A Simple Polarization-Reconfigurable Series-Fed Patch Array Using Switchable Feeding Network

This paper presents a polarization-reconfigurable series-fed patch antenna (SFPA) with high gain and a simple switching mechanism. The proposed design comprises of four slotted circular patches arranged in a 1 × 4 configuration. For excitation, the array is capacitive fed by a single T-junction power divider. By controlling the bias state of three PIN diodes on the divider, the antenna's polarization can be switched among a single linear and dual-sense circular polarization. To validate the design concept, an array prototype is fabricated and measured at the operating frequency of 5.0 GHz. The measurements result in a common operating bandwidth for all radiating modes of about 1.8%, ranging from 4.95 to 5.04 GHz. Besides, a stable broadside gain of around 12 dBi is also obtained.