Integration of an Equivalent Aperture Method into Full-wave Electromagnetic Simulation of Airborne Radomes

A method is provided for performing efficient, accurate, full-wave electromagnetic simulations of airborne radomes by representing the enclosed antenna with an equivalent aperture field distribution. In this case, the antenna and radome problems are essentially decoupled, and fine meshing details in the antenna region of the problem are eliminated. The equivalent aperture governing equations are discussed, and an algorithm for forming a representative aperture field distribution from far-field radiation patterns is provided. The success of the equivalent aperture method is demonstrated via an example problem. Equivalent aperture results are compared to full-wave simulations of a corresponding fully-detailed slot array antenna. For both the equivalent aperture and corresponding slot array antennas, a 2: 1 fineness ratio tangent ogive radome with dielectric constant of 7 and metallic tip is simulated to determine the effects on radiation patterns, loss, and boresight error. Radome insertion loss agreement is achieved to within 0.3 dB or better and boresight error agreement is achieved to within 0.05 deg or better in both elevation and azimuth scan planes for a significantly detuned radome wall. Both transmit-mode and receive-mode formulations of the full-wave radome analysis and their appropriate uses are described.