A study of the impact of microwave radiation on an A/D converter

A 10-bit A/D converter with a maximum sampling rate of 60-mega-samples/sec (MSPS) (AD9051) has been radiated with microwaves at frequencies ranging from 15 to 20 GHz using a horn antenna with 20 dBi gain. The power level delivered to the antenna is varied from 10 to 19.4 dBm. ENOB/spl delta/ (modified effective number of bits) is defined and used to characterize the impact of microwave radiation on the operation of A/D converters. For the A/D converter used in this study, despite its least significant bit of 1.23 mV, the radiation had no discernable impact This result suggests that A/D converters may not be extremely sensitive to microwave radiations as originally thought.