R-Card fence applications for indoor anechoic chamber

It is shown in this paper that properly designed R-Card fences can be installed in indoor measurement facility to reduce the multipath signals in the chamber. The design is especially more effective when the transmit antenna is closer to the absorber wall. The traditional foam absorber works well when the angle of incidence is less than 50 degrees if the thickness is about 2 wavelengths. The R- Card fences greatly improve the chamber performance when the angle of incidence is greater than 50 degrees. Furthermore, it may be possible to use smaller size of absorber (less than 2 wavelengths) with the R-Card fence when the overall chamber size is limited. It is then possible to measure larger size of AUT/UUT in an existing chamber as well as extend the frequency range of the chamber to the lower end.