A Wideband Water Patch Antenna with Polarization Diversity

In this letter, a wideband water patch antenna with polarization diversity is proposed. Simultaneously, different polarization states are realized by changing the operation modes between TM11 and TM02 modes of a circular water patch and switching the feeding ports. To obtain an overlapped frequency band between these two modes, a size-changeable water patch is used. An adjustable plexiglass container is used to contain water and change the size of the water patch, while a disk-loaded probe and two pairs of L-probes are applied as the switchable feeding ports and also support wide bands. A fully functional prototype was fabricated and tested to verify the proposed design. The measured results show that all three polarization states can work well with a high isolation level. The overlapped −10 dB impedance bandwidth of three polarizations is 23.40% (2.34 GHz∼2.95 GHz). With the advantages of multipolarization states, ease of fabrication, and high optical transparency, the proposed antenna is suitable for various applications, such as indoor communications.