DirecRF

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Sponsored by Distinguished Professor Zoya Popovic and Assistant Research Professor Gregor Lasser

In academic and industrial research there is often a need to characterize the radiation emitted by electrical devices, such as the 3-dimensional radiation pattern of an antenna or the parasitic radiation pattern of a component from which it is critical to minimize radiation. This is typically done by measuring the power received by an antenna with known properties, at a variety of orientations relative to the device under test. Anechoic chambers are necessary for such measurements because microwave-frequency radiation would otherwise reflect from obstacles in the surrounding environment, obscuring results. It is convenient for antenna positioning to be automated because manual positioning is tedious and imprecise. Commercially-available antenna ranges can be far-field or near-field (compact), however these solutions may require large spaces and are expensive, making them impractical for some researchers.

The automated anechoic chamber is a major update and modification to a pre-existing 2 GHz–20 GHz anechoic chamber at CU Boulder that doesn’t have automated antenna positioning or power measurements. It enables radiation measurements at orientations that can be chosen with better than 1◦ of precision on each actuated axis, with minimal need for human interaction. The antenna under test and probe antenna can rotate in place to enable measurement of the power from the antenna under test over a sphere around it, with controllable polarization angle. Experiments can be controlled and results can be recorded and displayed through a Command Line Interface (CLI), allowing for quick and easy observation and interpretation of radiation properties. This product can facilitate research by faculty, graduate and undergraduate students at CU Boulder, as well as by visiting researchers from the defense and wireless communication industries who commonly rent out the anechoic chamber. While automated anechoic chambers are not a novel concept, this product is tuned to the specific use cases of CU Boulder faculty and therefore costs less than competing products; thus, it is an appealing solution for university departments and small companies with limited resources. Its software interface also makes it easy to execute measurement modalities that are useful to CU Boulder faculty and to digest and analyze their results, even for users with limited software and microwave experience.