because of the relatively straight forward access to
an RF test point where contact
17 would mate with the PCB
19. With prior art arrangements such as shown in figure 2, access to an RF test point
is problematic.
[0020] An antenna may be used whose axial direction, when mounted, makes a small angle with
the axis of the housing as is shown for the prior art illustration of figure 2. The
shape of the receptacle will need to accommodate the small angle and its axis aligned
for reception of a laterally moving antenna.
[0021] When the active antenna element is a patch antenna or another type of antenna with
a low profile, shaping of the antenna body and corresponding receptacle will allow
an assembled antenna to lie flush with the external housing of the portable device.
The antenna would not be recognised as such, in this arrangement and would be less
prone to damage.
[0022] In the exemplification of the invention given above, the antenna is mounted on the
outside of the housing. When it is desirable to mount an antenna within the main housing
of a device, however, the invention may also be carried into effect. For internal
antenna mounting attachment means carried on the antenna body engage with a receptacle
formed on an inner surface of one of the exterior housings of the device.
1. A snap-fit antenna for a portable communication device, the antenna having attachment
means and the device having a receptacle for receiving the antenna and engaging the
attachment means wherein the antenna engages with and is secured within the receptacle
in response to a lateral movement of the antenna toward the receptacle
2. A snap-fit antenna as in claim 1 in which the attachment means is integral with and
formed as part of the body of the antenna.
3. A snap-fit antenna as in claims 1 and 2 in which the attachment means comprises resilient
members carrying barbs for engagement with slots in the receptacle.
4. A snap-fit antenna as in any preceding claim mounted within the housing of the device.
5. A snap-fit antenna as in any preceding claim in which the portable communication device
is a mobile phone.
6. A snap-fit antenna as in any preceding claim in which the antenna is a patch antenna.
7. A snap-fit antenna substantially as described herein and as illustrated by the accompanying
drawings.