Dual-band Dual-polarized Antenna Research Articles

A Dual-Band Dual-Polarized Base Station Antenna Array With Isolation Enhancement

A Dual-Band Dual-Polarized Base Station Antenna Array With Isolation Enhancement

Beam Shaping of Base Station Antenna Array by Using MMPTE

In this paper, a beam shaping scheme is presented for the optimal design of base station antenna array. The antenna array consists of four linearly arranged dual-band dual-polarized antenna elements, and it is designed to cover the LTE frequency band (2.3-2.69 GHz) and 5G frequency band (3.3-3.6 GHz). The shaped beams with possible maximum gain, suppressed sidelobe level smaller than -16 dB, front-to-back ratio larger than 18dB, and filled-up null point larger than -23 dB are accomplished through two steps by using the unconstrained methods of maximum power transmission efficiency (MMPET) and constrained MMPTE, respectively. In the proposed beam shaping scheme, all the realistic factors of the antenna array have been taken into account, such as the difference of element radiation patterns, complexity and tolerance of the element structure and spacing.

Dual-band Dual-polarized Dipole Antenna for Gain and Isolation Enhancements

A ± 45° linear-polarized cross-dipole with enhanced gain and isolation has been designed as an example for 5G applications in this paper. By adding stepped reflector and combined director, the isolation and radiation performance of the antenna can be improved significantly. According to the experimental results, the bandwidths with reflection coefficient lower than 10 dB in the low frequency band and high frequency band are 9.5% (3.2–3.52 GHz) and 17.5% (3.86–4.6 GHz), respectively. The dual band can cover 3.3-3.6 GHz and 4.4-4.5 GHz for 5G bands proposed by China’s IMT propulsion group. Therefore, the proposed antenna can be widely used in wireless detection, transmission and communication. The isolation of low frequency band and high frequency band can reach above 26 dB and above 22 dB. The average gain is approximately 10.2 dBi in the low frequency band, but the other band is around 6.37 dBi. Compared with commonly used base station antennas, the proposed antenna has been dramatically improved in terms of size, bandwidth, and other electromagnetic properties.

A Mutual-Coupling-Suppressed Dual-Band Dual-Polarized Base Station Antenna Using Multiple Folded-Dipole Antenna

An interleaved shared-aperture dual-band dual-polarized base station array antenna is proposed in this article. The lower-band (LB) element is realized by using a multiple folded-dipole antenna (MFDA) and four parasitic loops. To interpret the working principle of the MFDA, a double folded-dipole antenna (DFDA) is firstly analyzed by using the transmission line (TL) model. Then, by combining two bended DFDAs and introducing four parasitic loops, a low cross-band scattering LB element with a high out-of-band rejection level of 16 dB is obtained to cover 2.3–2.7 GHz. The higher-band (HB) element with a wide impedance bandwidth of 42.5% (3.0–4.6 GHz), a high roll-off rate (RoR) of 249.2 dB/GHz, and a high out-of-band rejection level of 17 dB is obtained by introducing a meander line loop (MLL), a rectangular loop (RL), and V-shaped strips (VSS) near the dipole arms. By combining the proposed low-scattering low-pass LB element and the high- RoR high-pass HB element, a novel interleaved shared-aperture dual-band dual-polarized array antenna with a small frequency ratio of 1.46 and a high cross-band isolation level of 25 dB is realized. Due to the low-scattering characteristic and filtering response of the LB element, the radiation patterns of the wideband HB sub-arrays are almost unaffected.

Millimeter-Wave Dual-Band Dual-Polarized SIW Cavity-Fed Filtenna for 5G Applications

This article presents a millimeter-wave (mmWave) dual-band dual-polarized filtenna, which can achieve desirable out-of-band rejection for 5G applications. The dual-band dual-polarized antenna element consists of two fully-shielded quarter-mode substrate integrated waveguide (FSD-QMSIW) cavities and a dual-band stacked ring antenna. Two parts are coupled through the slot on the ground. The cavities are completely enclosed by the metal holes and copper cover to eliminate radiation loss. The loaded slots can tune the frequencies of the first two modes in the FSD-QMSIW cavity for dual-band operation. The inherent transmission null between the dual modes is generated to improve the stopband attenuation. To verify the proposed method, a dual-band dual-polarized filtenna with a three-order filtering function and four radiation nulls is designed and fabricated. The −10 dB impedance bandwidth can effectively cover 5G n258 (24.25–27.5 GHz) and n260 (37–40 GHz) bands in the measurement. The gains of two polarizations drop over 20 dB between the two bands. A four-element filtenna array is constructed to test its beam-scanning ability and further integrated with active beamformer integrated circuits (ICs). The measured results show that the fabricated filtenna array maintains satisfactory out-of-band rejection performance and can be one of the most promising 5G communication candidates.

