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.

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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

This paper presents a 60-GHz direct-conversion transceiver using 60-GHz quadrature oscillators. The transceiver has been fabricated in a standard 65-nm CMOS process. It in cludes a receiver with a 17.3-dB conversion gain and less than 8.0-dB noise figure, a transmitter with a 18.3-dB conversion gain, a 9.5-dBm output 1 dB compression point, a 10.9-dBm saturation output power and 8.8-% power added efficiency. The 60-GHz frequency synthesizer is implemented by a combination of a 20-GHz PLL and a 60-GHz quadrature injection-locked oscillator, which achieves a phase noise of -95 dBc/Hz@l MHz-offset at 60 GHz. The transceiver realizes IEEE802.15.3c full-rate wireless communication for all 16QAM/8PSK/QPSK/BPSK modes, and the communication distances with the full data rate using 2.16-GHz bandwidth, measured with an antenna built in the package, are 2.7-m (BPSK/QPSK) and 0.2-m (8PSK/16QAM). The measured maximum data rates are 8 Gb/s in QPSK mode and 11 Gb/s in 16QAM mode over a 5 cm wireless link within a bit error rate (BER) of <;10-3. The transceiver consumes 186 mW from a 1.2-V supply voltage while transmitting and 106 mW from 1.0-V supply voltage while receiving. Both transmitter and receiver are driven by a 20-GHz PLL, which consumes 66 mW, including output buffer, from a 1.2-V supply voltage.

A 60-GHz 16QAM/8PSK/QPSK/BPSK Direct-Conversion Transceiver for IEEE802.15.3c

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

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

A fully-integrated 60-GHz transceiver utilizing analog FSK modulation/demodulation to replace baseband processor has been demonstrated. Employing a discriminator with automatic adjustment and a folded dipole antenna pair (5-dBi gain for each), the transceiver achieves > 1Gb/s data transmission over 1 meter with BER < 10−12 while consuming a total power of 500 mW.

A 60-GHz FSK transceiver with automatically-calibrated demodulator in 90-nm CMOS

An all-digital polar transmit (TX) architecture exhibits advantages of low cost, low power, as well as reconfigurability with full usage of digital computational power. The design challenge is the need for continuous innovation to further enhance power efficiency and minimize silicon area while achieving the best-in-class RF performance. The design must also meet the increasing demand of concurrent operation for multi-radio SoC integration. The presented Bluetooth TX demonstrates advancements in this direction with over 30% power and 66% area reduction.

A 0.27mm 2 13.5dBm 2.4GHz all-digital polar transmitter using 34%-efficiency Class-D DPA in 40nm CMOS

This paper describes a dual-band 802.11abgn/ac compliant transceiver in a 4-in-l combo connectivity SoC. It integrates the PAs, LNAs, T/R switches, and the 5GHz Balun. Due to the transmitter architecture and adaptive biasing scheme both are tailored for wide bandwidth, the 5GHz transmitter achieves 18.2dBm average output power for 802.11ac VHT80 MCS9 (Modulation and Coding Scheme 9). Within the 80MHz channel bandwidth, the IQ mismatch becomes frequency dependent, and is compensated through calibration. In the 2.4GHz transmitter, its PA load-line is adjustable. The power efficiency is thus remained similarly regardless the output power is at 20dBm for long range operation, or 8dBm for short range operation. By controlling the turn-on resistance of power island switch in digital baseband, and properly sizing the filler cap, the switching noise can be well controlled. The chip occupies 24.9mm2 in 55nm 1P6M CMOS technology, where 1.3mm2 is for 5GHz WLAN and 2.1mm2 is for 2.4GHz WLAN/BT.

Meng-Hsiung Hung

Papers

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

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

A 60-GHz FSK transceiver with automatically-calibrated demodulator in 90-nm CMOS

A 0.27mm 2 13.5dBm 2.4GHz all-digital polar transmitter using 34%-efficiency Class-D DPA in 40nm CMOS

A dual-band 802.11abgn/ac transceiver with integrated PA and T/R switch in a digital noise controlled SoC