Bandwidth Enhancement for Parallel Feeding Networks by Regulating Transmission Line Lengths

摘要

Here, an approach to enhance the impedance bandwidth of antenna arrays fed by a parallel feeding network is introduced and elaborated. Through regulating the lengths of each segment of the transmission lines between two adjacent T-junctions in the parallel feeding network, the bandwidth can be expanded, and the reflection can perform symmetrical response around the central frequency. A simplified and ideal circuit model for the analysis is illustrated, and recursive expressions are derived for the design. Based on the numerical results of the expressions, some concise and practicable rules are obtained and verified on a 4×4 array. In addition, aT-junction structure with flexible directions of branches is proposed as key components to exemplify the implementation of the microstrip feeding network.