A frequency-independent inhomogeneous planar radome with high angular stability based on permittivity manipulating

Abstract

In this paper, an inhomogeneous planar radome (IPR) has been thoroughly investigated from an electromagnetic perspective. The inhomogeneity is considered to be an exponential function. Closed-form expressions have been derived for the transmission and reflection coefficients. A radome with frequency-independent response and angular stability up to 53° is achieved by manipulating the dielectric Permittivity Profile Variation (PPV) function with definite curvature. Implementation has been done with the use of the equivalent material theory (EMT). The optimal radome wall is prototyped by perforating the host medium continuously (which eliminates losses due to the discretization). An ultra-wide-band (3–18 GHz) free space measurement setup is used to characterize the frequency response of this prototype. Measurements are performed for both polarizations of TE and TM and various angles of the incidence. The results are in good agreement with the unit-cell full-wave simulations. The design procedure is generally described, which can be implemented for various electromagnetic and mechanical requirements.