A Ka-Band Radar Receiver with Built-in X8 Multiplier

This paper proposes a 32 GHz band radar receiver with an X8 multiplier. The Ka-band Rx chip used in the receiver was fabricated by using a 28-nm complimentary metal-oxide-semiconductor (CMOS) process and its built-in X8 multiplier enables the chip to driven by a low reference signal of 4 GHz. The designed Rx chip was attached to the ground plane of a microstrip patch antenna and connected to the feedline via the bonding wire. The impedance matching circuit was implemented along the antenna feedline by considering the impedance changes caused by the bonding wire. The reference input signal, intermediate frequency (IF) output, and bias of the receiver were supplied on an FR4 substrate with a cavity, which enabled easy implementation of the Ka-band receiver module without requiring expensive and precise packaging technology. The performance of the fabricated receiver module was verified in an over-the-air (OTA) test.