0.13-µm CMOS load modulator for MIMO system

This paper presents load modulator based on the six-port modulator. To allow arbitrary load impedances to be used, a new circuit architecture with a technique to design the high resolution impedance is proposed and implemented. A theoretical model of the proposed modulator is derived. A 0.13-µm CMOS modulator utilizing MOSFET for impedance generation is designed and fabricated for a center frequency of 1.84 GHz for MIMO system. Measurements show good modulation properties when a 64 quadrature amplitude modulation signal is generated.