Projects:2020s2-7112 Mechanically steerable parasitic array antenna for the Internet of Things
Parasitic array antennas provide a relatively simple solution for beam steering over 360 degrees in the horizontal plane. This can help scanning the environment to find users, or detect RFID tags and connected objects. It can also be used to optimize the signal transmitted or received from a moving user in a room, for example.This project will consider the conceptualisation, design and optimisation of a so-called parasitic array antenna that can be mechanically reconfigured through movement of the parasitic elements. The concept will build up on early prototypes and improve the concept to allow steering the antenna beam more efficiently. The project will use state-of-the art simulation electromagnetic simulation tools, and the selected design will be fabricated and tested.
Introduction
In this project we will investigate the properties of dielectric resonator antennas (DRAs) and design a mechanically steerable DRA-driven parasitic array antenna for the internet of things. Mechanical steering is chosen because of the low cost and high efficiency. The DRA components will be 3D printed using dielectric material, which also helps to keep costs low.
Project team
Project students
- Nikolay Burdakov
- Anna Ragg
Supervisors
- Professor Christophe Fumeaux
- Dr Shengjian (Jammy) Chen
Objectives
The aim of the project is to design, fabricate and test a mechanically steerable antenna for the internet of things, using a dielectric resonator antenna-driven parasitic array.
Background
High gain antennas
Omnidirectional antennas transmit or receive equal power in every direction in a plane. The opposite of these are high gain antennas, which transmit or receive most of their power in a specific direction. High-gain antennas involve a trade-off between increasing power in the direction of gain, and limiting the angles at which power is directed.
Parasitic arrays
Parasitic arrays involve a driven element, and up several parasitic directors and reflectors that cause constructive interference in the direction of desired gain, and destructive interference in other directions. They are a common way of implementing highly directive antennas. Parasitic arrays will be used in this project to direct beams.
Steerable antennas
To compensate for the limited beam width of high gain antennas, beam steering can be implemented to change the direction of gain. A common implementation of beam steering uses the phased array. Phased arrays have advantages: they are precise and can change direction quickly. However, they are computationally and physically expensive and have a limited range of steering angles, so are not appropriate for all applications.
Mechanically steerable antennas are generally cheaper and simpler than phased arrays. This project aims to implement mechanically steerable antennas that are more suitable than phased arrays for some applications in the Internet of Things.
Dielectric resonator antennas
Dielectric resonator antennas (DRAs) rely on standing waves at resonant frequency in a non-conductive dielectric material. They are useful for high-frequency applications, because there is no electrical loss in the dielectric material, and electrical losses can increase exponentially with rising frequency. DRAs can be realised using 3D printed dielectrics, which means they can be highly designable and customisable.
Mechanically steerable DRA-driven parasitic arrays
Mechanically steerable parasitic arrays have been implemented, as well as mechanically steerable DRAs. However, to our knowledge, no mechanically-steerable DRA-driven parasitic array has been designed before, so the results will be first-of-a-kind.
Method
Design process
The design process consisted of the following stages:
- Tune DR feed to 2.45 GHz and change to hemisphere
- Simulate and optimise for gain
- Fabricate
- Test and interpret results
Simulations
Simulations were conducted in CST. An iterative process was used, with one parameter being varied at a time, and the value resulting in highest gain being chosen.
Fabrication
[[File:Dielectric ellipsoid ante
Testing
The reflection coefficient of the fabricated antennas were tested using a a network analyser. Gain testing was then conducted at the tuned frequency in an anechoic chamber.
