Miniaturized Reconfigurable Rasorber for Intelligent Electromagnetic Protection

A miniaturized reconfigurable rasorber which is applied for intelligent electromagnetic protection is presented. The structure consists of a upper resistive layer, an air layer and a reconfigurable bandpass layer. In order to realize the miniaturization design of the unit-cell, the four arms of the resistive metal ring on the upper layer are folded as a composite S-shape. The unit-cell dimension of the FSR is
$0.066\lambda_{0} (\lambda_{0}$
is the wavelength of the minimum frequency of the absorption band in free space). PIN diodes are symmetrically mounted on the lower band-pass structure to achieve the reconfigurability of shield and band-pass mode from 3.22 to 4.5 GHz. The insertion loss in 3.67-4.15 GHz is less than 3 dB in band-pass mode and the minimum insertion loss reaches 0.41 dB at 3.88 GHz. The proposed structure can maintain wave absorption at both the two modes in 1-2.6 GHz, with reflection coefficient S11 of less than −10 dB and transmission coefficient S21 of less than −15dB. At the meanwhile, the FSR with a symmetrical design has the characteristic of polarization insensitivity. The proposed structure can be applied for intelligent electromagnetic protection of modern electronic systems.