A V-band 4096-QAM Modulator with AM-AM IQ Optimization for IRR Improvement Using 28nm CMOS Process

This paper proposed a V-band 4096-QAM OFDM modulator with AM-AM IQ Optimization for image rejection ratio (IRR) improvement and zero dc-power consumption fabricated in 28nm CMOS technology. With the technique of IRR optimization, the IRR can be improved over 20 dB than the previous measurement. At RF/LO port, compact passive transformer/balun were implemented to mitigate the metal loss and achieve better conversion gain performance. Also, the LO hybrid utilizes a converted-metal type 90-degree coupler for lowering I/Q imbalance. This modulator possessed a 3-dB conversion gain of -11 dB among 54-67 GHz. The measured IRR can reach greater than 40 dBc from 57-61 GHz and the peak IRR is 57 dBc at 58 GHz.