A Loop Antenna with Parallel Wires for Circular Polarization—Its Application to Two Types of Microstrip-Line Antennas

We propose a novel loop antenna having parallel wires. The antenna is analyzed using the method of moments. It is found that when the distance between the parallel wires is appropriately chosen, the antenna radiates a circularly polarized (CP) wave. The rotational sense of the CP radiation depends on the feed location at the junction of the loop and parallel wires. On the basis of these radiation characteristics, we design two types of loop-line antennas whose radiation mechanisms are different from each other.