Increasing the bandwidth of coaxial aperture arrays in radar frequencies

Abstract

Arrays of coaxial cavities in a silver slab are an angle-independent frequency-selective structure in the optical wavelengths. We show that understanding major resonant effects can achieve a similar structure in the radar frequencies. We use a biperiodic boundary integral method to explain the resonances. We suggest a geometrical evolution of the coaxial cavities that presents an enhanced bandwidth under oblique incidence in TM polarization.