Circularly-Polarized Differential Antenna Array Fed by Single-Ended-to-Balanced Power Dividers with High Common-Mode Rejection

This paper presents a differential feeding network comprising of a new type of single-ended-to-balanced power dividers with high level of common-mode rejection. The single-ended-to-balanced power dividers are built based on slotline-to-microstrip transitions, which are able to provide high commonmode suppression and low differential-mode-to-common-mode conversion levels. A wideband differential circularly-polarized (CP) antenna array is designed fabricated and tested using the differential feeding network. The experimental results verify that the presented differential feeding network can be used in feeding differential CP arrays to achieve high gain, symmetrical patterns and a wide axial ratio bandwidth.