DESIGN AND TESTING OF A DUAL BAND SIW ANTENNA LOADED WITH CRLH TL UNIT CELL FOR WIMAX APPLICATION

Abstract

In this report, a CRLH-TL Unit Cell Loaded Dual-Band SIW Antenna for WiMAX applications is proposed. The antenna has a radiating patch composed of composite right/left hand transmission line (CRLH-TL) unit cells which are excited by two λg/4 resonators with a shorted pin, for impedance matching, in between to supress the harmonics. The proposed antenna resonates at dual band having frequencies at 3.65 and 4.2 GHz. The measured reflection coefficient is less than -10 dB. The radiation efficiency over the band are 71 and 60 % and gain obtained are 2.7 and 5.8 dBi, respectively. Though there is wide application of CRLH, which have been discussed in the coming chapters, yet they have drawbacks regarding gain and efficiency. The simulations are done by one full wave packages i.e. ANSYS HFSS that associated with finite element method (FEM). The simulated and measured results have been found good agreements with each other. Second part of this report is an extended portion of the work done in above part. Basically, Substrate Integrated Waveguide (SIW) technology has been used in the same design of proposed antenna with minor changes in dimensions with improved performance in terms of peak realized gain, radiation efficiency, FTBR, reduced cross-polarization level for WiMAX-applications has been proposed in this proposed work. Same CRLH patch with its mirror image on the opposite side has been used in differential and common mode. The measured results show that the SIW based improvised antenna have reflection coefficient less than -10 dB. The simulated maximum gains are 3.2 and 7.1 dBi, respectively. The antenna has achieved a simulated radiation efficiency of 55 and 87 %at two different frequencies. The simulation and measured results are matched and are much higher compared to values reported in the literature for CRLH based antennas.