A Differentially Driven Dual-Polarized Dual-Wideband Complementary Antenna for 2G/3G/LTE Applications

A novel differentially driven dual-polarized dual-wideband complementary patch antenna with high isolation is proposed for 2G/3G/LTE applications. In order to generate dual-polarization and dual-wideband properties, a pair of biorthogonal dual-layer η-shaped tapered line feeding structures is utilized to feed two pairs of dual-layer U-shaped patches, respectively. The upper-layer U-shaped patches mainly serve the upper frequency band, while the lower-layer ones chiefly work for the lower frequency band. Besides, a horned reflector is introduced to improve radiation patterns and provide stable gain. The prototype antenna can achieve a bandwidth of 25.7% (0.78 GHz–1.01 GHz) with a stable gain of 7.8±0.7 dBi for the lower band, and a bandwidth of 45.7% (1.69 GHz–2.69 GHz) with a gain of 9.5±1.1 dBi for the upper band. Input isolation exceeding 30 dB has been obtained in the wide bandwidth. Thus, it can be potentially used as a base station antenna for 2G/3G/LTE networks

Impedance matrix of a folded dipole pair under eleven configuration

A new decade wideband antenna, the Eleven antenna, has been developed during the last years. The basic configuration of Eleven antenna is two parallel dipoles separated by half wavelength above the ground plane, which is referred to as the eleven configuration. In order to cascade the dipoles in log-periodic array for obtaining wideband performance, folded dipoles are often used. The input impedance of shorted folded dipole in free space has been analysed by using two-mode method: a transmission line mode and an antenna mode. In the present study, the impedance matrix of a pair of folded dipoles as a two-port network under the eleven configuration will be analysed by including the mutual coupling among elements of folded dipoles into the two-mode method. As veri. cation, an Eleven antenna with one pair of folded dipoles has been analysed by the present method, modelled in a commercial software - CST MS and manufactured. The results by using the present method agree well with the measured and simulated one

Wideband Circularly Polarized Reflectarray Antenna Using Rotational Symmetrical Crossed Dipoles

© 2023 IEEE. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1109/TAP.2023.3247943A wideband circularly polarized (CP) reflectarray (RA) antenna using rotational symmetrical crossed dipoles is presented. This is the first time investigating coupled crossed dipoles as the unit cell for wideband reflection bandwidth in the CP RA design. Equivalent circuit analysis shows that when a CP wave impinges on the designed unit cell, two series resonances, and two parallel resonances are simultaneously excited on the crossed dipoles. Owing to these four different resonances, the CP reflection bandwidth is greatly improved and elaborately adjusted by controlling the coupling between the crossed dipoles. The CP reflection bandwidth ratio of the unit cell is enhanced up to 2:1 for $S_{x} < -15$ dB with a thin thickness of $0.12 \lambda {0}$. Based on this unit cell, a wideband -20° collimated CP RA antenna with a circular aperture of 316 unit cells was designed, fabricated, and measured for final performance verification. The measured results show that a wide CP bandwidth of 7.6-15.9 GHz is achieved with the axial ratio (AR) < 3 dB. In addition, the measured 3 dB gain bandwidth is better than 43.7% with a peak realized gain of 26.3 dBic and maximum aperture efficiency (AE) of 58.3%.Peer reviewe

A Simple Low-Profile Coaxially-Fed Magneto-Electric Dipole Antenna Without Slot-Cavity

A simple coaxially-fed magneto-electric dipole (ME dipole) antenna is designed and experimentally evaluated. The proposed antenna does not require the conventional quarter-wavelength slot cavity for generating the magnetic dipole mode, and only consists of two simple rectangular horizontal patches, a vertical semi-rigid coaxial cable and a square ground plane. It makes the fabrication easier and can reduce the production cost. Also, as the quarter-wavelength slot cavity is removed in the proposed design, the thickness of the antenna can be reduced to 21 mm, i.e., 16.4% of the free space wavelength at the center frequency. The low-profile antenna shows comparable wide impedance bandwidth of 41.03% (S11 ≤ −10 dB), and a more stable and higher realized gain from 7.90 - 9.74 dBi (± 0.92 dB variation) over the operating frequency band from 1.86 GHz to 2.82 GHz (centered at 2.34 GHz). The maximum gain has increased around 9.4% when compare with that of the highest reported. While the gain variation in the passband of the proposed antenna is about 58% lower than that of those ME dipole antennas reported in the literature. The radiation mechanism and the effects of the critical parameters of the antenna are also explained with the assistance of the parametric study presented

A Compact Dual-Polarized Filtering Antenna with Steep Cut-Off for Base-Station Applications

© 2022 IEEE - All rights reserved. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1109/TAP.2022.3161280 ​​​​​​​A dual-polarized filtering antenna with steep cut-off and compact size is developed for base station applications. In this design, four controllable radiation nulls are obtained by utilizing split rings, slotted T-shaped branches, a single-stub tuner, and a parasitic loop. Split rings are firstly used as the dipole arms to obtain the 1st radiation null at upper out-of-band. Four T-shaped branches working as DGS are printed under the crossed dipoles to achieve the 2nd radiation null. The connected outer conductors of the differential feed structure acting as a single-stub tuner can provide the 3rd radiation null to further enhance the upper-band rejection. Finally, a parasitic loop is incorporated around the split rings, and the out-of-band rejection of the lower-band is further enhanced by the 4th radiation null. More importantly, the impedance bandwidth of the antenna can be expended with two newly introduced resonant modes. As a result, a compact filtering antenna with a wide operational bandwidth of 1.7- 3.01 GHz (56%) is realized for |Sdd11| < -15 dB with the isolation higher than 38 dB. The out-of-band suppression is higher than 18.4 dB in 3.1-4.5 GHz and more than 47 dB in 0.8-1.1 GHz.Peer reviewedFinal Accepted Versio

Configuration requirements for log-periodic array antennas

Log-periodic array antennas can provide a constant radiation performance and good reflection coefficient performance over a wide frequency band, which can be considered as an important characteristics of this type antennas. In this paper, the configuration requirement for general log-periodic array antennas is presented in order to have constant radiation function and periodicity of the reflection coefficient. Therefore, a guide rule for designing a wideband log-periodic array is obtained and a more efficient numerical simulation method can be applied for purely log-periodic array antennas