Probe compensated single feed circularly polarized fractal-shaped microstrip antennas

Abstract

A single feed circularly polarized fractal boundary microstrip antenna with improved axial ratio bandwidth is presented. The low-axial ratio bandwidth of single feed circularly polarized microstrip antenna is due to its probe reactance. In this article, the inherent disadvantage of this low-AR bandwidth is overcome by compensating the probe reactance by incorporating capacitance in the form of small patch between the radiating patch and the probe. The perturbation of the patch is done using fractal curve as boundary. The proposed antenna exhibits impedance and axial ratio bandwidths of 9 and 2.2% respectively at 2.4 GHz.

A wideband circularly polarized antenna using mutual coupling method

“…Here, is the total number of ports, is the port numbering index, and is a complex number representing magnitude and phase for the source. From formulae 1 and , we know that the active VSWR of one port is achieved when the other three ports are also excited simultaneously. In this case, the matching behavior of one port is actually affected by the impedance mismatch of one port itself and the mutual coupling among the other three ports.…”

“…Generally, CP antennas can be categorized into single‐fed type and multi‐fed type according to their feeding methods. For the single‐fed type, many microstrip CP antennas have been proposed . It can be observed that all of them have narrow impedance and axial ratio (AR) bandwidths.…”

“…For the single-fed type, many microstrip CP antennas have been proposed. [1][2][3] It can be observed that all of them have narrow impedance and axial ratio (AR) bandwidths. Recently, the single-fed CP antennas using crossed dipole with curved-delay line are published with great achievements in the bandwidth enhancement.…”