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提出了一种基于MEMS开关的射频衰减器设计方案。首先对整体电路的基础结构进行了设计,选择以CPW(共面波导)为传输线,接触式MEMS开关作控制器件,同时以开关中的电容作为断路时的平衡电容进行Q值匹配;其次,通过理论推导与计算得到了波导的截面尺寸;然后按所需衰减量计算T型网络各个电阻的阻值大小。再按照计算值在CST微波工作室中建模仿真,对比单级衰减和展频二级衰减的S参数,可以发现,在Q值匹配后的电路中,射频信号可以在更宽的频段内保持稳定衰减。最后通过UV-LIGA技术结合氧化钽电阻工艺对衰减器进行了样片试制与结果测试。结果表明,通过Q值匹配可以扩展衰减器的工作频段,为高频信号的稳定衰减提出了一种可行性方案。
A design of RF attenuator based on MEMS switch is proposed. First of all, the design of the basic structure of the overall circuit, choose to CPW (coplanar waveguide) for the transmission line, contact-type MEMS switch for the control device, while the switch capacitor as a balanced capacitance Q-value matching; Second, Theoretical derivation and calculation of the waveguide cross-sectional size; and then calculate the required attenuation of T-type resistance of the network size. Then according to the calculated values in the CST microwave studio modeling and simulation, comparing the single-stage attenuation and spread spectrum two-stage attenuation of the S parameters can be found in the Q value matching circuit, the RF signal can be maintained in a wider frequency band Steady decay. Finally, the attenuator was tested by UV-LIGA combined with tantalum resistance process. The results show that the operating band of the attenuator can be extended by Q matching, and a feasible scheme is proposed for the stable attenuation of high frequency signals.