Measurement system for millimeter-wave antenna characterization

Published : 19 November 2021

Master 1 training period / 2022
Measurement system for millimeter-wave antenna characterization at IMEP-LAHC
Laboratory: IMEP-LaHC – MINATEC – Grenoble



Supervisors / contacts:
Pascal XAVIER (scientific supervisor) Phone: 04 56 52 95 69
Nicolas CORRAO (technical support) Phone: 04 56 52 94 69

Context and objectives:
The constant development of communication standards (LAN, 5G, 6G…) and the emergence of new applications based on wireless propagation (Internet of Things, RFID chips, automotive radar systems, radar imaging radar sensors …) bring new technical requirements. Designing innovative antenna devices in the RF and millimeter-wave (mmW) spectrum is one of the main fields of interest for researchers at IMEP-LaHC Lab. Consequently, there is a strong need of
measurement setups to test and evaluate antenna parameters. Such characterizations are challenging because they require specific environmental conditions (quiet zone, free of EM perturbations or reflections) associated with a dedicated acquisition system.

This kind of installation is already available on HYPER platform at IMEP-LaHC. An indoor antenna test range is installed in a fully anechoic chamber to eliminate all reflections from the walls. This setup provides a powerful and accurate far-field measurement solution, typically used up to 40GHz. Therefore, a RF analyzer coupled with a 3-axis positioning system is used to perform the 3D radiation pattern measurement of the antenna under test. However, as the frequency increases, new strengths have to be considered. For example, at millimeter-wave frequencies (typically above 50GHz), antenna size becomes smaller and antenna gain decreases. Thus, the device is more sensitive to its close environment (connectors, mechanical parts…) which can strongly impacts its radiation. Moreover, the large attenuation at these frequencies must be taken into account when designing the measurement setup (short interconnection paths, antenna as close as possible to circuitry…).

Our existing antenna test range can’t meet all these new requirements. Therefore, another measurement solution has to be developed and dedicated especially to millimeter-wave devices. With this new separate setup, user should be able to extract 3D (quasi-sphere) radiation pattern and
gain from miniaturized or integrated devices, operating in V band (50 – 75GHz) or W band (75- 110GHz). Antenna under test could be fed either with precision coaxial connector or with microelectronic probe. In both cases, a special attention will be given to the surrounding parts of the antenna, in order to reduce measurement error caused by unwanted reflections.

Description of the work:
The required measurement setup described above is already under construction. The main parts and components are indeed at disposal on HYPER platform. A new 2-axis positioning system has been designed and fabricated. This one is also available and ready to work. It can be easily controlled using dedicated computer and software tool.

This lab work consists in several tasks, including existing setup improvements, design of still missing mechanical parts, final developments and installation, tests and validation of the whole system and finally training of users. All this tasks will bring the student to improve its skills in electromagnetism (RF and millimeter-wave measurements), obviously focused on antenna characterization methods. Even if the main part of the setup already exists, a lot of mechanical
adjustments and assemblies as well as RF tests have to be done to complete the project.

The proposed lab work implies of course a strong teamwork.

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