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
$\lambda _{2.45-\text{GHz}}$
profile achieves measured 10 dB return loss bandwidths of 50 and 180 MHz at the two target bands, respectively, and an isolation of
$\ge$
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.