THERMOELECTRIC-POWER SENSOR FOR MICROWAVE APPLICATIONS BY COMMERCIAL CMOS FABRICATION

This letter describes an implementation of a thermoelectric microwave power sensor fabricated through commercial CMOS process with additiona l maskless etching, The sensor combines micromachined coplanar wavegui de and contact pads, a microwave termination which dissipates heat pro portionally to input microwave power, and many aluminum-polysilicon th ermocouples, The device was designed and fabricated in standard CMOS t echnology, including the appropriate superimposed dielectric openings for post-fabrication micromachining. By removing the bulk silicon loca ted beneath the device through micromachining, thermal and electromagn etic losses are minimized, The sensor measures signal true rms power i n the frequency range up to 20 GHz with input power in the -30 dBm to +10 dBm range, Over this 40 dB dynamic range, output voltage versus in put power is linear within less than +/-0.16%. Automatic network analy zer data show an acceptable input return loss of less than -30 dB over the entire frequency range.