The Design of High Selectivity Reflectionless Filters Based on Twofold Structure

Modern communication systems place high demands on filter performance in complex communication environments, especially in suppressing out-of-band interference and improving frequency selectivity. Since conventional filters reflect signals outside the target frequency band, resulting in lower linearity of the receiver and increasing the complexity of the front-end design, it is important to design a reflection-free filter that can effectively select the target frequency band and suppress the reflection of out-of-band signals in order to improve the performance of the system.In this paper, a reflectionless filter is designed based on the twofold network structure and the topology of elliptic filter, which greatly improves the selectivity and stability of the communication system. Experimental results show that the filter is able to eliminate out-of-band signal reflections while maintaining high selectivity, which is highly consistent with theoretical predictions. This design provides new ideas and effective technical references for solving key challenges in modern communications.