五位分布式MEMS传输线移相器的优化设计

通过在共面波导传输线上周期性地加载分布电容,外加驱动电压改变电容值,实现分布式MEMS传输线移相器。从三个方面优化了五位分布式MEMS传输线移相器的设计:一是分别设计了11.25°和22.5°两种微桥,单元在Ka波段的插入损耗均大于-0.8 dB,回波损耗均小于-15 dB,相移精度小于0.4°,新的五位移相器以2种单元、19个微桥的结构替代了传统单一单元、31个微桥的结构,可减少微桥的总数;二是CPW传输线采用折叠布局,通过共用部分地线,移相器平面尺寸减小至1.81 mm×3.84 mm,相比传统五位分布式移相器,面积减小了56%,实现了器件的小型化;三是设计了一种新型的直流偏置结构,结构简单、工艺容易实现。

Optimized Design of 5-bit Distributed MEMS Transmission Line Phase Shifters

The distributed MEMS transmission line phase shifter was realized through a coplanar waveguide transmission line loaded periodically with distributed capacitors and external driving voltage control of the capacitance value.The design of the 5-bit distributed MEMS transmission line phase shifter was optimized from three aspects.Firstly,two kinds of the micro bridge of 11.25° and 22.5° were designed respectively.The simulation results show that the insertion loss is more than-0.8 dB,the return loss is less than-15 dB,and the phase error is less than 0.4° at Ka-band of the two units.The new 5-bit phase shifter was built by 19 micro bridges in 2 units instead of the traditional single unit 31 micro bridges,so the total number of the micro bridges was greatly decreased.Secondly,using the novel folded CPW transmission line layout,the CPW transmission line can make full use of the common ground plane,and the layout area of the phase shifter is reduced to 1.81 mm×3.84 mm.Compared with the traditional 5-bit distributed phase shifter,the area is decreased by 56% to realize the miniaturization of the device.Thirdly,a new simple DC-bias structure with easy processes was designed.