A new compact and wideband CPW-fed sleeve antenna

Abstract

In this article, a sleeve antenna with a wide impedance bandwidth that consists of a coplanar waveguide line connected to a metallic cylinder is presented. The effect of design parameters on the impedance bandwidth is considered by some simulations. In addition to the wide impedance bandwidth, the omnidirectional pattern, high efficiency, low cost and easy fabrication process, and compact dimensions cause this antenna to be a good choice for some applications at low VHF/UHF frequency bands. Due to the flexible structure of this antenna, it is possible to cover the various frequency bands by changing the parameters of the antenna. In this work a typical model of the proposed antenna for the frequency range of 127 to 586 MHz is fabricated and compared with other previous works. An equivalent circuit model has been proposed to better understand how the antenna works. The proposed antenna has a bandwidth of about 128.7% for a voltage standing wave ratio (VSWR) of less than 3, compact size of 0.274λ × 0.047λ and higher than 90% efficiency.