171 / 2015-11-24 14:29:13

Design and Simulation of Roof Mounted UHF Antenna for Auto motives

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A low-profile, electrically small antenna with omnidirectional vertically polarized radiation similar to a short mono pole antenna is presented. The antenna features less than λ/32 dimension in height and λ/8 in lateral dimension. It can also be employed with a ground plane (roof surface/rooftop). The geometry of the antenna is derived from a quarter-wave transmission line resonator fed at appropriate location to maximize current through short-circuited end. The lateral dimension of the antenna is miniaturized superposition of additional resonator placed in a parallel arrangement. The meandering between the short-circuited end and the feed point also facilitates the impedance matching and matched to 50 ῼ coaxial line without the need for external matching. The antenna is design and simulated by CST Microwave Studio Program. The effect of the antenna parameters on the bandwidth will be investigated. It is easily embedded on the roof of the vehicle. Moreover, the proposed antenna has simple structure, low profile, easy mounting and relatively good bandwidth.It is also shown that this antenna features excellent impedance match and nearly omnidirectional radiation pattern in horizontal plane over a majority fraction of bandwidth.