Planar tri-band antenna element in L/S/C-bands

A planar tri-band rectangle-rings microstrip antenna design is presented in this paper. The antenna has three equally tuned resonant bands and also maintains consistent radiation patterns in all the operational sub-bands. The antenna has a single port and its cavity-backed waveguide-like configuration results in minimum mutual coupling levels in antenna array configuration. The antenna element is tuned to operate over the L/S/C radar bands. The antenna is simple and compact structure and measures only 0.25lambda × 0.25lambda at the lowest frequency of operation. Due to its small dimensions, the element is well-suited for application to dense wide-scan phased arrays.