Reduced Cross-Polarization Patch Antenna with Optimized Impedance Matching Using a Complimentary Split Ring Resonator and Slots as Defected Ground Structure

An innovative method is proposed to improve the cross-polarization performance and impedance matching of a microstrip antenna by integrating a complimentary split ring resonator and slots as a defected ground structure. An equivalent circuit model (ECM) enables the design take into consideration the mutual coupling between the antenna patch and the Defected Ground Structure. The input impedance and surface current density analysis confirms that the integration of a CSRR within a rectangular microstrip patch antenna leads to uniform comparative cross-polarization level below 40 dB in the H-plane, over an angular range of ± 50°. Introducing parallel slots, as well, leads to a reduction of spurious antenna radiation, thereby improving the impedance matching. Measurements conducted on a fabricated prototype are consistent with simulation results. The proposed antenna has a peak gain of 4.16 dB at 2.6 GHz resonating frequency, and hence is good candidate for broadband service applications.