U-slot patch antennas for dual-band or multi-band applications

A wide band patch antenna fed by an L-probe can be designed for dual- and multi-band applications by cutting U-slots on the patch. The half wavelength long U-slot resonates and introduces a band-notch. Multiple band-notches could be introduced by cutting several U-slots on the patch. Simulation and measurement results are presented to illustrate this design. Stable broadside radiation patterns are maintained across the bands.