A STUDY OF THE EFFECTS OF SYMMETRIC AND ASYMMETRIC DESIGN FOR CRLH-TL UNIT CELL ON XPD AND ISOLATION FOR DUAL LINEAR POLARIZED ANTENNA AT DIFFERENT VALUES OF PHASE SHIFTS

摘要

Dual linear polarization antennas with low cross polarization have been widely used for synthetic aperture radar andwireless communication applications. This work presents a new design of a dual linear polarization single microstrip patch antennawith low cross-polarization pattern and high isolation between two input ports. The work has two main objectives. The first is togenerate different values of phase shifts (0o-90o) using composite right left transmission line (CRLH-TL) metamaterial (symmetricand asymmetric configurations), in order to investigate the cross-polarization discrimination (XPD) and isolation between the twoinput ports for a dual linear polarized antenna at the frequency of 10 GHz. The simulation reveals that the XPD of 34 dB andisolation of -30 dB at a phase shift of 40o. This method results in significant improvement in co-cross polarization discrimination atthe phase shift of 40o in comparison to the conventional antenna. The simulation, in this regard, reveals an improvement of 7 dB inprinciple planes (E and H). The second objective is a comparative study between the symmetric and asymmetric unit cells and theireffects on the cross polarization patterns. Furthermore, we report on the effect of phase shift on the other characteristics such asgain and bandwidth. The simulations are evaluated utilizing the commercial full-wave simulator Ansoft High-Frequency StructureSimulator (HFSS).