A 77–81-GHz 16-Element Phased-Array Receiver With $\pm {\hbox{50}}^{\circ}$ Beam Scanning for Advanced Automotive Radars

A 16-element phased-array receiver has been developed for advanced W-band automotive radars. The phased-array receiver is based on a single SiGe chip with RF beamforming capabilities, which is packaged using low-cost bond-wire techniques and attached to a 16-element linear microstrip array. The antenna results in a directivity of 29.3 dB and a gain of 28.0 dB at 77–81 GHz, and can be scanned to $\pm {\hbox{50}}^{\circ}$ in the azimuth plane in $\sim {\hbox {1}}^{\circ}$ steps. The packaging details are presented together with the steps taken to ensure a wideband impedance match and low coupling between the phased-array channels. Gain measurements done at 79 GHz agree well with simulations. The 16-element phased array receiver was used with a 2-element frequency-modulated continuous-wave transmitter at 76.5–77 GHz and high-resolution millimeter-wave images were obtained. The work shows that complex millimeter-wave phased arrays can be packaged using traditional bond-wire techniques, and can be a powerful solution for advanced automotive radars.

I. Introduction

Silicon-Based W-band automotive radars are currently in wide use by the automotive industry for collision avoidance and cruise control, and several silicon chips have been developed with scanning or switch-beam capabilities [1]–[13]. The scanning systems are based on digital or RF beamforming techniques, and have shown great potential for automatic cruise control and collision avoidance systems. An example of such Fig. 1.

Millimeter-wave automotive radar system architecture: 16-element receiver and 2-element transmitter.

development is the 16-element phased-array receiver chip with built-in-self-test capabilities [14] and its related packaging [15]. This work expands on [15] and presents details of the low-cost packaging with a complete study of the bond-wire inductance effects and coupling between the channels (Fig. 1). It also presents details of the low-cost printed-circuit board, antenna design, and system-level measurements including gain, noise, and millimeter-wave imaging applications.