Compact anechoic chamber system for antenna measurements

2022 ELE Engineering Design Project (MA02)

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Faculty Lab Coordinator

Marco Antoniades

Topic Category

Signal Processing / Communication

Preamble

Commercial anechoic chambers for characterising antenna performance are typically expensive and very large in size. A chamber for measuring smartphone antennas could easily cost more than a million dollars and span two stories in height. This has motivated the development of compact chambers having a similar quiet zone volume compared to a large chamber without sacrificing chamber performance. This project aims to design and build a low-cost anechoic chamber having a geodesic array of sensors capable of characterising full 3D MIMO performance that becomes increasingly relevant for 5G communications. This is a feature that multi-million dollars commercial chambers are currently incapable of doing, since MIMO performance is characterised in a plane.

Objective

The objective of this research project is to design and build a compact anechoic chamber system for antenna measurements in the frequency range of 800 MHz to 3 GHz, with a maximum size of less than 4m in any dimensions.

Partial Specifications

Antenna sensor specifications:
1. Dual-polarization with one port for each polarization (2 ports in total)
2. Frequency range: 800 MHz to 3 GHz
3. Port to port isolation: > 20 dB
4. Reflection coefficient: < −10 dB
5. Peak Gain: +6 dBi
6. Directivity: as high as possible
7. Dimensions: as small as possible

Chamber specifications:
1. A geodesic dome consisting of multiple panels and a rotating pedestal at the bottom.
2. Each panel will be lined with pyramidal foam absorbers, with the antenna sensor located at the center of each panel.

Suggested Approach

The students should become familiar with existing state-of-the-art compact near-field anechoic chamber designs for antenna characteristic measurements (including radiation patterns, gain, directivity, and radiation efficiency) by studying relevant research papers, books, and commercial online material. They should also become familiar with standard dual-polarized antenna designs offering high directivities, which will be used as the sampling sensors for the electromagnetic fields around the AUT. Features such as size, directivity, gain, radiation efficiency, and matching performance will be evaluated within industry-standard electromagnetic simulation software, leading to final designs which will be fabricated and tested.

Group Responsibilities

The group should work collaboratively as a team to define the specifications for each component of the system in order to achieve the overall objective of the project, which is to design and build a compact anechoic chamber system for antenna measurements. Each component will be designed separately, which will then be integrated to form a final working prototype of the compact anechoic chamber.

Student A Responsibilities

Dual-polarized antenna #1 design and fabrication

Student B Responsibilities

Dual-polarized antenna #2 design and fabrication

Student C Responsibilities

Geodesic anechoic chamber #1 design and characterization

Student D Responsibilities

Geodesic anechoic chamber #2 design and characterization

Course Co-requisites

ELE 861 – Microwave Engineering

To ALL EDP Students

Due to COVID-19 pandemic, in the event University is not open for in-class/in-lab activities during the Winter term, your EDP topic specifications, requirements, implementations, and assessment methods will be adjusted by your FLCs at their discretion.