Injection-locked oscillator as frequency multiplier for millimeter-wave applications

This paper describes the design of an injection-locked oscillator and demonstrates its use as a compact and efficient doubler or a tripler. The ILO has a free-running oscillating frequency of 28.5 GHz and output power of 7 dBm. With second subharmonic injection of 11 dBm, it produces >7 dBm from 26.5 GHz to 33.5 GHz with a maximum of 10 dBm at 30.5 GHz. With third subharmonic injection of 11 dBm, it produces >1 dBm from 28.5 GHz to 32 GHz with a maximum of 4 dBm at 30 GHz. The tripled output at 30 GHz has a spot noise of -102 dBc/Hz at 100 kHz offset. The MMIC was fabricated utilizing Nortel Networks´ GaAs/InGaP HBT with ft of 70 GHz and fmax of 110 GHz.