A Novel Parallel-Series Feeding Network Based on Three-Way Power Divider for Microstrip Antenna Array

A novel parallel-series feeding network for microstrip antenna arrays has been presented. A three-way power divider is utilized to connect the subarrays with the series-fed transmission lines. The proposed power divider is composed of seven transmission lines with different characteristic impedances and two isolation resistors. By changing the characteristic impedance of the transmission lines, the power division ratio can be adjusted. Meanwhile, good match and reasonable isolation performance can be obtained simultaneously. The proposed approach has been verified experimentally by using a 20-unit road side unit (RSU) antenna array operating at 5.815 GHz frequency range for a electronic toll collection (ETC) system. The proposed feeding network can be simply implemented on a single-layer substrate.