Multi-band equilateral triangular microstrip antennas

The multi-band microstrip antennas are realized by placing open circuit quarter wavelength stub on the edges of the patch or by cutting nearly half wavelength or quarter wavelength resonant slot inside or on the edges of the patch. The stub offers either capacitive or inductive impedance around the resonance frequency of the patch and realizes the dual frequencies. The slot adds another resonant mode near the patch resonance and realizes dual frequencies. In this paper multi-band equilateral triangular microstrip antennas by placing the quarter wavelength stub on the edges of the patch or by cutting the resonant U-slot or pair of rectangular slots inside the patch or by using the combinations of the stub and the slot, are proposed.