High-efficiency millimeter-wave CMOS phased-array transmitter for Gbps short-range wireless communication

Abstract

As the demand for high-speed communication increases, the mm-wave band is being considered increasingly considered. In particular, the unlicensed 60-GHz band (57 to 71 GHz) based on IEEE 802.11ay, is expected to be used in fields where a broadband spectrum is required for wireless AR/VR, wireless backhauls, and high-resolution radars. Recently, the fine beam-scanning technologies using large-scale phased arrays have been developed to widen the coverage and capacity in the mm-wave. However, they also require stringent circuit-level specifications due to the combination of multiple TX/RX channel combinations. The errors between elements result in increased sidelobes and equivalent isotropic radiated power (EIRP) loss in the scanned beam, causing the multipath fading and lowering the received signal-to-noise ratio (SNR). In addition, the large power consumption of several TX elements directly affects the reducing the operating time for mobile applications, so that the TX must provide the sufficient output power while ensuring the high efficiency.In this dissertation, a high-efficiency millimeter-wave CMOS phased-array transmitter for short-range wireless communication is proposed. For latency-free immersive wireless AR/VR, we aim to support the uncompressed >4K video transmission corresponding to data rate of >12 Gbps utilizing the several wide channels within 57 to 71 GHz. Considering the low-power/-cost systems for simplex wireless communication at 3-m distance, a 4-element phased-array transmitter supporting 16-QAM operation was implemented in CMOS 65-nm process. To improve both the linearity and the back-off power efficiency of the TX, an on-chip analog predistortion linearizer and an adaptive biasing network were proposed and integrated into the PA. And a frequency-selective vector-sum phase shifter (FS-VSPS) and a complementary-Gm compensated (CGC) variable gain amplifier that can have low RMS error in the wideband while finely controlling gain and phase, were proposed. In addition, a heterodyne I/Q up-converter with suppressed LO feedthrough and image leakages, was proposed to improve yield and minimize signal distortions of the TX. Based on proposed building blocks, a beamforming transmitter with an antenna-in-package capable of the beam steering was implemented, and the over-the-air (OTA) test was performed to evaluate the beam-steering and beam-tapering. Finally, the QPSK/16-QAM error vector magnitude (EVM) performance was finally verified in OTA test.This dissertation is organized of 5 chapters as follows. Chapter 1 is introduction. In chapter 2, the detail design of CMOS power amplifier with analog predistortion is discussed, and the implementation of PA with measurements are presented. In chapter 3, the high-efficiency 4-element phased-array transmitter IC is presented and measurements of the implemented TX are also provided. In chapter 4, array antenna design and over-the-air measurements of the beamforming transmitter with antenna-in-package is presented. Finally, the conclusion of this study is presented in Chapter 5.