Design of a novel open rectangular ring resonator bandpass filter

In this paper, a microstrip bandpass filter with a new open rectangular ring structure as resonator is designed. The filter uses ceramic medium as the substrate,and the resonant ring is folded on the basis of the traditional open ring, which further reduces the size of the filter without affecting the resonant frequency. The working frequency of the filter is 20GHz, the bandwidth is 2GHz, the loss in passband is less than 1dB, and the reflection in band is more than 15dB.In the process of filter design, using BP neural network to assist calculation can effectively reduce the design time and improve the design efficiency. The simulation performance of the filter is good, and the size is only about 5mm * 5mm, which can meet the standard of machining and measurement.