Bandwidth Enhancement of Monopole UWB Antenna With New Slots and EBG Structures

Two methods in terms of bandwidth broadening are proposed and compared for monopole slot ultrawideband (UWB) antennas supporting mobile terminal applications. The original antenna has a bandwidth of 9.27 GHz (1.73-11 GHz) that covers PCS1900, UMTS2000, TD-SCDMA, WLAN 802.11b/g or Bluetooth, LTE, WiMAX, and UWB frequency range. In this letter, by cutting two new slots on the ground plane, the antenna can expand its bandwidth to 9.33 GHz (1.67-11 GHz) that is available at extra DVB-H, DCS1800 services. Meanwhile, the bandwidth of the antenna with conventional mushroom-type electromagnetic band-gap (CMT-EBG) embedded on both sides of a 50- Ω microstrip line can be enhanced to 9.47 GHz (1.53-11 GHz) with the extra GPS covered. The largest impedance bandwidth of 151% can be obtained. Moreover, the comparisons of gain characters as well as the radiation patterns are discussed at the bands of interest. It is illustrated that the gain of the antenna based on CMT-EBG is higher than other two cases except to the range of 5.19-5.93 GHz and the radiation patterns are basically identical. The antennas are fabricated on FR4 substrate, and the deviations between measured results and simulated results are discussed.