In this letter, an substrate integrated waveguide ‐based self‐quadplexing antenna based on a modified Jerusalem cross‐shaped slot is presented. By introducing different lengths of the slots of Jerusalem cross, the antenna operates at four different closely spaced resonant frequencies 4.08, 4.37, 4.61, and 4.97 GHz. The proposed quadplexer antenna achieved a minimum port isolation of
20 dB...