Absorber-loaded planar waveguide array antenna for compact range application

With the aim of reducing the interaction between the compact range antenna and the test horn antenna, 2 mm-thick absorbers were loaded on the whole surface of the waveguide array, and the slot number of each WRJ-120 waveguide is reduced to 29 from 57 expecting reduced mutual coupling between the adjoining slots. Experiments at 12 GHz were conducted under the compact range and open-air circumstances, and good agreement was obtained though some difference was found at some regions. Suppression of field distribution deviation (amplitude and phase), frequency property improvement, and validity verification with slightly larger antennas (up to 6O cm in aperture dimension) are the problems to be solved.