Projects:2021s1-13113 Miniaturised metasurface antennas

Abstract here

Introduction

In this modern age, there is an ever growing demand for wireless communication, resulting to an increasing use of antennas. In portable devices, integrated antennas are becoming more common, as their compact size and nature proves ideal to have a compact and elegant solution, removing the need for traditional, external antennas. There is also an evergrowing number of wireless connection protocols, requiring unique antennas to support each protocol. A typical phone will include at minimum, 3G, Wifi, Bluetooth and GPS antennas.
With many designs in technology, there is a reoccuring theme of attempting to shrink designs, whilst maintaining or improving upon performance. Antennas are not neglected from this, with a particular interest in integrated antennas. Antenna design has physical limitations, as the size of the antenna is dependent on the operating frequency. For lower frequency operations, this proves problematic, as there are greater wavelengths, resulting in larger antennas. This is where a technique known as 'metasurfacing' can be used to miniaturise lower frequency integrated antennas, whilst complying with the physical limitations. This technique involves the periodic arrangement of small elements above the dielectric material, which affects the reflection and transmission of electromagnetic waves. The use of this metasurfacing technique will be explored, and attempted to be utilised to miniaturise a patch antenna, whilst maintaining or improving antenna performance such as bandwidth, and directive gain.

Project team

Project students

• Galvin Chuong
• Isaac Do

Supervisors

• Dr Christophe Fumeaux
• Dr Shengjian Chen (Jammy)
• David de Haaij (Black Arts Technology)

Objectives

The objective of this project focuses on two final desigs of the miniaturised metasurface antenna with the operating frequency at 900 MHz. These designs must match or improve the performance of the antenna before miniaturisation. The antennas must satisfy the bandwidth of 900 MHz – 928 MHz. These final designs will include many milestones, mainly revolving around many design processes until the final design is reached. These include a benchmark antenna, recreation of past literature antennas, first design of a metasurface antenna and then the final design before fabrication. The designs are created and simulated using CST Studio Suite, a 3D Electromagnetic simulation and analysis software.

Background

Topic 1

Since patch antennas are being modified to implement metasurfaces to reduce the antenna size, background about patch antennas and their properties are required. Patch antennas are inexpensive, robust low-profile antennas which have been used in this modern age for many applications, ranging from spacecraft applications to mobile and wireless communication. However, their main drawbacks are their lack of efficiency and power, its narrow bandwidth and their physical size when operating at low frequencies.

The patch antenna is composed with a patch, dielectric substrate, ground plane and a feed line. The patch of the antenna is a very thin metallic patch which is placed on top of a ground plane but separated by a dielectric substrate that is a small fraction of a wavelength in height

Figure 1: Edited excerpt from Antenna Theory: Analysis and Design, Labelled diagram of a typical microstrip antenna design

The patch antenna properties can be altered when replacing the singular patch with a periodic arrangement of metallic patches. This is also known as a metasurface patch, which will alter the space waves emitted from the metasurface patches. The radiated space waves will yield different reflection and transmission properties compared to the singular patch. The gaps between the patches also act as radiating and non-radiating slots, which can excite multiple modes. These multiple excited modes can increase the bandwidth if designed correctly, allowing a higher bandwidth which will help in maintaining performance when miniaturising.

References

[1] a, b, c, "Simple page", In Proceedings of the Conference of Simpleness, 2010.

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