For a typical FMCW automotive radar system, a new design of baseband signal processing architecture and algorithms is proposed to overcome the ghost targets and overlapping problems in the multi-target detection scenario. To satisfy the short measurement time constraint without increasing the RF front-end loading, a three-segment waveform with different slopes is utilized. By introducing a new pairing mechanism and a spatial filter design algorithm, the proposed detection architecture not only provides high accuracy and reliability, but also requires low pairing time and computational loading. This proposed baseband signal processing architecture and algorithms balance the performance and complexity, and are suitable to be implemented in a real automotive radar system. Field measurement results demonstrate that the proposed automotive radar signal processing system can perform well in a realistic application scenario.

/pdf/design-of-an-fmcw-radar-baseband-signal-processing-system-jzf331ehka.pdf

Design of an FMCW radar baseband signal processing system for automotive application

Reactive matching is extended to wide bandwidths using the impedance property of LC-ladder filters. In this paper, we present a systematic method to design wideband low-noise amplifiers. An SiGe amplifier with on-chip matching network spanning 3-10 GHz delivers 21-dB peak gain, 2.5-dB noise figure, and -1-dBm input IP3 at 5 GHz, with a 10-mA bias current.

A 3-10-Ghz low-noise amplifier with wideband LC-ladder matching network

A radar system with an ultra-wide FMCW ramp bandwidth of 25.6 GHz (≈32%) around a center frequency of 80 GHz is presented. The system is based on a monostatic fully integrated SiGe transceiver chip, which is stabilized using conventional fractional-N PLL chips at a reference frequency of 100 MHz. The achieved in-loop phase noise is ≈ -88 dBc/Hz (10 kHz offset frequency) for the center frequency and below ≈-80 dBc/Hz in the wide frequency band of 25.6 GHz for all offset frequencies >;1 kHz. The ultra-wide PLL-stabilization was achieved using a reverse frequency position mixer in the PLL (offset-PLL) resulting in a compensation of the variation of the oscillators tuning sensitivity with the variation of the N-divider in the PLL. The output power of the transceiver chip, as well as of the mm-wave module (containing a waveguide transition), is sufficiently flat versus the output frequency (variation <;3 dB). In radar measurements using the full bandwidth an ultra-high spatial resolution of 7.12 mm was achieved. The standard deviation between repeated measurements of the same target is 0.36 μm.

An Ultra-Wideband 80 GHz FMCW Radar System Using a SiGe Bipolar Transceiver Chip Stabilized by a Fractional-N PLL Synthesizer

This paper presents a portable radar system for short-range localization, inverse synthetic aperture radar imaging, and vital sign tracking. The proposed sensor incorporates frequency-modulated continuous-wave (FMCW) and interferometry (Doppler) modes, which enable this radar system to obtain both absolute range information and tiny vital signs (i.e., respiration and heartbeat) of human targets. These two different operation modes can be switched through an on-board microcontroller. To simplify the system, the proposed radar utilizes the audio card of a laptop to sample the baseband signal. The FMCW mode of the radar uses operational-amplifier-based circuits to generate an analog sawtooth signal and a reference pulse sequence (RPS). The RPS is locked to the sawtooth signal to obtain coherence for the radar system. For the interferometry mode, a low-intermediate-frequency modulation method is implemented to avoid the slow vital signs from being distorted by the high-pass filter of the audio card. Several experiments were carried out to reveal the capability and distinct operational features of the proposed portable hybrid radar. The experiments also showed that the system can easily detect glass, which is usually difficult to identify for optical-based sensors. In addition, 2-D scanning in a complex environment revealed that the proposed radar was able to differentiate human targets from other objects. Moreover, ISAR images were used to isolate moving human targets from surrounding clutter. Finally, the proposed radar also demonstrated its ability to accurately measure vital signs when a human subject sits still.

