Wideband planar monopole antenna

A wideband planar monopole antenna is designed.The radiator of the proposed antenna is a rectangular copper sheet,whose bottom is beveled.The feeding point is offset from the center of the radiator.The use of beveling radiator and asymmetrical feeding enhances the impedance bandwidth significantly.The influences of the antenna's dimensions,beveled angle and feeding position on the performance of the antenna were analyzed using a commercial software package called Ansoft HFSS,and then the optimized parameters were presented.Finally,the prototype was manufactured according to the optimized parameters.Its measured operating bandwidth is 70~3000 MHz with voltage standing wave ratio(VSWR) lower than 3.5:1.The measured results of the VSWR and pattern agree well with the calculated results.