Fully Integrated Dual-Mode X-Band Radar Transceiver Using Configurable Receiver and Local Oscillator

Keum-Won Ha,Goo-Han Ko,Jeong-Yun Lee,Jeong-Geun Kim,Young-Jin Kim,Donghyun Baek

doi:10.1109/access.2020.3016689

Abstract

In this paper, a fully-integrated dual-mode X-band radar transceiver that supports Doppler radar and frequency modulated continuous wave (FMCW) radar is proposed. To remove large off-chip DC-blocking capacitors in the Doppler mode, the double-conversion technique and local oscillator (LO) chopping technique are introduced. These techniques remove the DC offset and makes the transceiver more robust to the TX to RX leakage. In addition, they also improve the noise figure (NF) by filtering out 1/f noise of the analog baseband. The FMCW radar is realized using a direct-conversion receiver and a chirp generator. The chirp generator consists of a frequency sweep generator (FSG) and a fractional-N phase-locked loop (PLL). All the analog baseband components including a programable gain amplifiers (PGA) and 1/R 4 range compensation filters are integrated on the chip as well as a bandgap and low-dropout regulators. The operating frequency is from 9.7 to 12.3 GHz, which consumes 216 mW in Doppler mode and 201.6 mW in FMCW mode from a 1.2-V supply voltage. The maximum chirp bandwidth is 750 MHz and the maximum receiver gain is 76 dB with 6-dB gain step. The chip size of the transceiver is 7.68 mm 2 including all the pads.

Highlights

In recent years, the applications of radar sensors have been extended to various security systems, automated home appliances, autonomous driving assistance systems (ADAS), and unmanned aerial vehicles (UAVs) [1]–[9]
The proposed local oscillator (LO) is implemented by adding frequency sweep generator (FSG) blocks to the fractional-N phaselocked loop (PLL) using a method that controls the division ratio of the PLL
The proposed LO can reduce power consumption and chip size compared to using DDSbased structures, and it is easy to control dual-mode

Summary

INTRODUCTION

The applications of radar sensors have been extended to various security systems, automated home appliances, autonomous driving assistance systems (ADAS), and unmanned aerial vehicles (UAVs) [1]–[9]. The Doppler information exists in very low frequencies, from a few Hz to hundreds of Hz. Doppler radar has been widely adopted in low-cost motion sensors for detecting the presence of a moving object, because the decision circuit can be realized with a simple component such as a comparator or a low bitnumber analog-to-digital (ADC) converter. Since the baseband frequency of the FMCW radar is usually over several hundred kHz due to the chirping, it does not need large DC-decoupling capacitors, unlike Doppler radar. A fully integrated X-band radar transceiver that supports Doppler radar and FMCW radar simultaneously is proposed. The proposed radar integrated all the components needed for Doppler radar and FMCW radar on a single chip, except for the DC supply capacitors and the loop-filter capacitor for the PLL.

DUAL MODE RADAR

MEASUREMENT RESULTS

CONCLUSION