Reflective frequency selective surface based on low-permittivity dielectric metamaterials

In this letter, the design of reflective frequency selective surface (RFSS) using low-permittivity dielectrics is proposed based on effective medium theory. The effective medium approach is based on quasi-static extension of the Maxwell-Garnett model. Unlike conventional RFSSs, such RFSS is composed of low-permittivity dielectrics rather than high-permittivity or metallic materials. By drilling periodic hole arrays in multi-layer continuum dielectric plates, strong electric and magnetic resonances are introduced to produce drastic changes in effective parameters, leading to impedance mismatch and band-stop response. The band-stop response can be tailored by adjusting the size and spacing of the unit cell. As an example, an RFSS with rectangular hole element is demonstrated at K-band. The mechanism is analyzed by presenting the effective electromagnetic parameters and dynamic field distributions. A prototype was fabricated and measured. Excellent agreements between measured and simulated results were obtained. The method can also be used to design RFSS in THz and optical frequencies.