A 24 GHz Receiver Front-end with Improved I/Q Balanced LO Generator in 65-nm CMOS for Surveillance Radar Systems

Abstract

A 24-GHz RF sensing receiver front-end with improved I/Q balanced LO generator is presented for a surveillance radar system. The proposed RF receiver front-end consists of a low-noise amplifier, an I/Q down-conversion mixer, and an I/Q local oscillator (LO) generator circuit. The proposed design method of a polyphase filter at millimeter-wave frequencies provides improved and balanced I/Q signals in comparison to a conventional polyphase filter. The receiver front-end draws 20-mA current from a 1.2-V supply voltage. The measured return loss of the RF input port is less than -10 dB in the range of 23.9–24.3 GHz. The receiver front-end achieves a conversion gain of 26.8 dB, noise figure (NF) of 5.1 dB, and an input 1-dB compression point (input P1dB) of -19.7 dBm in the 23.9–24.3 GHz range. Gain and phase mismatch between the I- and Q-paths at IF output are less than 0.15 dB and 0.3°, respectively.