U-Shaped Slots Loaded Patch Antenna With Defected Ground Plane For Multiband Modern Communication Systems

In this article, the design and performance of circular radiating patch element with two U-shaped slots and defected ground plane, comprising of a triangular notch monopole structure with rhomboid shape resonator, is reported. The proposed multiband antenna has a compact structure design for GSM 1800 MHz, WLAN, WiMAX and UWB communication systems. The antenna is designed on FR4 glass epoxy substrate of size 39 mm x 34 mm x 1.59 mm by using computer simulation tool CST Microwave Studio 2014. For confirmation of simulation results, prototypes are fabricated and their performance is tested in free space. Measured results demonstrate that fabricated antenna provides triple bands with impedance bandwidth of 157 MHz (1.733 GHz to 1.89 GHz), 3.2 GHz (2.29 GHz to 5.49 GHz) & 10.45 GHz (6.83 GHz to 17.28 GHz), almost flat high gain between 4 to 6 dBi and good radiation patterns in the desired frequency range. The maximum measured gain of proposed structure is close to 6.59 dBi at 4.40 GHz. The circular polarization is also realized in the frequency range 4.12 GHz to 5.20 GHz with axial impedance bandwidth 1.08 GHz. The specific absorption rate SAR values of proposed design are also evaluated at various frequency spots which are well within the SAR values specified by the FCC. Proposed design may be proved a useful structure for advance radio communications systems as well as for the present requirements in defence applications.