A wideband circularly polarized antenna using mutual coupling method

Abstract

A novel wideband circularly polarized (CP) antenna is presented in this article. The proposed antenna consists of a four-leaf clover patch, four L-probes, and wideband networks. Based on the tightly coupled mechanism, the four L-probes are formed as a ring with the adjacent ones kept close for strong mutual coupling. Consequently, the proposed antenna realizes a wideband impedance matching. Meanwhile, the fourleaf clover patch is put closely inside of the ring for further improving the impedance bandwidth, which is proximity-coupled fed by the four sequential-rotation L-probes with phase of 08, 908, 1808, and 2708. The four L-probes are connected to the respective ports of a wideband feeding network by a two-stage impedance transforming network. The measured results indicate that the proposed design has an impedance bandwidth of 66.7% from 1.0 to 2.0 GHz for VSWR 2 and a 3-dB axial ratio bandwidth of 56.5% from 1.08 to 1.93 GHz. Furthermore, in the operating bandwidth, stable and symmetry radiation patterns and high gain are obtained. The design has a 3-dB gain bandwidth of 38% from 1.3 to 1.9 GHz with a peak gain of 8.5 dBic.

Mutual Coupling-Based Compact Wideband Circularly Polarized Antenna

“…The FN is placed over this substrate. From a practical perspective, it is very important to shield the structure from the surface on which it has to be mounted, an issue which was not considered in many previous works [15,17,19,20,21]. In order to shield the antenna, the last layer is fully metallic.…”

“…Although a 96.3% bandwidth has been achieved in [15], the four hexagonal patches occupy a 1.13λ0×1.13λ0 area. Significant size reductions were reported where the patches are replaced by four dipoles [19], or just one four-port radiator [20,21,22,23]. For example, the SR technique was recently used for an annulus patch that is fed by four proximity coupled strips [22].…”

Symmetrical double-comb multi-slotted large bandwidth antenna for intelligent transportation systems

“…The miniaturized planar‐inverted wide BW antennas have been used to obtain smaller size and lower losses in automobile safety and tracking systems . A single transmitter with two receivers has been used for ITS automotive applications . The design of an omnidirectional broadband planar antenna has been used for vehicular telemetry applications .…”

Low profile coupling feed circularly polarized antennas for WLAN applications

“…The most common method of achieving circular polarization is by truncating the corners of square patch or by making asymmetrical cross slot in the middle of the patch. The other method includes insertion of slits, spur lines, and loading of stubs . Few other designs include loaded patch with asymmetric U‐slot, asymmetric L‐slot embedded patch, radiating patch integrated with chip resistor, using complementary split‐ring resonator and defected ground structure .…”

“…The other method includes insertion of slits, spur lines, and loading of stubs. [1][2][3][4] Few other designs include loaded patch with asymmetric U-slot, 5 asymmetric L-slot embedded patch, 6 radiating patch integrated with chip resistor, 7 using complementary split-ring resonator 8 and defected ground structure. 9 Many other antenna designs using microstrip line feed for exciting the radiator are also reported in the last few years.…”