OLR-filtenna for Wi-Fi applications

Microstrip open loop resonators with annular or square configuration are widely used in the design of filters and antennas. In this paper a new compact microstrip OLR based filters are designed and analyzed. This filter configuration is extended to work as a filter antenna. Proposed filtenna consists of a microstrip open loop resonator (OLR) based narrow band pass filter and antenna which operates at 2.45 GHz. Filtenna is designed on Fr4 substrate with OLR and microstrip patch on a plane and a uniform ground plane on other face of the substrate. The combination of OLR and microstrip gives a high Q band pass response and offers better coupling characteristics. The tuning of the antenna operating frequency is achieved by changing the operating band of the filter. The optimum performance is achieved when the antenna resonant frequency encompasses with the band pass frequency of the filter. The electrical property of the proposed structure is investigated analyzed and optimized numerically by using the method of moments in ANSYS High Frequency Structure Simulator (HFSS).