针对在工程研制阶段隐身雷达罩与频率选择表面(FSS)间的空气隙引起的隐身雷达罩传输性能劣化问题, 设计了一种具有低空气隙敏感度的新型雪花环状单元频率选择表面以降低空气隙的影响。采用模式匹配法进行了FSS理论仿真。为了进行对比分析, 针对假定技术指标分别给出新型单元FSS和Y环单元FSS的最优化设计结构, 采用光刻工艺制备出等效FSS平板样件, 在微波暗室中采用自由空间法测试其传输性能以验证设计。仿真和测试结果一致表明: 新型雪花单元FSS在很大的空气隙内(190~6 500 μm)均满足技术指标, 优于Y环FSS的最大空气隙范围(320~1 900 μm)。最后, 简要分析了雪花单元FSS设计的优点。分析结果显示, 新型雪花单元FSS在满足隐身雷达罩常规技术指标的前提下, 具有较低的空气隙敏感度, 可在工程试验阶段用于FSS的研制。

As the transmission properties of Frequency Selective Surfaces(FSS) will get worse because of the air gaps between FSS and original radome in the experimental stages, a novel snow loop element FSS was designed to reduce the effect of air gaps. The theoretical simulation was performed by using the mode matching method. For contrast, the best FSS structure designs of the novel snow loop element and Y loop element for the assumed qualification were chosen out respectively. The equivalent FSS sample plates were fabricated by using photolithographiy, and the transmission properties were tested in a microwave dark room to check the simulation results. Both the calculating and the testing results show that the novel element FSS meets the transmission request in a quite wide air gap range (190-6 500 μm), which is much better than the best Y loop design(320-1 900 μm). Advantages of this new type snow loop element FSS were briefly analyzed. It demonstrates that the snow loop FSS has very low sensitivity to the air gaps, which provides a new method for the FSS study in the experimental stages.