A novel technique to measure the input impedance of on-chip microstrip patch antenna in standard CMOS technology

This paper describes a novel technique to measure the input impedance of on-chip microstrip patch antenna in standard CMOS technology. By using the measured impedance of IMPATT diodes fabricated in the same standard CMOS technology and three lateral IMPATT diodes integrated with a microstrip patch antenna at one of the radiating edges, oscillation can be achieved and accurate measurement of the antenna input impedance can be extracted. The antenna used is 1.4 mm² and it is designed at 77 GHz by using the high frequency electromagnetic field solver Sonnet. The detected oscillation observed in the range of 75~77 GHz, with transmitted power of -62 dBm at 77 GHz. The measured input impedance is within 10% of the simulated one. It is hoped that this technique will provide accurate method to measure the input impedance in the millimeter-wave range of on-chip antenna with minimum near-filed perturbation.