An injection locked sub-harmonic self-oscillating mixer for multi-band operation

A high-performance X-band subharmonic self-oscillating mixer (SOM) is proposed. By using a reconfigurable transistor pair in conjunction with open- and short-circuit stubs, the proposed SOM is capable of down-converting four RF frequency bands with center frequencies at 7.35, 8.65, 11.35, and 12.65 GHz with a conversion gain ranging from 7.83 to 18.7 dB. The measured phase noise of the free-running oscillation is -85.4 dBc/Hz at an offset frequency of 100 kHz. With injection locking, the phase noise is reduced to less than -100 dBc/ Hz at 10 kHz, without affecting the conversion gains. This is the first demonstration of a multiband subharmonic SOM. © 2004 Wiley Periodicals, Inc.