Planar Two-Arm Spiral Antenna Fed by Microstrip Line

摘要

A planar microstrip-fed two-arm spiral antenna has been designed for achieving wideband circularly polarized bandwidth in this paper. Compared with conventional spiral antennas, a simple feeding line is employed to feed the antenna. The planar structure can be printed using a single layer substrate without an external balun. In addition, the arc-shaped cut is embedded in the ground plane and a tapered impedance transformer is utilized to improve the impedance matching across a wide frequency band. The obtained results confirm that the proposed antenna can achieve a circularly polarized bandwidth from 2 to 4 GHz with the peak realized gain varying from 2 to 3.7 dBi.