Research And Design Of Distributed Filter Based On Thin Film Technology

With the application of the fifth generation mobile communication,the working band of the filter has entered the millimeter band.Since the lumped filter operates with large parasitic parameters in this band,the performance is greatly discounted,and the distributed parameter filter becomes an ideal choice.Conventional filter design circuits reflect unwanted signals back to the source through a stop band,which can have a devastating effect on system performance.The function of the absorption filter is that the stop band portion of the signal is absorbed rather than being reflected back to the signal source.Since the distribution parameter(distributed)filter operating in the microwave millimeter wave is small in volume,in order to ensure its stable performance,it requires higher precision in the manufacturing process.The thin film circuit process is characterized by a wide range of device parameters,high accuracy,good temperature and frequency characteristics,and can operate in the millimeter wave band.And the integration is higher,the size is smaller,and the cost is low.In this paper,the distributed filter is deeply studied based on the thin film process.Based on the research background of distributed filters,this paper designs three band-pass filters,including SIR structure,U-shaped structure and open-loop structure.The structural improvements and innovations are made on the basis of these three filters.To achieve better performance and smaller size.Then,based on the interdigitation filter,an interdigital coupling structure is constructed,and a bandpass filter with tunable absolute bandwidth is designed.Then introduced a new distributed absorption filter,which has stronger out-of-band absorption capability than the traditional absorption filter,and designed two distributed absorption filters for verification,verification results and theoretical results.Consistent.