| 摘要 |
A monolithic high frequency downconverter which utilizes a three-stage low-noise amplifier, a singly balanced mixer, and a two-stage intermediate frequency amplifier. The downconverter is suitable for applications in a range of systems utilizing EHF frequencies, such as satellites, or phased array antennas. Other applications include RF front end of smart weapons operating at frequencies ranging from 35 to 94 GHz, and avionic systems employing channelized receivers and EW (electronic warfare) systems. The three-stage low-noise amplifier employs four-gate finger HEMT devices for reduced gate resistance and source impedance matching. The singly balanced active HEMT mixer employs a compact 180- rat-race hybrid ring which significantly reduces the chip size and provides low conversion loss, high LO to RF isolation, high output, IP3 and high-spur rejection as compared to single-ended mixer designs. The circuit design techniques of the present invention are applicable at frequencies ranging from 10 to 100 GHz. AlGaAs/GaAs HEMT and AlGaAs/InGaAs HEMT versions have been produced. The downconverter of the present invention eliminates hybrid assembly and tuning, has a smaller size, lighter weight, and lower DC power consumption.
|
