28 GHz Gapwaveguide-based Phased Array Antennas for 5G Applications

Abstract

The fifth generation (5G) of mobile wireless communication aims to provide higher data capacity than the previous generations could. With large frequency bands already licensed at mmWaves, data rates of around 10 Gbit/s can be offered. However, these frequency bands lead to more free space path loss, for example, 20 dB more loss moving from 3 to 30 GHz. Phased array antennas integrated with low-loss antenna elements and high-power front-ends have drawn much attention to compensate for this increased loss.State-of-the-art phased array antennas for mmWave 5G are designed with antenna elements based on a dielectric substrate and employ front-ends with CMOS and SiGe BiCMOS technology. The antenna elements based on a dielectric substrate typically show a high loss at mmWave frequencies and suffer from low bandwidth. The techniques to increase the bandwidth of such antenna elements usually add to the complexity of the structure by increasing the number of layers. This thesis aims to use gapwaveguide technology as the baseline for antenna element design, which is a low-loss, low-cost, and wideband transmission line at mmWave frequencies.In this thesis, a phased array is designed with improved characteristics in terms of low antenna and front-end losses. The objective is to propose a costeffective and scalable phased array while enhancing its complex structure. For 5G communication systems operating at 28 GHz, a high equivalent isotropic radiated power (EIRP) active phased array antenna is proposed. The antenna design is based on the gapwaveguide technology and consists of 16 × 16 single 45 • slant-polarized elements. The proposed design employs a low-complexity printed circuit board (PCB) structure with only six layers, i.e., half of existing wideband solutions. The array antenna incorporates up/down converter integrated circuits (UDCs) and 1 × 4 transceiver beamformer integrated circuits (BFICs). Moreover, a compact and highly efficient transition at the end of each channel of the BFICs has been designed to interconnect the antenna elements with the PCB. The antenna's front-end loss, which includes the feed line, mismatch, and ohmic losses, is only 1.3 dB. The array covers a scanning range of ±60 • in the azimuth plane and ±10 • in the elevation plane. The S 11 < −10 dB frequency bandwidth is from 26.5 − 29.5 GHz. The maximum EIRP of the antenna is 65.5 dBm at the saturation point. The presented design offers a compact, robust, and low-loss performance solution meeting the high v vi Summary x SamenvattingAt the end of this journey, I'm deeply grateful to the many individuals who supported, guided and contributed to this thesis. Their efforts, from mentors to friends, have shaped the growth and outcome of this work.First, I would like to express my deepest appreciation to my main supervisor Senior Associate Professor Andrés Alayón Glazunov for the opportunity to this fruitful PhD journey. His immense support, constructive guidance, and unwavering encouragement have been very valuable throughout this project. Thanks for ...