Wideband Magnetoelectric Dipole Antennas With Dual Polarization and Circular Polarization

Abstract

A new AE45 dual-polarized magnetoelectric dipole antenna is proposed. The antenna is excited by two À-shaped probes placed at a convenient location. The measured overlapped impedance bandwidth is 48% with standing-wave ratio (SWR) 1.5 from 1.69 to 2.76 GHz. The measured gains vary from 7.6 to 9.3 dBi and from 7.6 to 9.4 dBi for port 1 and port 2, respectively. The isolation between the two ports is larger than 30 dB. The proposed antenna achieves a low cross-polarization level of less than À21 dB and a low back radiation level of less than À29 dB over the operating frequency range. With a broadband 90 phase shifter and a power divider, the proposed antenna can radiate circularly-polarized (CP) wave and exhibit a wide impedance bandwidth (SWR 2) of 90% from 1.23 to 3.23 GHz, which covers the whole 3-dB axial-ratio (AR) bandwidth of 82% from 1.28 to 3.05 GHz. In this operation frequency band, the proposed CP antenna has a broadside gain of larger than 5 dBi above 1.45 GHz. Considering the common overlapped bandwidth limited by the impedance, AR, and gain, the proposed antenna exhibits an effective bandwidth of 71%.

A Broadband Dual-Polarized Magneto-Electric Dipole Antenna for 2g/3g/Lte/Wimax Applications

“…The coupling strip is stair-shaped which can be thought as the combination of two L-shaped strips with different lengths. Indeed, the stair-shaped feeding strip achieves more degree of freedom for impedance tuning than other feeding structure [9][10][11][12][13][14][15][16][17][18][19]. Its horizontal part is responsible for coupling electrical energy to antenna.…”

“…Moreover, its gain and beamwidth are not noticeably changed within its bandwidth. As a basic element, the magneto-electric dipole antenna was employed in a dual-polarization antenna [15][16][17][18][19]. In [17], The antenna achieved 65.9% impedance bandwidth (SWR ≤ 2) and stable radiation pattern with 3-dB beamwidth 61.5 • ± 3.5 • at H-plane and 62.5 • ±2.5 • at V -plane.…”

“…A novel differentially-driven dual-polarized magneto-electric dipole antenna was proposed [18] in 2013, which achieved a wide impedance bandwidth of 68% (0.95 GHz to 1.92 GHz) for SWR ≤ 2 and unidirectional radiation pattern with 3-dB beamwidth of 62% (1.09 to 2.08 GHz). In 2015, a new ±45 • dual-polarized magneto-electric dipole antenna with Γ-shaped feeding structure was presented [19]. The antenna exhibits good performance over the whole working bands, but its impedance bandwidth is not broad enough to support WiMAX applications at 3.5 GHz.…”

Broadband, Wide Beam Circularly Polarized Antenna With a Novel Matching Structure for Satellite Communications

“…A broadband, equalsplit power divider with 90 • phase difference is needed for the realization of circularly polarization. The broadband power divider we used in this paper is based on the feeding network in [9]. For the completeness and a better understanding of the paper, the feeding network used for the proposed antenna is introduced briefly.…”

Design of Circularly Polarized Planar Magneto-Electric Dipole Antenna

“…Despite the antenna has shown excellent performance with a staircase-shaped structure [3][4][5][6], where additional need of balun may be removed and antenna can provide dual-band with wide impedance bandwidth and high gain, with differential feeding structure [7,8], where the originally single ended operation is converted into differential ended to provide ultra-wide band, theoretically infinite differential port to port isolation and to be directly connected to differential microwave circuits, and with dielectric material [8][9][10], where magneto-electric dipole antenna is printed on dielectric material, it suffers from disadvantages of being bulky and pertaining complex structures. In [11][12][13], circular polarization has been achieved with 3-dB axial ratio bandwidth of 42.9%, 61.5% and 82% respectively, but the magneto-electric dipole antenna structure is non-planar. To the best knowledge of the authors, no true planar magneto-electric dipole antenna with circular polarization has been designed or presented.…”