Dual-band microstrip rectangular patch antenna using a spur-line filter technique

Over the past years several attempts have been made concerning dual frequency operated microstrip patch antennas where an increase in length or height of the patch is generally expected. This paper presents a novel structure to accomplish dual frequency operation by using a spur-line band-stop filter within the width of the radiating edge of the patch opposite the feed point. This dual frequency operation can be obtained without increasing either the size or the thickness; however, through experimental results, the characteristics in both frequencies are shown to be nearly identical.