Dual-band Dual-polarized Antenna Array Research Articles

Compact Shared-Aperture Dual-Band Dual-Polarized Array Using Filtering Slot Antenna and Dual-Function Metasurface

This article presents a shared-aperture dual-band dual-polarized antenna array for fifth-generation (5G) mobile communication. Within one radiating aperture, four higher band (HB) patch antenna elements are placed over the lower band (LB) full-wavelength slot antenna. The proposed array is miniaturized by bending the ground plane of the slot antenna. Suppression of cross-band mutual coupling and scattering is achieved by using the filtering performance of the slot antenna and a dual-function metasurface. The filtering performance of the slot antenna is realized using coupled microstrip lines inside the radiating slot and open-ended stubs on the feeding lines. The dual-function metasurface operates as an artificial magnetic conductor reflector in the LB and bandpass frequency-selective surface in the HB. By placing the dual-function metasurface behind the slot antenna, the radiation of the slot antenna is enhanced in the LB but not HB, and the negative effect of its HB scattering on the HB antennas is reduced. The working mechanism is explained in detail. The measured and simulated results demonstrate that the proposed array has stable radiation patterns in the bands of 0.69–0.96 and 3.4–3.7 GHz with a high cross-band isolation of over 32 dB and is more compact than the previous works.

Ferrite-Loaded Dual-Polarized Antenna for Decoupling of Multiband Multiarray Antennas

A dual-band dual-polarized antenna array is considered to analyze the operating mechanism of the resonant coupling in multiband multiarray antennas, firstly. The considered antenna is composed of a lower band (LB) antenna operating from 690 to 960 MHz and two columns of higher band (HB) subarrays operating from 1690 to 2690 MHz. Then, a novel method of suppressing the resonant coupling interference by using ferrite cores is proposed. It is implemented by loading ferrite cores on the feed cables of the HB elements. The resonant coupling interference is caused by the LB common-mode currents distributed on the HB feed cables. It will seriously distort the LB radiation patterns. With the ferrite cores, the LB common-mode currents are eliminated, and then, the distorted LB radiation patterns are completely restored. Furthermore, the loaded ferrite cores hardly affect the performance of the HB elements.

A Dual-Band Dual-Polarized Antenna Array Arrangement and Its Application for Base Station Antennas

This letter presents a dual-band, dual-polarized antenna array arrangement for low grating lobe base-station antenna applications. The presented array arrangement uses two different lower band elements to achieve a 2.5-time element spacing array scheme, in which lower band elements spacing is 2.5 times of upper band elements spacing. With this arrangement, both the lower and upper band element spacing can be reduced, leading to a better grating lobe performance. To verify the idea, an antenna array operating at two bands, namely, 690-960 and 1690-2690 MHz, is presented. For 690-960 MHz array, two different radiation elements are designed, each of them has two pairs of bent dipoles for dual-polarization operation. The smaller lower band element is embedded with one upper band element. Meanwhile, the larger one is embedded with two upper band elements. An array consisting of five lower band elements and 12 upper band elements is fabricated and tested. Measured results show that the array has a good performance with return loss larger than 15 dB, ports isolation better than 28 dB. Besides, the grating lobe value is better than -12 dB at tilt angle 12° for both upper and lower band, which is a significant improvement over its former counterparts.

Integration of 5G Rectangular MIMO Antenna Array and GSM Antenna for Dual-Band Base Station Applications

In this paper, a dual-band dual-polarized antenna array is presented for 5G base station application. The developed antenna array consists of a $4\times 4$ planar MIMO array operating at 3.3-5.0 GHz band (upper band UB) and a single antenna element working at 0.69-0.96 GHz band (lower band LB). The dual-band operation is based on our previously proposed antenna topology. The novelty of this paper is that the UB antenna array is a large-scale rectangular lattice array with 16 antenna elements for practical MIMO applications. Meanwhile, both the cross-band and in-band mutual coupling among the LB and UB antennas are furtherly suppressed by employing three decoupling techniques including rectangular ring resonator, ferrite chock ring, and novel baffle structure. With these decoupling technologies, the UB antenna array and the LB antenna are successfully integrated within a compact volume of $0.93\lambda _{L} \times 0.93\lambda _{L} \times 0.17\lambda _{L}$ ( $\lambda _{L}$ is the wavelength at 0.82 GHz). Experimental results show that the proposed dual-band antenna array offers high cross-band port isolation (>30 dB). Stable radiation patterns are also achieved for both the LB and UB antennas with averaged gain of 8.6 dBi and 7.3 dBi, respectively. The radiation efficiency is higher than 90% across the entire operation bands. It is the first time to realize a large scale sub-6 GHz MIMO antenna array shared-aperture working with a GSM band antenna element in a such compact volume.

Dual-Band Dual-Polarized Antenna Array With Flat-Top and Sharp Cutoff Radiation Patterns for 2G/3G/LTE Cellular Bands

This paper proposes a dual-band dual-polarized planar antenna array with flat-top and sharp cutoff radiation patterns for 2G/3G/LTE base stations. The array consists of $8 \times 8$ antenna elements arranged with nonuniform spacings and is assigned with optimized nonuniform excitations to achieve flat-top and sharp cutoff radiation patterns with low sidelobes. The radiating element consists of two square-shaped PCB boards. Extra adjustable coupling elements are introduced in the H-shaped patches to improve the impedance matching performance in an array environment as well as to reduce the size of the antenna element. In the 1.71–2.69 GHz band, the dual-polarized radiating element exhibits stable radiation patterns, excellent impedance matching (VSWR 40 dB). Frequency band selective variables are defined to group the antenna elements. They are optimized along with the element spacings and complex excitations in the optimizer to ensure stable flat-top radiation patterns. Rectangular-shaped baffles are introduced to reduce mutual couplings. A prototype of the $8 \times 8$ antenna array has been fabricated and measured. The results indicate that the proposed dual-band dual-polarized planar array achieves a half-power beamwidth of 50° ± 5° in both the H-plane and E-plane. The proposed antenna and its array exhibit attractive potentials for 2G/3G/LTE base station applications.

DUAL-BAND DUAL-POLARIZED ARRAY FOR WLAN APPLICATIONS

This paper presents a dual-band dual-polarized antenna array design for WLAN applications. Four double-dipole elements are orthogonally interleaved to facilitate operation in both the standard WLAN frequency bands (IEEE 802.11b and IEEE 802.11a) simultaneously. The two linear polarizations have separate ports. The presented design is characterized by dual-band operation, reasonably good front-to-back ratios, average gains of 5.2dBi and 6.2dBi over the 2.4 and 5.2GHz bands respectively, stable end-flre radiation patterns and very low cross-polarization levels.