Independently reconfigurable multiband high impedance surface for L, C, X and Ku Radar Bands

In this paper, a novel reconfigurable multiband high impedance surface (HIS) is introduced which is based on employing simple patch-like elements with “off the shelf” varactor diodes and PIN switching diodes in a multilayer unit cell configuration to achieve reconfigurable zero-reflection phase bands at L, C, X and Ku radar bands. The proposed HIS structure consists of three individual layers of FR4 substrates stacked up on top of each other with vacuum gap of 1 mm. The bottom layer (L/X band) employs Toshiba 1SV245 varactor diodes with variable capacitance values from 4.55 pF to 0.6 pF. The middle layer (C band) employs Micrometrics Silicon Hyperabrupt varactor diodes with variable capacitance values from 0.8 pF to 0.2 pF. The top layer (Ku band) uses ON/OFF PIN switching diodes. The overall performance of the proposed reconfigurable HIS has been simulated using CST MWS and it has shown independently reconfigurable bands in L, C and Ku bands with partial reconfigurability in X band. The simulated tuneable effective bandwidth is from 0.93 GHz to 2.47 GHz for L band and from 5.78 GHz to 7.02 GHz for C band. The switchable bands for Ku band have been also observed at 12.1 GHz and 14.8 GHz. The overall unit cell structure has a thickness of 3.8 mm and periodicity of 10 mm.