Salisbury screen absorber with angular and polarisation insensitive resonant frequency

In this paper we report on a new Salisbury screen absorber design which resonates at a frequency independent of the polarisation and angle of the incident signal. This is achieved by exploiting the electromagnetic scattering behaviour of a high impedance surface (HIS) which consists of a grounded array of slot loaded rectangular patch elements. The HIS was designed to provide scan compensation over the angular range 0deg to 40deg by reflecting the incident signals in a phase conjugate relationship with respect to the change in the electrical spacing between the ground plane and a thin 400 Omega/square resistive screen which is placed close to the surface of the periodic array. Numerical predictions of the reflectivity are shown to closely match bi-static measured results for both TE and TM polarised signals over the frequency range 8 - 12 GHz.