A Low-Cost and High-Gain 60-GHz Differential Phased Array Antenna in PCB Process

A broadband, low-cost, high-gain, multilayer differential antenna without air cavity is proposed for the 60-GHz phased array system. By using the standard low-cost printed circuit board process, a 60-GHz phased array antenna element and a 16-element phased array antenna prototype are implemented. To improve the bandwidth and antenna gain, a superstrate and a float rectangular ring are designed. The float ring can enhance the antenna vertical radiation, suppressing the antenna horizontal radiation and reducing the mutual coupling. Without any embedded air cavity, the proposed antenna is robust against the process variation, which is verified in the measurement. For the antenna element, the measured results demonstrate a peak gain of 8.9 dBi and a 10-dB return-loss bandwidth of more than 12 GHz, and the simulated radiation efficiency is above 90% at 60-GHz band. For the phased array antenna, two beam-fixed (0° and 30°) array antennas are tested to verify the beam scanning performance, which achieve gains of 16.3 and 13.6 dBi, respectively.

I. Introduction

Driven by the ever-increasing data-rate requirements, wireless communication enters the millimeter-wave (mm-wave) era. The unlicensed wideband spectrum around 60 GHz allows a wide range of emerging consumer products. In the past, to deal with the relatively high path loss at 60-GHz band (e.g., for 5-m link, the path loss is about 82 dB), a discrete high-gain antenna such as horn antenna is used to compensate the low output power of the power amplifier, with the penalty of high cost and large size [1]. Nowadays, with advanced CMOS process, several mm-wave transceivers with the integrated phased array antenna have been reported [2]–[7]. With this approach, beam scanning capability and high-gain performance can be achieved simultaneously, satisfying the link budget requirements of the 60-GHz line-of-sight and non-line-of-sight communication scenarios.