A waveguide modulator using switchable frequency selective surface (FSS) for amplitude shift keying modulation (ASK) at super high frequency (SHF) has been presented. The FSS consists of rectangular loop aperture elements with two PIN diodes at 180^∘ intervals on every unit cell across the aperture. A minimum transmission isolation of 30 dB has been achieved at resonance frequency when the diodes are switched between ON and OFF states. The PIN diode parameters are modeled using Keysight’s Advanced Design System (ADS) software to find the missing value of inductance and match the results presented in its datasheet. The proposed FSS modulator can operate either for transverse electric (TE) or transverse magnetic (TM) polarizations subject to the positioning of the incident wave due to its rectangular geometry. Positive direct current (DC) biasing is introduced from the front while negative DC biasing has been connected on the back-side of the unit cell FSS. Both the diodes are employed orthogonal to the principal axis of the FSS to reduce the impact of negative bias-line on overall frequency response. Both simulation and measured results have been presented.

已经提出了使用可切换频率选择表面（FSS）以超高频（SHF）进行幅度移位键控调制（ASK）的波导调制器。FSS由矩形环形光圈元件和两个^180∘的PIN二极管组成跨孔的每个单位单元的间隔。当二极管在ON和OFF状态之间切换时，在谐振频率上已实现30 dB的最小传输隔离。使用是德科技的高级设计系统（ADS）软件对PIN二极管参数进行建模，以找到电感的缺失值并使其数据表中的结果相匹配。所提出的FSS调制器由于其矩形几何形状而可以针对横向电（TE）或横向磁（TM）极化而操作，这取决于入射波的定位。正直流（DC）偏置从正面引入，而负DC偏置已连接到单元电池FSS的背面。两个二极管均正交于FSS主轴使用，以减少负偏置线对整体频率响应的影响。仿真和测量结果均已展示。