Frequency Tuning Range Enhancement of a Filtering Patch Antenna

A recently proposed low-profile frequency-reconfigurable filtering patch antenna is further optimized to achieve a wider frequency tuning range. The design realizes the filtering functionality using four parasitic strips and two lateral stubs. To achieve frequency-reconfigurability, sets of varactor diodes are integrated on the main patch, parasitic strips, and lateral stubs to vary their electrical length. The extension proposed here for the original design integrates thin copper extension lines with the varactor diodes. These lines bridge the parasitic strips, lateral stubs, and the main patch with their respective tuning elements, which reduces the parasitic parallel capacitance to the varactor diodes. As a result, the proposed evolved design shows a 31.5% frequency tuning range, which is 9.6% wider compared to the original design.