A reconfigurable, LTCC-based, ultra-wideband periodic leaky-wave antenna with circular polarization at 60 GHz

Abstract

Over the last decade, demand for higher data rates in the short-range wireless communication applications has rapidly grown. Bit-rates in the order of multi-Gb/s are very appealing these days; especially, utilizing the 7 GHz unlicensed bandwidth around the 60 GHz spectrum which is also known as the Wireless Gigabit Alliance (WiGig). Bringing multi-gigabit performance, near-zero latency and low interference to short-range indoor and outdoor applications, is not possible with traditional Wi-Fi anymore. The potential markets for the WiGig applications are VR/AR (Virtual Reality and Augmented Reality), smartphone-to-HDTV streaming, mobile cloud sync, super-fast public hot spots and 5G fixed wireless broadband. Antenna in Package (AiP) as a low-cost, low-profile and high performance antenna platform, has been proved to be a suitable solution for the mm-Wave communications. However, due to high attenuation level at this frequency range, an efficient, ultra-wideband antenna system with high radiation gain that supports circular polarization seems inevitable to overcome the limited connection range. Moreover, a narrow beam antenna must be equipped with 2-D beam steering capability to cover the maximum area of the room. Unfortunately, the existing antenna systems that are developed for 60 GHz band will not offer all these features at once in a single package. Other solutions have been developed, however, such designs include active devices such as motorized platform and active phase shifters that make the total system bulky and expensive. In this research project, we introduce an efficient periodic leaky-wave antenna (PLWA) with a high directive, reconfigurable radiation pattern in two directions. This antenna has a very simple and small-footprint structure, designed for the LTCC technology, which makes it easy to fabricate for the mm-Wave AiP applications and allows the budget-efficient repeatability of the mass production for a commercially suitable product. Moreover, it supports the circular polarization. Here, we will present an empirical model for the proposed antenna, the design and optimization process, the fabrication’s challenges on the LTCC substrate and the considerations for the measurements. We propose a phased-array of PLWAs structure fed by a Rotman lens with the beam scanning angle of −43° to +34° on the Y-Z plane and −31° to +28° on the X-Z plane for the frequency range of 50 GHz to 70 GHz. The complete structure fabricated on the Dupont 9K7 LTCC substrate includes only passive microstrip components and has a footprint of 15mm×38mm. The matching bandwidth of a single optimized PLWA is 29 GHz from 43 GHz to 72 GHz (fractional impedance bandwidth of 48.3%) and its average efficiency and peak realized gain over this frequency range are 87.42% and 11.25 dBi respectively. Also, the values of Axial Ratio and SLL are kept under 3 dB and -10 dB respectively.

Date	13 Aug 2021
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Dominic Deslandes (Supervisor)