Suppression of cross‐band scattering effect of shared‐aperture base station antenna by using sparse FSS

In this article, a method on suppressing cross-band scattering effect of dual-band dual-polarized shared-aperture antenna is proposed. The antenna consists of a lower-band (LB) element and a 2 × 2 higher-band (HB) array. The proposed LB element radiator is a pair of crisscross-shaped dipoles using sparse frequency selective surface (SFSS) which is composed of a rectangular ring and a rectangular inner patch. This LB element exhibits wave-transparent reducing blockage and interference for HB array and achieving reduction the radiation pattern distorting from cross-band scattering. The experimental results demonstrate that the cross-band scattering effect is suppressed. Compared to the HB array alone, the radiation patterns of the HB antenna with the proposed LB element are restored. The proposed dual-band dual-polarized shared-aperture antenna can meet the requirement of base station application for 2G/3G/4G/5G.

Compact Dual-Band Base-Station Antenna Using Filtering Elements

This communication presents a compact dual-band dual-polarized filtering antenna for base-station applications. The proposed dual-band antenna consists of a high-band (HB) dipole element and a low-band (LB) patch element, both with filtering responses. The HB element is embedded into the LB element, minimizing the overall size. The strong mutual coupling between the HB and LB elements is reduced by employing filtering HB and LB elements. For demonstration, a prototype of the dual-band antenna operating at LTE band 41 (2.5–2.7 GHz) as well as LTE bands 42 and 43 (3.3–3.8 GHz) is fabricated and measured. The antenna features a compact size of 41 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times\,\,41$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.52\,\,\lambda _{hh} \,\,\times0.52\,\,\lambda _{hh}$ </tex-math></inline-formula> , where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{hh}$ </tex-math></inline-formula> denotes the guided wavelength at the highest frequency of HB). The cross-band isolation is higher than 27 dB without using extra filtering or decoupling circuits. In addition, a measured average gain of 7.8 dBi in LB and 7.7 dBi in HB is achieved. These merits make the proposed antenna suitable for 5G multiband aperture-shared array application.

Artificial magnetic conductor‐backed dual‐band shared‐aperture antenna array for base station applications

A low-profile dual-band dual-polarized base station antenna array is proposed. The dual-band array is backed by an artificial magnetic conductor (AMC) surface. The AMC achieves profile reduction to 0.159 λL0 in the low band (LB), but it acts as a bandpass metasurface in the high band (HB). The nested design of AMC unit cell creates two out-of-phase induced currents with lower intensities, enabling suppression and cancelation of HB scattered fields. The back cavities establish clear and independent radiating environments for the LB and HB antennas. They aid in further radiation pattern restoration and antenna profile reduction. The proposed antenna array was fabricated and experimentally measured. The simulated and measured results are presented. The operating principles of the proposed AMC and back cavities are also investigated.

Self-Decoupled Dual-Band Dual-Polarized Aperture-Shared Antenna Array

This communication presents a self-decoupled dual-band dual-polarized aperture-shared antenna array. The proposed dual-band array consists of a low-band (LB) antenna element interleaved into a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 2$ </tex-math></inline-formula> high-band (HB) antenna array with compact elements spacing. To mitigate the blockage effect resulting from the LB element, shorted patches are loaded on the LB radiator for suppressing its scattering in the HB frequency range. In addition, high cross-band isolation between the closely spaced LB and HB elements is obtained due to their intrinsic filtering response. Moreover, the in-band mutual coupling between the HB elements is reduced by adding cross-shaped strips on them. As a result, the cross-band and in-band couplings and the antenna blockage effect can be simultaneously reduced without adding an extra decoupling component. A prototype of the proposed array operating in 1.71–2.17 GHz (LB) and 3.3–3.8 GHz (HB) is fabricated and measured. The radiation patterns of the LB and HB elements are almost unaffected by each other. Furthermore, all of the port-to-port isolations are higher than 20 dB. These merits make the proposed design suitable for the multiband base station.

Coplanar Dual-Band Dual-Polarized Shared-Aperture Antenna Array For 4/5G Base Station Applications

A novel dual-band dual-polarized shared-aperture antenna array is presented for fifth generation wireless communication application. This novel antenna array is a combination of a low-band antenna and four high-band antennas. In order to simplify the design model while achieving broadband, antenna working on low-band (from 0.68 to 0.99 GHz) and antenna working on high-band (from 3.3 to 5.1 GHz) are both loop-shape radiator fed by Y-shape feed. Coplanar, dual-band and shared-aperture are resolved by embedding four HB antenna elements in the LB antenna. From simulation, the proposed coplanar antenna array respectively achieves 43% (from 0.68 to 0.99 GHz) and 37% (from 3.3 to 5.1 GHz) impedance bandwidth in the low-band and high-band.

