Merged power amplifier and mixer circuit topology for radar applications in CMOS

This paper presents a circuit topology merging power amplifier and mixer functionalities in a single circuit. The amplified local oscillator signal in the transmitter path is used simultaneously for the mixing operation along with the received radio-frequency signal, applied to the output of the power amplifier. The transistors at the output stage of the power amplifier are used for both amplification and passive mixing. The conversion loss of the mixer can be minimized, whilst the performance of the power amplifier is not affected. This approach is verified in measurement of a merged power-amplifier-mixer circuit in 0.13 mum CMOS technology. The mixer path offers a conversion loss of 10 dB, whilst the power amplifier achieves on-board output power of 7 dBm. The presented concept can be particularly advantageous for compact integrated monostatic radar solutions for low-cost mass-market applications.