介绍了一种使用多触点MEMS开关实现的新型可调微波MEMS低通滤波器,应用MEMS制作工艺在石英衬底上实现滤波器结构.滤波器基于慢波共平面波导周期性结构,具有尺寸小、插损低、可与单片微波集成电路工艺兼容等优点。滤波器截止频率的大小取决于MEMS开关的状态。实验结果表明,当MEMS开关受到激励时,低通滤波器的3-dB截止频率从12.5GHz转换至6.1GHz,带内纹波小于0.5dB,带外抑制大于40dB,开关的驱动电压在25V左右。
A new type of tunable microwave microelectromechanical systems low-pass filters with MEMS switches is introduced and the structure has been realized on quartz substrate using MEMS fabrication technology. The filter based on slow-wave coplanar waveguide periodic structure exhibits excellent performance on small size, low insertion loss and is compatible with monolithic microwave integrated circuit technologies. The 3-dB cutoff frequency depends on the different states of MEMS switches. The tested results show that the passband ripple is less than 0. 5 dB and the out-of-band rejection is better than 40 dB when the 3-dB cutoff frequency is changed from 12. 5 GHz to 6. 1 GHz with the MEMS switches actuated. The driven voltages of the switches are around 25 V.