Study on Broadband Sleeve Antenna with Plate Element and Parasitic Element

A conventional sleeve antenna is composed of a coaxial cable, an inner conductor and a choke structure. The choke structure suppresses a leakage current flows on the outer conductor of the coaxial cable. In this paper, the planar sleeve antenna with flat element is proposed. The relative bandwidth (VSWR $\leq$ 3) of the proposed antenna is 125.9% (from 810 MHz to 3560 MHz) in simulation. The proposed antenna works in broadband and has simple structure.