Authors: Vince Rodriguez, Zhong Chen
Publication: AMTA 2020
Available on November 2, 2020 at AMTA 2020 Virtual Symposium
Abstract—There have been a number of numerical analyses of RF absorber. These however, tend to focus on the reflectivity of the material not on the radar cross section (RCS) that it presents. Brumley studied the RCS of RF absorbers as a way to estimate the background RCS of anechoic ranges . The study was done empirically, doing measurements of the RF absorber, and looking at the RCS of different pyramids, with and without paint. Brumley presents some potential ways of improving the RCS signature of the range thus reducing the background RCS of the site. In this paper the suggestions presented by Brumley are revisited. Specifically, his recommendation for the so-called twisted pyramid configuration which he was unable to measure due to the lack of absorber for him to use in the test. In addition to the twisted pyramid, Brumley’s approach of inserting smaller pyramids in the valleys of a larger pyramidal arrangement to reduce the edges parallel to the incoming wave are also presented. The numerical studies are done using time domain techniques as well as frequency domain techniques. The results validate the data and the suggestions presented in 
 S. A. Brumley, "Improving the Performance of Anechoic Absorbers," in Proceedings of the 10th Annual meeting and Symposium of teh Antenna Measurement techniques Association (AMTA 1988), Atlanta, GA , Sep 12-16, 1988.