Dexin Qu

Broadband C-Shaped Circularly Polarized Monopole Antenna

A novel broadband monopole antenna with circular polarization (CP) is designed and fabricated. It consists of a C-shaped monopole, an open-loop on the backside of the monopole and a modified ground plane. By placing a rectangular open-loop coplanar with the ground plane and connecting a rectangular vertical stub to the ground plane, wide impedance bandwidth is achieved, and axial-ratio (AR) bandwidth of the antenna could be improved simultaneously. The measured results exhibit a 65.2% (4.14 GHz, 4.28-8.42 GHz) CP bandwidth, and the 10-dB impedance bandwidth is 87.7% (6.66 GHz, 4.26-10.92 GHz). Finally, by placing a reflector underneath the antenna with its structural dimensions unchanged, one can obtain unidirectional radiation patterns with greatly improved gains. The advantages of the proposed antenna are the simple structure, a compact size, and a broad 3-dB AR bandwidth.

Compact Broadband Circularly Polarized Antenna With Parasitic Patches

A broadband circularly polarized (CP) antenna with compact size is proposed. The antenna is composed of a loop feeding structure which provides sequential phase, four driven patches, and four parasitic patches. The driven patches, which are capacitively coupled by the feeding loop, generate one CP mode due to the sequentially rotated structure and four parasitic patches are introduced to produce additional CP mode. By combining with the CP mode of the feeding loop, the axial ratio (AR) bandwidth is greatly broadened. An antenna prototype is fabricated to validate the simulated results. Experimental results show that the antenna achieves a broad impedance bandwidth of 19.5% from 5.13 to 6.24 GHz and a 3-dB AR bandwidth of 12.9% (5.38–6.12 GHz). In addition, the proposed antenna also has a flat gain within the operating frequency band and a compact size of

A NOVEL LOOP-LIKE MONOPOLE ANTENNA WITH DUAL-BAND CIRCULAR POLARIZATION

0.92\lambda _{0}\times 0.92\lambda _{0}\times 0.028\lambda _{0}

Broadband CPW-fed Circularly Polarized Falcate-shaped Monopole Antenna for UWB Applications

at 5.5 GHz.

CPW-fed C-shaped slot antenna for broadband circularly polarized radiation

A novel loop-like monopole antenna with dual-band circular polarization (CP) for the reception of WiMAX and WLAN is designed and implemented in this paper. The antenna consists of a radiating patch which is composed of an annular-ring linked by a square ring over the corner and a ground plane with embedded rectangular slit. The broad impedance bandwidth is achieved based on a novel monopole structure which is the combination of two perturbed loops and the perturbation causes the generation of right-hand circular polarization (RHCP) at 3.52GHz and left-hand circular polarization (LHCP) at 5.75GHz. In addition, by embedding a rectangular slit on the ground, the impedance bandwidth can be greatly enhanced. The measured results show that the proposed monopole antenna has an impedance bandwidth of 3.65GHz from 2.65 to 6.3GHz, reaching the particularly broad bandwidth of 81.6%. Furthermore, the measured 3- dB axial ratio (AR) bandwidths are about 440MHz at the lower band (3.52GHz) and 220MHz at the upper band (5.75GHz). The radiation characteristics of the implemented antenna are also presented.

Gain-Improved Broadband Circularly Polarized Antenna Array With Parasitic Patches

Abstract In this paper, a novel broadband CPW-fed circularly polarized (CP) monopole antenna is presented. The antenna is composed of a falcate-shaped patch and an improved ground plane. By adding an I-shaped stub in the ground plane, the impedance and axial-ratio (AR) bandwidths can be greatly enhanced. The antenna has been fabricated and measured. Good agreement is achieved between the simulation and measurement, which shows that the proposed antenna covers a 10-dB impedance bandwidth of 122% from 2.78 to 11.46 GHz, and a 3-dB AR bandwidth of 53.3% from 4.4 to 7.6 GHz.