Rectangular microstrip antennas with stub along the non-radiating edge for dual band operation

A rectangular microstrip antenna with a half wavelength short circuited stub placed along the radiating edge exhibits dual frequency operation. Dual frequency operation is obtained with quarter wavelength open circuited stubs also. Two unequal stubs of nearly /spl lambda//4 length placed along both the radiating edges yield triple frequency operation. This paper describes the effect of a /spl lambda//4 open ended stub placed along the nonradiating edge of the square or rectangular patches for dual frequency operation. These antennas have been analyzed based on the multiport network model using a segmentation method with the Green´s functions approach.