A Portable FMCW Interferometry Radar With Programmable Low-IF Architecture for Localization, ISAR Imaging, and Vital Sign Tracking

This paper will review the main sensor technologies used to create an autonomous vehicle. Sensors are key components for all types of autonomous vehicles because they can provide the data required to perceive the surrounding environment and therefore aid the decision-making process. This paper explains how each of these sensors work, their advantages and disadvantages and how sensor fusion techniques can be utilised to create a more optimum and efficient system for autonomous vehicles.

Sensor Technology in Autonomous Vehicles : A review

A fully-integrated FMCW radar system for automotive applications operating at 77 GHz has been proposed. Utilizing a fractional- synthesizer as the FMCW generator, the transmitter linearly modulates the carrier frequency across a range of 700 MHz. The receiver together with an external baseband processor detects the distance and relative speed by conducting an FFT-based algorithm. Millimeter-wave PA and LNA are incorporated on chip, providing sufficient gain, bandwidth, and sensitivity. Fabricated in 65-nm CMOS technology, this prototype provides a maximum detectable distance of 106 meters for a mid-size car while consuming 243 mW from a 1.2-V supply.

A Fully-Integrated 77-GHz FMCW Radar Transceiver in 65-nm CMOS Technology

Millimeter-wave anti-collision radars have been widely investigated in advanced CMOS technologies recently. This paper presents a fully integrated 77GHz FMCW radar system in 65nm CMOS. The FMCW radar transmits a continuous wave which is triangularly modulated in frequency and receives the wave reflected from objects. As can be illustrated in Fig. 11.2.1, for a moving target, the received frequency would be shifted (i.e. Doppler shift), resulting in two different offset frequencies f + and f− for the falling and rising ramps. Denoting the modulation range and period as B and T m , respectively, we can derive the distance R and the relative velocity V R as listed in Fig. 11.2.1, where f c represents the center frequency and c the speed of light.

A fully integrated 77GHz FMCW radar system in 65nm CMOS

This paper presents two fully integrated binary phase-shift keying (BPSK) and quadrature phase-shift keying (QPSK) transceivers operating at W-band [carrier frequency = 84 GHz (BPSK), and 87 GHz (QPSK)]. Including RF front-end, Costas-loop-based carrier and data recovery, and antenna assembly technique, the BPSK transceiver prototype achieves a 2.5-Gb/s data link with BER <; 10-9 while consuming 202 mW (Tx) and 125 mW (Rx) from a 1.2-V supply. The QPSK TRx achieves a 2.5-Gb/s data link with BER <; 10-11 while consuming 212 mW (Tx) and 166 mW (Rx) from a 1.2-V supply. Both cases are measured with link distance of 1 m and antenna gain of 24 dBi.

$W$ -Band BPSK and QPSK Transceivers With Costas-Loop Carrier Recovery in 65-nm CMOS Technology

This work presents a novel 77GHz automotive radar providing detection distance and angle up to 100m and ±8°, respectively. Using a 1TX/4RX array, this radar system employs various mmWave techniques to fulfill the expected SNR.

A Fully-Integrated 77GHz phase-array radar system with 1TX/4RX frontend and digital beamforming technique

Modern high-speed wireless data links such as 60GHz RF and point-to-point communications activate research on Gb/s transceivers for V-band (50 to 75GHz) and W-band (75 to 110GHz). Conventional approaches in SiGe or III-V compounds simply consume too much power and occupy too large area, in addition to the integration difficulty. In CMOS realizations, baseband processors and high-speed digitizers also increase design complexity and power consumption. This paper introduces a fully integrated CMOS QPSK transceiver with baseband-less carrier- and data-recovery circuitry, significantly reducing power consumption while achieving up to 3.5Gb/s data rate.

Shih-Jou Huang

Papers

A Fully-Integrated 77-GHz FMCW Radar Transceiver in 65-nm CMOS Technology

A fully integrated 77GHz FMCW radar system in 65nm CMOS

$W$ -Band BPSK and QPSK Transceivers With Costas-Loop Carrier Recovery in 65-nm CMOS Technology

A Fully-Integrated 77GHz phase-array radar system with 1TX/4RX frontend and digital beamforming technique

An 87GHz QPSK transceiver with costas-loop carrier recovery in 65nm CMOS