Multi-band smart patch antenna for GPS/PCS hand-held units

A single-layer multi-probe-feeds patch antenna is proposed to feature a broad impedance bandwidth and low cross-polarization levels. Detailed investigations are presented through the results obtained using the method of moments technique. The proposed antenna has proved to have many attractive features so that it is recommended to be used in different telecommunication services in areas such as mobile satellite, terrestrial cellular, and personal communication systems. The design of the antenna considers simplicity, compact size, and low cost. It has approximately omnidirectional radiation pattern in the horizontal plane, achieving constant and reasonable gain. The impedance bandwidth reaches up to the order of 35%. A smart switching system used to change the feed points can raise the bandwidth to 55% of the center frequency. Stable radiation patterns are observed across the pass-band. The antenna has low cross polarization level where the antenna is elliptically polarized with axial ratio (the ratio of minor to major axis of polarization ellipse) is not exceeding 0.707 or -3 dB.