Solid State Amplifier for Spread Spectrum Communications.

Abstract : The report describes development of a CW TRAPATT amplifier designed for use in spread spectrum communication systems. A diamond heat sink, required for high current density CW TRAPATT operation, was developed. The complementary n(+)pp(+) TRAPATT diodes developed exhibited superior performance over over their p(+) nn(+) counterpart. A pulsed peak power of 27 W with 42.5 percent conversion efficiency at 7.2 GHz and a CW power of 3 W with 24 percent conversion efficiency at 10.5 GHz were achieved as oscillators. A broadband TRAPATT amplifier was developed which yielded CW power of 4.7 W with 5 dB gain at 8.73 GHz and a DC to RF conversion efficiency of 18.5 percent. The amplifier had a 3 dB instantaneous bandwidth of 4.6 percent. AM and FM noise measurements were performed on this CW amplifier; the AM noise measured in a 1 KHz window was 110 dB below carrier and the FM noise was 100 dB below carrier. Phase linearity was also measured; the rms phase deviation was 4.36 degrees in a 3 dB bandwidth.