Study and Fabrication of a Frequency Divider-Multiplier Scheme for High-Efficiency Microwave Power

The design, fabrication, and experimental evaluation of an exploratory 8.2 W, microwave FM power amplifier for the 4-GHz band are presented. It operates on a frequency divide, amplify, and multiply scheme receiving about 2-4 dBm of FM signal in the 4-GHz band, divides the frequency coherently by two, amplifies the modulated signal to about 10.4 W, and doubles the frequency coherently, yielding about 8.2 W into standard 50-ω 4-GHz load, with an overall efficiency of about 30 percent. Frequency halving is accomplished by a wideband regenerative frequency divider yielding about 1-2 dBm of signal at 1995 MHz. The signal is amplified by commercial class C amplifiers and is restored to the 4-GHz band by a stacked varactor containing two 0.32 ω, 15-pF chips in a coaxial embodiment. This entire ensemble, with a total breakdown of 160 V, serves as a frequency doubler.