Lossless Broadband Microwave Switches.
Interim technical rept. 1 Sep 78-31 Aug 79,
RAYTHEON CO WALTHAM MASS RESEARCH DIV
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The GaAs dual-gate MESFET is a very powerful microwave device offering more gain and a wider range of functional capabilities than a conventional single-gate FET. It has also been demonstrated that the dual-gate FET can be swithced from full off to full on in less than 50 psec. Combining the high gain and fast switching speed of this device with its inherently high isolation makes it an attractive candidate for microwave switching applications. This report describes the progress made during the first year of an effort to demonstrate the feasibility of using dual-gate FETs as high speed, broadband, lossless microwave switches. In this period, we have designed and fabricated two different dual-gate FET structures which functionally operate as multipole, multithrow switches with gain. We have achieved gains of 18 dB at 10 GHz from a more conventional dual-gate structure. This result is comparable to the best reported in the literature. We have also measured on-off ratios in excess of 30 dB and channel-to-channel isolation in excess of 25 dB in a multiport structure. Due to the many difficulties in handling multiport structures such as these, we have not yet been able to demonstrate signal switching. However, near the end of this report period we developed a new measurement technique which has the potential of eliminating many of the existing difficulties. Author
- Electrical and Electronic Equipment