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(11) | EP 1 077 502 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | MMIC-to-waveguide RF transition and associated method |
| (57) An RF transition for coupling energy propagating in a waveguide transmission line
into energy propagating in a monolithic microwave integrated circuit ("MMIC") is provided.
The RF transition comprises a microstrip structure that includes a MMIC substrate
with backside metallization and a front side microstrip. The backside metallization
defines an iris, and the microstrip includes a microstrip feed formed proximate the
iris. The RF transition also includes a waveguide terminating at the metallization
layer around the iris to thereby convert energy propagating in the waveguide into
energy propagating in the microstrip. In one embodiment, RF signal processing circuitry
is monolithically formed on the MMIC substrate. The invention enables a waveguide-to-MMIC
transition to be constructed at higher RF frequencies, such as millimeter wave frequencies,
even with the fragile, thinner substrates and smaller device features of higher-frequency
devices. The monolithic structure avoids the use of wire bonds or ribbon welds to
interconnect separate substrates, such as would be used in an MIC implementation,
enabling improved RF performance at higher RF frequencies. The invention enables an
RF circuit to be constructed that is adapted to communicate signals with a waveguide
at higher RF frequencies, such as millimeter wave frequencies, in a rugged, producible
package. |