Research On Design And Fabrication Of Extensible Flexible RF Passive Filter

The development of intelligent and integrated extensible flexible devices requires that the functional units of "sensing,storage,computing and transmission" of integrated devices have extensible flexibility.However,there is still a lack of systematic research on flexible extensible RF devices for sensing signal transmission.As an important RF frontend device,filter has a significant impact on the performance of RF circuits such as wireless signal transceiver module.Therefore,the realization of extensible flexible RF filter with extensible flexibility and stable performance in the event of deformation is of great significance to the development of extensible flexible integrated devices.Based on the analysis of the research status of RF passive filters,this thesis focuses on the flexibility and extensibility of microstrip passive filters.At present,there are relatively few studies on flexible and extensible microstrip filters,and most of them are designed using novel materials.From the perspective of structure design,according to the working principle of different microstrip passive filter components,two flexible and extensible passive filters are designed and fabricated respectively.The specific research contents are as follows.(1)According to the structural characteristics of microstrip devices,the limitations of the ground plane structure of traditional microstrip devices in realizing the extensibility and flexibility of devices are analyzed,and a metal ground plane design based on patterned structure is proposed.Based on the related research results of finite ground plane microstrip line,the influence of patterning parameters of metal ground plane of microstrip structure on the basic performance of microstrip structure is analyzed,which provides theoretical support for subsequent device design.(2)An extensible flexible microstrip stepped impedance low-pass filter based on finite ground plane is designed and fabricated.Based on the basic microstrip stepped impedance low-pass filter structure,combined with serpentine guide band design and patterned finite ground plane,a low-pass filter with extensible flexibility is constructed on a flexible substrate.The experimental results show that when the tensile deformation reaches 0%,20%and 40%,the cut-off frequencies of the flexible extensible microstrip low-pass filter are 3.09 GHz,3.06 GHz and 3.02 GHz respectively,and the change rate is less than 3%.The loss in passband is less than 1 dB,and the stopband rejection is greater than 20 dB.(3)An extensible flexible microstrip coupled open resonant ring bandpass filter based on coupling compensation is designed and fabricated.Inspired by the equivalent circuit of coupled resonant ring,a flexible and extensible design scheme of microstrip bandpass filter based on coupled compensation capacitor is proposed,and the patterned design method of bandpass filter circuit and metal grounding plate is studied.The experimental results show that when the tensile deformation reaches 0%,10%and 20%respectively,the center frequency is 0.990 GHz,0.988 GHz and 0.990 GHz,the passband bandwidth is 42 MHz,39 MHz and 43 MHz,the change rate of center frequency is less than 1%,and the change rate of passband bandwidth is less than 10%.The loss in passband is less than 2.5 dB,the return loss is more than 10 dB,and the stopband rejection is more than 10 dB.