Oblique Plane Wave Synthesis in Free Space and Over-Moded Waveguide

Plane wave generator (PWG) is a key equipment to test the radiation performance of wireless devices in the over-the-air (OTA) test. Though many types of PWGs have been reported, it is still a difficult task to generate oblique plane waves (PWs) to improve the range of impinging angles of arrival (AoAs) in the quiet zone for the PWG. In this work, a comparison of the capability to generate oblique incident plane waves using PWG in free space and in over-moded waveguide (WG) setups is studied. Two types of PWGs with similar size and the same quiet zone size are simulated and compared, one in the free space setup and the other one in the WG setup. The simulation results demonstrate that PWG in the WG setup has better angle expansion capability offered by reflection of WG, while the PWG in the free space setup can only effectively work within a very small angle range.