Analysis and design of circularly polarized traveling wave printed line antennas

The development and design of circularly polarized microstrip line antennas which have broader input impedance bandwidths than patch antennas are presented. The configuration is based upon a traveling-wave microstrip line antenna. The radiation mechanism of this type of structure arises from the discontinuities along the line. Radiation occurs due to the imbalance of oppositely imposed magnetic currents along the edges of the line discontinuities. The antenna demonstrated a radiation efficiency dependent upon the height above the ground plane. The broadside circularly polarized radiation pattern was obtained by geometrically shaping the microstrip line. This structure is a suitable element for phased-array antennas when a slot-coupled feeding mechanism is utilized.<>