变容二极管可调谐频率选择表面斜入射特性分析

Analysis of Oblique Incident Characteristics of Varactor-Tunable Frequency Selective Surface

本文首先观察在电磁波斜入射情况下变容二极管可调谐频率选择表面的传输特性变化;接着采用等效电路方法分别分析频选传输特性变化原因及带宽补偿层的实现原理;最后将带宽补偿层添加在频率选择表面两侧,用于改善周期结构的斜入射传输特性。利用该方法设计的频率选择单元在TE和TM波0~60°的范围内,可以实现透波窗口传输极点频率9~18GHz的可调谐,且传输极点f0处透波率大于50%,添加带宽补偿层后不同电容状态下传输极点的插入损耗可以减小0.3~1.4dB。

In this Paper,the transmission characteristics of varactor-tunable frequency selective surface under the oblique incident electromagnetic wave is first observed.Then the reasons of the change and the principle of bandwidth compensation layer are analyzed with equivalent circuit method.Finally,the bandwidth compensation layer is placed on both sides of the frequency selective surface to improve the oblique incident transmission of periodic structure.The frequency selective surface designed with this method can tunable at the transmission pole frequency of 9~18GHz,and the transmittance at the transmission pole is greater than 50%,the insertion loss of transmission pole can be reduced 0.3~1.4dB by under different states of varactor diode by using the bandwidth compensation layer.