基于花瓣形开槽可调高阻表面单元的S波段可重构表面波波导设计与仿真

Design and Simulation of the Reconfigurable Surface-wave Waveguide Based on Petal Slotted Tunable High Impedance Surface Cells in S Band

摘要:

基于高阻表面的表面波波导在微波系统中被广泛用于传输表面波能量或者导引表面波至别处，但大多数表面波波导都存在如下问题：其一，导波路径是固定不变的，不能依据实际情况实时改变导波路径；其二，工作频段都很高，几乎都在X波段或以上频段。这两个问题极大地限制了表面波波导的应用范围，尤其第一个问题意味着需要为每一条导波路径设计一个波导，将极大地提高设计加工成本。本文先设计了一个花瓣形开槽的正方形高阻单元，并加载了四个变容二极管（SMV1408），通过调整变容二极管的反向偏置电压从20V下降到0.2V，实现了在常用的S波段单元阻抗从约j390Ω增加至约j1710Ω；然后基于该可调高阻单元提出了可重构表面波波导概念，并通过HFSS仿真证明了该概念的可行性。该波导可以同时形成多条导波路径，并可实时调整导波路径；同时为了抑制表面波能量泄漏，利用我们之前的研究成果对导波路径的设计提出了相应的建议，仿真结果很好地验证了我们建议的有效性。

Abstract:

The surface-wave waveguide, based on the high impedance surface, is widely used to transform the surface-wave energy or to guide surface-waves along a constrained path. However, there still remain two issues for almost surface-wave waveguides. First, the guided-wave path is fixed, which will prevent changing the guided-wave path in real-time situation. Second, the working frequency band is usually high, which is in X band or higher frequency range. The two issues have limited the large-scale applications of the surface-wave waveguide, especially for the first one, which means that one has to design a waveguide for every guided-wave path, leading to the high cost. In this paper, a high-impedance square cell with petal slots attached to four varactors (SMV1408) is designed, its impedance value increases from j390Ω to j1710Ω in S band by decreasing the reverse bias voltage of varactor from 20V to 0.2V. Based on this tunable cell, we propose the concept of the reconfigurable surface-wave waveguide and its feasibility has been proved by HFSS. In the simulation, the proposed waveguide can provide multi-guided paths and the paths can be adjusted in real time; meanwhile, to prevent the energy leak of surface-waves, the guide-wave path is optimized by our previous achievements, and the effectiveness of our suggestions is verified well by the simulation results.