Dual-Band High Impedance Surface With Mushroom-Type Cells Loaded by Symmetric Meandered Slots

A novel dual-band high impedance surface (HIS) with mushroom-type cells loaded by symmetric meandered slots is proposed. Two kinds of band-gap features: one for surface wave suppression and the other for high-impedance in-phase reflectivity, are realized for dual-band operation simultaneously. The characteristics of the meandering slotted high impedance surface (MS-HIS) are investigated by using finite-element full-wave analysis in this paper, which show that the two band gaps are separately produced by cross slots and meandering slots. It is revealed that the surface wave suppression band gaps can be used to reduce the backward radiations and prohibit the mutual couplings between two E-plane coupled microstrip antennas at two operational frequencies. When a plane wave obliquely illuminates the MS-HIS, the unique feature of triple resonant behavior is observed. Furthermore, a dual-band radar absorbing material (RAM) based on the MS-HIS is proposed. The absorbing performance is verified by simulations and waveguide measurements using C-band WR197 and X-band WR90 waveguides.