In recent years, there has been an increased need for testing active RF antenna arrays and radar systems at high power. Since absorbers work by transforming electromagnetic energy into thermal energy, there is a danger that in the presence of high fields, the absorber will reach temperatures that will cause it to ignite. When companies make a considerable financial investment with an absorber lined test chamber, they are also committed to protecting their equipment and the safety of their personnel. To address these concerns, ETS-Lindgren have developed a wide range of high power absorbers for RF and Microwave applications.
To develop these high power absorbers, ETS engineers started the research by collecting temperature data for their polyurethane absorber under varying field strengths at 12.4 GHz, both on the surface and inside the absorber to get a thorough understanding of the entire piece of the absorber. Several effects impact the absorber's internal temperature for the same incident field level at the front of the absorber, such as the antenna test distance to the absorber, the shape of the absorber pyramid, and the measurement frequency. This research provided greater insight into the heat dissipation and temperature distribution inside the absorber. After validating the simulation models, the power handling capability of the absorbers can be calculated.
Among the key findings of the R&D, the ETS team learned that an absorber with a slender profile provides improved power handling capabilities and that applying forced air at a relatively low flow rate can significantly decrease the absorber temperature. More information on this research may be found in the following papers presented at the Antenna Measurement Techniques Association (AMTA) symposiums: "Multiphysics Analysis of RF Pyramidal Absorbers" and "Surface and Internal Temperature versus Incident Field Measurements of Polyurethane Based Absorbers in the Ku Band."
With over 10,000 enclosure installations globally, ETS-Lindgren is a leader in the design and installation of anechoic chambers for EMC and RF test applications, including per the military and commercial standards MIL-STD-461, ANSI C63.4, CISPR 16 and CISPR 25. This high power absorber for RF and Microwave applications is manufactured at ETS-Lindgren's facility in the United States and available for installations worldwide. To ensure high quality, each piece of the absorber is tested and serialized prior to shipment.
Click here to view ETS Lindgren's RF absorbers portfolio.
