Design And Implementation Of High Selective Fss Rasorber With Transmissive And Absorptive Response To The Radome

The rasorber technology can enable the airborne antenna to communicate normally in the working frequency band,while realizing the wave absorption in the threatening band,and effectively reduce the bistation RCS of the antenna.The key issue for highly selective rasorber is how to achieve fast roll off performance in absorbing / transmitting band.Therefore,this paper mainly studies the design method of highly selective rasorber.Firstly,based on the two-port network theory,a fast design method of rasorber is obtained.The indicators are divided into each function layer,and the performance of each layer is designed separately to achieve the purpose of quickly designing the rasorber.Based on the theory of the transmission line,the equivalent circuit of three bandpass filters which with different transfer function poles and zeros' relative position are established,design three kinds of basic transmission modes' transmission layer with highly selective,including a low-frequency transmission high-frequency reflection,a high-frequency transmission low-frequency reflection and intermediate-frequency transmission two-side frequency reflection.The relative transition bandwidths of the three transmission layers are less than15%.Then according to the three different kinds of bandpass filters mentioned above,we add a loss mechanism to convert reflection into absorption.After that,we design and implement three kinds of basic transmission modes' absorbing layer,including a low-frequency transmission high-frequency absorption with a relative transition bandwidth of 4%,a highfrequency transmission low-frequency absorption with a relative transition bandwidth of 7%and a intermediate-frequency transmission two-side frequency absorption,its relative transition bandwidths of the left and right sides are 26% and 7% respectively.Finally,we simulate and optimize composite structure combining the absorbing layer with the transmission layer.A highly selective rasorber with a center frequency at 8 GHz is obtained.Compared with the rasorber using the traditional bandpass filter as the transparent layer,the relative transition bandwidths on the left and right sides of the rasorber are shortened by 33% and 61% respectively,and the absorbing bandwidth is widened by 39%.Combined with ADS circuit simulation to fit its different curves,these results are consistent with full-wave simulation.The experimental test results are in good agreements simulation,and these results show that scheme is correct.