System Overview
The microwave anechoic chamber supports S/C/X/Ku-band operation (2 GHz–18 GHz), enabling accurate radiation pattern and gain measurements in a controlled free-space environment. The antenna-under-test (AUT) is mounted on a positioner system (mmWave Test Solutions) with fine angular control along the θ and φ axes, enabling 3D pattern measurement capabilities.
- Frequency of operation: 2 GHz – 18 GHz
- Coaxial cable for AUT: 2.92 mm
- Maximum weight (antenna + mount): 30 kg
To help plan measurements, consider the following approximate times assuming 1° angular resolution and 101 frequency points. Actual measurement duration may vary depending on software parameters and setup.
- Single 2D Cut: 5-10 min
- 3D Pattern: 2+ hr
Creating a Mount for the AUT
Introduction
There are 2 options for mounting the AUT to the positioner:
- The AUT is mounted onto an existing stainless steel jig that interfaces with the positioner system (recommended). This approach minimizes the amount material needed for producing the mount and results in a more rigid and stable structure. The jig also makes it easy to mount/dismount the AUT.
- Mount the AUT directly onto the positioner platform. This option should only be considered if the AUT is heavy and the combination of that with the jig would surpass the 30 kg limit, or, if the jig interferes with the space required to mount the AUT.
Generally, your mount should consist of 3 parts:
- Base with screw holes (unthreaded) to mount the AUT onto the antenna positioner
- Pillars to hold the AUT at a particular height
- Platform for the AUT to sit on
Mount Design: Option #1 (Recommended)
The recommended screw hole dimensions and spacings are shown in the image below:
The antenna may be oriented in any desired configuration. However, it must be positioned such that its physical center is located at a height of 304.8 mm (1 ft) above the positioner platform. This ensures proper alignment with the positioner’s center of rotation. Due to the added height from the stainless steel jig, the mount needs to hold the AUT 147 mm above the jig. While it does not have to be exact, the antenna should be positioned as close to this height as possible, especially if the user is planning to perform measurements in various cuts or perform a 3D pattern measurement.
It is important that the base is around 5 mm-thick to ensure that it may be held securely by the jig. It is also a good idea to add slots in the base for pillars to fit to provide extra support for the pillars. See this example:
This is an example of the overall (assembled) mount:
Please see the Resources section for sample 3D model files.
Mount Design: Option #2
The same information discussed for option #1 applies here, except for the following modifications:
- The height of the pillars used to support the AUT must be modified accordingly to account for the lost height which the stainless steel jig provided. Recall, the AUT must be phyiscally centred 304.8 mm above the positoner platform.
- The screw hole diameter should be 5.35 mm
- The screw hole spacing should be 40.65 mm (centre to centre)
How to Perform a Measurement
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