Radar absorber material (RAM) or microwave absorbers are designed to absorb electromagnetic radiation and are lined in anechoic chambers. They are made of fireproofed urethane foam loaded with carbon and cut into pyramid shapes of varying sizes. The pyramidal structure provides geometric matching to absorb incident radio frequencies. RAM absorbers are temperature resistant, fire retardant, and can withstand high power levels for long-term use in anechoic chambers to measure antenna patterns and create electromagnetic quiet zones.