A One-Watt CW High-Efficiency X-Band Avalanche-Diode Amplifier (Correspondence)

An X-band avalanche-diode amplifier circuit is described which provides accurate and independent in-band impedance control (R and +jx) and orthogonal second-harmonic reactance control. Low-level gains of 13 dB with 500 MHz of bandwidth have been achieved using this circuit. Power outputs of 1 watt CW with 5 dB of gain and 14.7-percent generation efficiency have also been realized by carefully controlling the in-band and second-harmonic load impedance.