Multiobjective Optimization Design of Compact Filtering Patch Antenna With Generalized Filtering Slot

This article proposes a novel technique for designing microstrip filtering patch antenna by etching the generalized filtering slot (GFS) on the patch. Surface current-controlled in-band multiple resonances and radiation nulls in both sidebands can be achieved relying only on the configuration of GFS without any parasitic or stacked structures outside of the radiation patch, which ensures the compact size and low profile. The GFS with two-part structure can be effectively characterized by the distributed contour nodes with distance parameters and L-shaped slot lines with controllable turning points, whose geometry is completely encoded by a binary design matrix. The compact patch antenna with wideband, high selectivity and high suppression level can be acquired by implementing multiobjective optimization search for the optimal nodes distribution including feed points, along with the optimal distance parameters and slot width for slot construction. For demonstration, a filtering antenna with square patch working at 3.5 GHz is designed and fabricated, showing a realized gain of 5.8 dBi, impedance bandwidth of 12.0%, and suppression over 20 dB with steep roll-off.