Wide band confocal annular elliptic microstrip antenna

We demonstrate how to utilize the modes of a confocal annular elliptic patch to design a wide band antenna. The TM/sub 12/ mode of the confocal annular elliptic patch has been used previously to design wide band antennas. We put the reasons for this on a sounder analytical basis and then show how to combine the modes in such a manner as to extend the bandwidth even further.