The Two-Port Transmission Method With Applications to Microstrip Phased Arrays

A novel method is presented to investigate substrate leaky and/or surface wave mode effects within microstrip antenna arrays. The proposed methodology provides accurate modal analysis for the array elements, while including all metallic and different material inclusions, regardless of geometrical shape. Furthermore, the proposed methodology is very general because it accounts for all phenomena and design requirements including arbitrary excitation of the antenna elements in amplitude and phase, the effect of the substrate modes, mutual coupling, and scan blindness. Substrate waves can be studied directly from the same setup with an operating microstrip phased array. One additional significant advantage of this approach is that interelement antenna array spacing can be larger than half a wavelength in the design of phased arrays, thus, overcoming heretofore limitations in the study of scan blindness.