AbstractA rectangular microstrip patch antenna is electromagnetically excited by microstrip line, but fed from the short side. The effect on the radiation pattern of variation of the feedline inset/off set position is studied experimentally. It is observed that the radiation pattern has two distinct lobes with variable, asymmetric amplitudes. The angle between the two lobes is found to be about 95° ± 10°. But the lobe amplitudes show a periodic variation with normalized inset for each offset value. © 1994 John Wiley&Sons,