Design of Penta-Band Omnidirectional Slot Antenna With Slender Columnar Structure

In this paper, we have proposed a co-located and folded slots antenna for multiband applications. The proposed antenna consists of three radiating slots, arranged on a compact square columnar structure. By properly tuning the dimensions and the positions of the co-located slots, the proposed antenna operates in penta-band, including DCS, PCS, UMTS, 2.5-GHz, and 3.5-GHz WiMAX bands. Additionally, omnidirectional radiation patterns are provided in the azimuthal plane for all the operating bands. The overall volume of the proposed square columnar antenna is only 50 × 10 × 10 mm³, which is suited for volume-limited systems. A prototype of the proposed antenna is fabricated and tested, to validate the design idea. The measured data, including S parameter, radiation pattern, and gain, agree well with the simulation results.