A simple slot antenna for triple-polarization diversity application

A novel slot antenna with triple-polarization diversity is proposed in this paper. The proposed antenna consists of a circular slot that acts as a radiator, triple-microstrip line that acts as a feeding structure, a protruding stub, and slit applied to a GND. First, an antenna with dual-circular polarization (CP) characteristics is designed. The CP property is easily obtained using a protruding stub that acts as a perturbation in circular slots. The high isolation between two ports is achieved by the protruding stub and the slit applied to ground plane. From the measured results, the CP operating bandwidth is found to be 18.6%. The isolation is less than −14 dB within the operating bandwidth. Second, another feeding structure is implemented for linear polarization (LP). The measured CP bandwidth of the triple-polarization antenna is 12.7%, and isolation between ports is below −16.5 dB at the operating bandwidth.