Lan Yu, Xu Yuehang
School of Electronic Science and Engineering (National Exemplary School of Microelectronics), University of Electronic Science and Technology of China, Chengdu 611731, China.
Micromachines (Basel). 2018 Oct 20;9(10):531. doi: 10.3390/mi9100531.
In this paper, bending limit tests for one ultra-thin liquid crystal polymer (LCP) substrate (Rogers 3850) based on the mechanical properties of flexible microwave microstrip components are presented. First, a set of 50 Ω microstrip lines, a band-pass filter, and a stepped impedance filter in X-band, are designed by using double clapped LCPs with 50 μm thickness of substrate and 18 μm thickness of copper, which is fabricated by conventional photolithography. Then, the limit tests of the flexibility of the LCP microwave microstrip components are presented, and the range of the bending limit radius, from 1 mm to 0.75 mm, is demonstrated from the testing results. It is found that the cause for component failure is fracture of the copper (18 μm thickness) laminate, according to the bending limit test experiments. Finally, the analysis of the reasons for the collapse of the microwave components, under bending situations, is explored. The results from this work would be useful for further designs of the flexible microwave devices and systems on LCP substrates, with compact sizes and good performance.
本文基于柔性微波微带元件的机械性能，对一种超薄液晶聚合物（LCP）基板（罗杰斯3850）进行了弯曲极限测试。首先，使用厚度为50μm的基板和厚度为18μm的铜的双夹层LCP，通过传统光刻工艺制造了一组X波段的50Ω微带线、一个带通滤波器和一个阶梯阻抗滤波器。然后，进行了LCP微波微带元件的柔韧性极限测试，测试结果表明弯曲极限半径范围为1mm至0.75mm。根据弯曲极限测试实验发现，元件失效的原因是18μm厚的铜层压板断裂。最后，探讨了微波元件在弯曲情况下崩溃的原因分析。这项工作的结果将有助于进一步设计基于LCP基板的柔性微波器件和系统，这些器件和系统尺寸紧凑且性能良好。
