Anechoic Chamber

Location: University Shopping Plaza Suite 900
Headed by: Hussain Al-Rizzo
Funded by: NSF Epscor
Technical Specifications:

  • Tapered anechoic chamber design
  • Frequency range 400 MHz – 18 GHz
  • Minimum guaranteed performance voltage standing wave ratio (VSWR) of -35 dB at 400 MHz (see table below)
  • Manufactured by Cuming-Lehman Chambers
  • Anticipated completion date: April 2009



Systems Engineering’s newly designed radio frequency anechoic chamber will be used to house the equipment for performing measurements of antenna radiation patterns, electromagnetic compatibility (EMC) and radar cross section measurements.

An anechoic chamber is a shielded room designed to attenuate sound or electromagnetic energy. Anechoic chambers were originally used in the context of absorbing acoustic (sound) echoes caused by internal reflections of a room, but more recently anechoic chambers have also been used to provide a shielded environment for radio frequency (RF) and microwaves

An RF anechoic chamber is designed to suppress the electromagnetic wave energy of echoes: reflected electromagnetic waves, from the internal surfaces. Both types of chamber are constructed with echo suppression features and with effective isolation from the acoustic or RF noise present in the external environment. In a well-designed acoustic or RF anechoic chamber, the equipment under test receives acoustic, mechanical or RF signals from a signal source, a perfect chamber will not internally reflect these transmitted waves. This ensures the integrity of the subject being tested is not influenced by external or internal reflected noise.


Most anechoic chambers are enclosed in faraday cages in order to lessen outside electromagnetic interference. The inside of a radio frequency anechoic chamber is lined with large foam pyramids called radar absorbent material (RAM), that work to nullify the reflection of radiation back onto the sensors which would create errors in the results. Radar absorbent material in the form of foam absorbers is used in the UALR anechoic chamber.


Foam absorber is used as lining of anechoic chambers for electromagnetic radiation measurements. This material typically consists of a fireproofed urethane foam loaded with carbon black, and cut into long pyramids. The absorber is applied to the chamber walls with the tips of the pyramids pointing inward or toward the radar. As a radar wave strikes a pyramid, it experiences a gradual transition from free space at the tip of the pyramid to absorbing foam at the base.

Anechoic Chamber