A dual-band planar inverted-F patch antenna with a branch-line slit

By embedding a branch-line slit in the radiating patch of a planar inverted-F patch antenna, novel 900 and 1800 MHz dual-band operation is obtained. The embedded branch-line slit has two branch slits (one long folded slit and one short bent slit) protruding from the main slit which has an open end at the patch boundary. The main slit and the long folded branch slit together strongly meander tire excited patch surface currents starting from the feed to the portion of the patch encircled by the folded branch slit, which leads to a significant reduction in the required dimensions for the proposed antenna. In addition, the two operating frequencies have wavelengths corresponding to about 4.0 and 2.0 times the length of the above-mentioned meandered patch surface current path. The short bent branch slit, on the other hand, mainly serves as a tuning slit for achieving good impedance matching of the two operating frequencies. Tire proposed antenna and experimental results are described in detail in this paper. (C) 2002 John Wiley Sons, Inc.