Theory of ESPAR Design With Their Implementation in Large Arrays

A generalized formulation as well as a simple design approach is presented for electronically steerable parasitic array radiators (ESPAR). Based on the presented design procedure, a low-cost rectangular dielectric resonator parasitic phased array antenna is designed. An E-plane linear dielectric resonator phased array coupled to symmetric narrow slot apertures is investigated. The driven element is mutually coupled to the parasitic elements and reactive loads are utilized to control the phase to achieve a particular beam scanning direction. The use of low-cost reactive loads instead of expensive conventional phase shifters allows for more economic fabrication. Based on this design, a five elements planar array is designed and measured. In addition, a large array using ESPAR subarrays is presented.