Anechoic Chamber for Microwave Antenna Test With Pyramids Arranged to Extend Ground Plane
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-08
For testing an antenna inside an anechoic chamber, the wall-to-floor edge of the chamber is padded with microwave-absorbing foam to form a smooth transition between the floor and the wall. This modification reduces reflections and improves the test. Antennas are often tested in an anechoic chamber that has its walls lined with pyramids of a foam material that contains carbon or other microwave-absorbing particles. In a typical test, the antenna is excited at a test frequency and the energy from the antenna is measured. The test values are used in formulas that are based on an infinite ground plane and no reflections. It has been found that microwave reflections occur at the edge of the floor of the typical chamber where there is a vertical separation of a few inches between the floor and the peaks of the first row of pyramids.