Low-Profile Dual-Band Tripolarized Antenna Using Monopolar Slotted Patch

A dual-band multiport antenna with three orthogonal polarizations is proposed for 2.45 and 5.8 GHz bands. It consists of a monopolar slotted patch with shorting vias for vertically polarized omnidirectional radiations and differential-fed stacked patches for x- and y-polarized broadside radiations. To avoid undesired effects among different radiation modes, four shorting vias in the monopolar patch are utilized to feed the stacked patches. The final design with 0.07 lambda(2.45-GHz) profile achieves measured 10 dB return loss bandwidths of 50 and 180 MHz at the two target bands, respectively, and an isolation of >= 40 dB among all the ports, showing significant improvement as compared to the existing designs for the same application in the literature. Its radiation characteristics are validated by the far-field measurements, which illustrate highly symmetrical patterns and low cross polarization in all the operation modes.