Y环单元FSS结构参数对频率特性的影响

Effects of Y loop element FSS structure parameter on frequency response

利用谱域分析法,从Y环单元的臂长、臂宽、缝宽、加载介质的厚度及介电常数等方面,研究了Y环单元频率选择表面(Frequency Selective Surface简称FSS)结构参数对其频率响应特性的影响;采用镀膜和光刻技术制备出了相应的实验件,并在微波暗室进行测试,测试值与计算值基本一致。结果表明:臂长主要影响中心频率,臂长从3.8 mm增大到4.7 mm时,中心频率从11.9 GHz下降到8.9 GHz;单元间距主要影响带宽,单元间距从0.3倍波长增大到0.5倍波长时,-3 dB带宽从3.2 GHz减小到1.0 GHz;臂宽和缝宽在影响中心频率的同时也影响带宽;介质加载主要使中心频率降低,但是中心频率并非随着介质层厚度的增加单调减小;加载介质的厚度和介电常数都影响中心频率,但中心频率对介电常数的变化更为敏感;介质加载也影响中心频率处的功率传输,如果对加载介质进行合理的匹配能改善FSS的传输特性。

Effects of the parameteristics of Y loop element on the frequency response characteristics of frequency selective surface （FSS） were studied by spectral domain method, especially in the thickness and permittivity of the loading dielectric. With filming technology and lithography, the corresponding FSS was produced. And the tests of it in the microwave darkroom were given. The agreement between the calculated and measured is good. The results show that, the arm length mainly influences the center frequency, which increases from 3.8 mm to 4. 7 mm, the center frequency decreases from 11.9 GHz to 8.9 GHz. The space between the elements mainly influences the bandwidth, which increases from 0.3 wavelength to 0.5 wavelength, the bandwidth decreases from 3.2 GHz to 1.0 GHz. The arm width and the slot width influence the center frequency as well as the bandwidth. The center frequency of FSS decreases along with the dielectric loading, but it does not decrease at all times. The center frequency is influenced by the dielectric thickness and dielectric permittivity, but the latter does much more. The dielectric loading can also influence the transmission power at the center frequency, the appropriate dielectric thickness and dielectric permittivity can stabilize the FSS transmission characteristics as the angle of incidence and the polarization are varied, and it can improve the transmission characteristics of FSS.