Studying microstrip patch antennas using the theory of characteristic modes

The theory of characteristic modes (CMs) has become an increasingly popular and attractive subject for many researchers due to its rising reliability, fast and simple computation, and appealing properties. Numerous amount of research work has been mainly done on antennas made of conducting materials. Unlike the theory application on conducting antennas, there have been fewer publications and quantitative results on antennas made of penetrable or composite materials. And for the first time, an attempt is made in this present work to study and examine both the modified and substructure CMs of microstrip patch antennas (MPAs) owing to their popularity.