A 60-GHz Power-Efficient Four-Element CMOS Phased-Array Transmitter With 31-dBm Peak EIRP for Short-Range Gb/s Wireless Transmission

Abstract

This study presents a 60-GHz four-element CMOS phased-array transmitter (Tx) along with a unit Tx element comprising a frequency-selective vector-sum phase shifter (VSPS), variable gain amplifier (VGA), and power amplifier (PA) in a 65-nm process. The unit Tx element with the proposed adaptive bias linearizer (ABL) delivers a measured peak gain of 25.6 dB, P-SAT of 11.1-15.1 dBm, and P-1dB of 10-13.2 dBm within a 3-dB bandwidth of 56-70 GHz. The rms gain and phase error during phase shift with 11.25 degrees resolution are <0.37 dB and <3.2 degrees in the 3-dB bandwidth, respectively. Using a four-unit Tx element, the phased-array Tx is synthesized with the I/Q up-converter, providing an unwanted leakage suppression of >50 dB. For the over-the-air (OTA) test, the Tx module is assembled using the four-element phased array and a half-wave dipole antenna with a director. The Tx module provides a peak electronic gain of 45.5 dB, while delivering a P-SAT of 29.2-30.8 dBm and P-1dB of 27.1-28.5 dBm within a 3-dB bandwidth of 56-68 GHz. The wireless transmission of 8-Gb/s 16-quadratic-amplitude modulation (QAM) and 4-Gb/s QPSK modulated signals was demonstrated at 1-and 4-m distances, respectively, while satisfying error vector magnitude (EVM) of -16.8 and -18.8 dB, respectively.