Local oscillator subsystem design for DAMA-SCPC system

A LO subsystem with low cost, small size and low close-in phase noise has been developed for DAMA-SCPC system. Using the contrived loop gain control circuit, the loop gain in the full tuning band of the Ku-band synthesizer was uniformly kept, and the measured phase noise variations over the whole tuning band were within a maximum of 1 dB. The SSB phase noise obtained from the 13.555 GHz synthesizer output was as low as -88 dBc/Hz at 30 kHz offset, and the integrated phase noise over 30 Hz to 30 kHz offset was 0.96 RMS degrees. The nominal output power of the Ku-band synthesizer was 13 dBm and its flatness was less than 1 dB/sub (p-p/) in the full tuning band.