EMAC

The ElectroMagnetic Anechoic Chamber (EMAC) is a 2,200 square foot facility that supports the research of faculty and graduate students by providing precision antenna and radar cross section measurements. In addition, the facility is a test-bed for a unique design in Compact Antenna Test Ranges (CATR).

With inside dimensions of 51 ft. (15.5m) by 26 ft. (7.9m) by 18 ft. (5.5m), ASU’s EMAC facility has one of the largest university-based anechoic chambers in the United States. The shielded room is lined with microwave absorbing material to greatly reduce the reflections, or echoes, of the test signals inside. This controlled environment simulates the conditions of “free space” that are suitable for testing antennas and scattering targets.

The March Microwave-designed Single-Plane Collimating Range (SPCR) is a curved, highly polished metal reflector that reshapes the spherical phasefronts produced by the system’s feed into high-quality cylindrical wavefronts in the test region. Cylindrical wave measurements are then transformed into the desired plane wave results via computer software. The primary advantage of the SPCR over conventional, fully collimating CATRs is a much larger quiet zone in the horizontal plane. ASU has the distinction of being the first to implement this cylindrical wave range configuration.

The SPCR reflector is specified by the manufacturer to operate from 2 GHz to 100 GHz. The EMAC facility currently has linearly polarized feed horns which cover frequencies from 500 MHz to 18 GHz.

Test targets are oriented with an Orbit azimuth-over-elevation positioner which is rated at 2500 lbs maximum vertical load and 2500 ft-lbs maximum bending moment. The positioner is driven with a Scientific Atlanta 4139 positioner controller.

The instrumentation at the EMAC facility is based on the HP8510C Vector Network Analyzer. Consequently, in addition to radiation and scattering patterns, all S-parameter based measurements can be performed. The frequency range of the instrumentation is from 10 MHz to 20 GHz.