An Octave-Bandwidth Dual-Function Array

This work presents the design of an octave bandwidth array, using stacked microstrip patches fed through aperture coupling. The array features the use of metallic cavities and fences in the elements to reduce surface wave propagation in the substrates and improve the front to back ratio. The $\mathbf{4}\times \mathbf{4}$ array provides stable radiation patterns with frequency, with a gain of 17.1 dB at 4 GHz, and operating from 2 to 4 GHz with a VSWR<2.