A Low-Power 24-GHz Radar Transceiver for Automotive Hands-Free Trunk Opener Applications in a 0.13μm SiGe BiCMOS Technology

This paper presents a 24-GHz radar system based on a low-power, low-noise, multichannel monolithic microwave integrated circuit (MMIC) for automotive hands-free trunk opener applications. The MMIC features two transmit (TX) and two receive (RX) channels. Each TX section features a fundamental frequency voltage controlled oscillator (VCO) with an 8-bit Digital-to-Analog converter (DAC) based tuning voltage source. A combination of a prescaler and frequency counter is used for on-chip monitoring of the transmission frequency. The TX delivers a maximum output power of +10 dBm. Two stages of variable gain amplifiers (VGA) configurable with a 5-bit DAC provide a dynamic range greater than 20 dB. Each RX section consists of a low noise amplifier (LNA) multiplexed to a single homodyne quadrature downconverter stage with a single-sideband noise figure (NFssb) lower than 8 dB and an adjustable conversion gain (CG) of upto 26 dB. The downconverted IF signals are further amplified by integrated programmable dc-coupled analog baseband (ABB) amplifiers with upto 50 dB of gain, and digitized by integrated 8-bit Analog-to-Digital (ADC) converters. The receivers integrate a dc-offset compensation circuit with upto +/- 200 mV. Designed in a 0.13 mu m SiGe:C BiCMOS technology with f(T)/f(max) of 250/380GHz, the chip consumes a maximum current of 150 mA from 1.8 V, and less than 75 mu A in the standby mode.