Scale model helicopter antenna pattern measurements at ASU´s EMAC Facility

The ElectroMagnetic Anechoic Chamber (EMAC) facility has been in operation at Arizona State University (ASU) since 1988. In addition to providing experimental verification for theoretical prediction of radiation and scattering targets, this multi-purpose facility acts as a testbed for a unique, semicompact antenna test range. Antenna patterns of a scale model helicopter have been measured at 500 MHz and compared to Numerical Electromagnetics Code (NEC) prediction. These measurements demonstrate that accurate antenna patterns can be measured at frequencies much lower than expected according to the conventional wisdom concerning rectangular anechoic chambers and compact ranges. Measurements made at EMAC of a scale model helicopter at UHF demonstrate remarkable agreement with theoretical prediction, particularly in the case of the electrically small reflector, absorber, and chamber.<>