Inside a Semi-Anechoic Chamber: Wireless RF Performance and Validation Testing

Suppose you have a wireless device that you’re developing. Or you’re a service provider, and you’re comparing various wireless devices that you want to deploy in the field. You’ve performed your own testing on these devices, but you need an unbiased third party to provide test results for your marketing or purchasing needs.

Wireless devices can be tested with a variety of professional equipment, such as an anechoic chamber, a semi-anechoic chamber or a test house.

In this blog post, I’ll discuss scenarios in which you would want to get testing done in a semi-anechoic chamber, and I’ll also show you Kyrio’s semi-anechoic chamber.

What Is a Semi-Anechoic Chamber?

A semi-anechoic chamber is an enclosure that is shielded from outside interference and is designed internally to dampen reflections of RF transmissions. Semi-anechoic chambers typically give measurements in two dimensions from the sides of the device.

The platform also includes devices for simulating wireless stations, access points, attenuation and interference. Traffic generation software is typically used to measure traffic throughput and monitoring tools are used for data collection and evaluation.

You can take a look at Kyrio’s semi-anechoic chamber in the following video:


What’s the Difference Between a Semi-Anechoic Chamber and an Anechoic Chamber?

Whereas an anechoic chamber provides measurements in three dimensions (from the top, bottom and sides), semi-anechoic chambers typically give measurements in two dimensions (from the sides of the device). A fully anechoic chamber is designed to absorb reflections inside the box, and a semi-anechoic chamber dampens them more like would occur in a large room.

The semi-anechoic chamber is designed to test devices for real world scenarios. This testing can be performed in a more uncontrolled environment like a test house, which we will learn more about in a future blog post. The chamber, however, is a controlled environment, where the tests are consistent and repeatable.

When Does It Make Sense to Get Testing Done in a Semi-Anechoic Chamber?

There are several situations where it makes sense to get your device tested in a semi-anechoic chamber:

  • Isolated environment from interference—The chamber eliminates outside interference, which is unpredictable and varies greatly.
  • Controlled traffic based on type or amount—Traffic generation software allows you to vary the type of traffic (voice, video, data) and the amount.
  • Repeatable results—Wireless devices can be inherently unstable, causing inconsistent results. The more stable the test environment, the more consistent the results.
  • Controlled interference—When we want to test the device against interference, we can control what type and how much.
  • Range capabilities—We use attenuation of the signal to simulate distance.
  • Directionality—We use a turntable to rotate the device during testing to determine directional sensitivity.

What Does a Semi-Anechoic Chamber Measure?

This platform is typically used for measuring throughput, Received Signal Strength Indicator (RSSI) and Modulation and Coding Scheme (MCS). These values can be used to describe the behavior of a device under various conditions. This data, in turn, can be used to show the performance of a device or for a comparative analysis across multiple devices. You can also see thresholds when a device roams or changes to a different channel for a better signal.

What Types of Tests Can Be Performed in a Semi-Anechoic Chamber?

  • Performance testing
  • Characterization
  • Antenna pattern
  • Interference testing
  • Mesh testing
  • Roaming

I hope this post has given you a better understanding of the semi-anechoic chamber and whether this piece of equipment is a fit for your needs. To learn more, download our sample semi-anechoic chamber test report below.

Watch the Video Now


For manufacturers and service providers, Kyrio accelerates and deploys new network innovations into the ecosystem. Backed by the power of CableLabs, Kyrio sets technology on a path to commercialization, enabling not just today but tomorrow’s communication.