79 GHz Active Array FMCW Radar System on Low-Cost FR-4 Substrates

Abstract

This work, for the first time to our best knowledge, presents a W-band multi-channel frequency-modulated continuous-wave (FMCW) radar system on low-cost FR-4 substrates. A center-fed patch array antenna on an FR-4 substrate can achieve a maximum gain of 10.8 dBi. It is enabled by aperture coupled feeding using an on-chip feeder implemented on a CMOS radar transmitter (Tx) and receiver (Rx). The proposed radar system consists of one Tx and four Rx channels placed in the back cavity of a microstrip array antenna like an active array antenna system. Additionally, Tx and Rx chipsets include a wideband frequency multiplier with high multiplication ratio of 63, making it easy to distribute reference FMCW waveform synthesized at a very low frequency about 1.25 GHz for 79 GHz output using direct digital synthesis (DDS). Extending the number of channels and implementing various waveforms can be easily accomplished with very good phase noise. The functionality of the proposed radar system on low-cost substrates is confirmed by distance and angle measurements.

A 94-GHz High Resolution Radar Using Time Interleaving Active Array in 65-nm CMOS

“…The ×63 frequency multiplier chain consists of a ×7 frequency multiplier and two frequency triplers. The operational principles of these structures have been previously reported in [7]. While the fundamental structure remains unchanged, each , the optimal values for the FET size were determined to be a total width of 24 um, with a bias of 0.18 mA/um.…”

“…This integration method facilitates low-loss and compact integration of the RX and TX chips on the backside of antennas, thereby mitigating unwanted antenna pattern degradation caused by curved longdistance feedlines. A detailed explanation and the design process targeting 79 GHz have already been published in previous research [7]. The antenna integrated with the transceiver chip is 3 patch array antenna and designed on a Rogers RT/Duroid 5880 with a thickness of 127 um, dielectric constant of 2.2, loss tangent of 0.0013.…”

System Performance of a Scalable 79 GHz Imaging MIMO Radar With Injection-Locked LO Feedthrough

“…For a signal distribution at the operating frequency [8], the high losses on a printed circuit board (PCB) limit the maximum transmission line length and therefore the size of the radar sensor. To overcome this limitation, the FMCW signal is often distributed at a lower frequency and is later multiplied or up-converted within the radar monolithic microwave integrated circuit (MMIC) [9]. This also enables operating frequencies above 100 GHz [10].…”

Antenna Element Space Interference Cancelling Radar for Angle Estimations of Multiple Targets

“…Recently, frequency-modulated continuous wave (FMCW) radar systems using the millimeterwave frequency band have been widely used in autonomous driving systems or advanced driver assistant systems (ADASs) [1]. Compared with camera sensors, millimeter-wave radars can be smaller in size, simpler in structure, lower in cost [2], and more robust to weather [3] and curved roads [4]. Four basic pieces of information: range, velocity, angle, and size, are necessary for radar target recognition/imaging.…”