A Compact Wireless Passive Harmonic Sensor for Packaged Food Quality Monitoring

There is currently a need to monitor food products while preserving quality and safety during long-term storage. In this article, a compact low-cost quasi-chipless sensor for monitoring the quality of high-value food items, such as milk and meat products, is presented. The sensor utilizes a dual-band dual-polarized annular ring antenna with an integrated harmonic generator and sensor to receive, modulate, and retransmit the interrogator signal. The resonant frequency of the receiving mode of the antenna is sensitized to the parameter being sensed using a varactor—pH electrode-based transduction scheme. The received signal is doubled using a diode frequency doubler circuit to minimize the clutter from the environment before retransmission. One application of the sensor for monitoring pH is presented. The sensor was shown to be able to successfully monitor the milk souring process.

Dual‐band dual‐polarized shared‐aperture antenna with cross‐band scattering suppression

A dual-band dual-polarized shared-aperture antenna with suppression of cross-band scattering for base station application is presented in this article. The proposed antenna consists of a lower-frequency-band (LFB) antenna and two 1 × 3 higher-frequency-band (HFB) arrays. The LFB antenna is designed with a novel configuration. Some chokes composed of inductive and capacitive elements are introduced for scattering current suppression of the cross-band, which is the main reason for the deterioration of the radiation pattern of the HFB arrays. The measured results show that the LFB antenna with the operating frequency of 690–960 MHz and the HFB antenna with the operating frequency of 1710–2170 MHz achieve stable radiation characteristics in their respective bandwidth.

Frequency Selective Surface-Based Dual-Band Dual-Polarized High-Gain Antenna

This article presents a frequency selective surface (FSS)-based dual-band dual-polarized antenna with compact size and high gain. The proposed dual-band antenna consists of a low-band (LB) and high-band (HB) antenna elements. The HB element is coaxially located under the radiator of the LB element, minimizing the overall size. The proposed LB element consists of a two-layer-FSS-based radiator (FSS-radiator) and two pairs of differential feeding probes. Besides, the passband of the proposed FSS-radiator is designed to cover the operating band of the HB element. As a result, the radiation of the HB element can transmit through the FSS-radiator of the LB element. Without reducing HB element gain, instead, the average HB element gain can be improved more than 1 dB by the feeding probes of the LB element. For demonstration, a prototype of the dual-band antenna operating in the LB of 2.3–2.7 GHz and the HB of 3.3–3.8 GHz is fabricated and measured. The dual-band prototype features high gain (~9.1 dBi in the LB and ~8.6 dBi in the HB) in a compact radiation aperture of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.32\lambda _{lc} \times 0.32\lambda _{lc}$ </tex-math></inline-formula> or <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.45\lambda _{hc} \times 0.45\lambda _{hc}$ </tex-math></inline-formula> (where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{lc}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{hc}$ </tex-math></inline-formula> , respectively, denote the guided wavelengths at the central operating frequencies in LB and HB). Moreover, easy fabrication and low cost are achieved. These merits make the proposed antenna suitable for multiband aperture-shared array.

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 with Improved Isolation Characteristics for Polarimetric SAR Applications

A dual-band dual-polarized antenna with high isolation characteristics is proposed for polarimetric synthetic aperture radar (PolSAR) applications. The antenna consists of four dipole antennas and 2 × 2 patch antenna arrays operating at the P-band (450–730 MHz) and Ka-band (34–36 GHz), respectively. The dipole antennas and the patch antenna arrays need dual-linear polarization characteristics to acquire PolSAR data. Improvements in the isolation characteristics at the P-band are achieved by inserting a metamaterial absorber with a fractal geometry between the transmitting (Tx) and receiving (Rx) dipole antennas. Without the absorber, the simulated isolation characteristics between the Tx and Rx antennas are lower than 19.2 dB over the target band. On the other hand, with the absorbers, the simulated isolation characteristics are higher than 23.44 dB over the target band, and remarkable improvement is achieved around the resonance frequency of the absorber. The measured results are in good agreement with the simulated ones, showing that the proposed antenna can be a good candidate for PolSAR applications.

Coplanar Dual-Band Base Station Antenna Array Using Concept of Cavity-Backed Antennas

In this article, we propose a novel reflector-back cavity-low-band (LB)/high-band (HB) configuration for the dual-band dual-polarized base station antenna array design. The HB antennas are embedded in the opening sections of the loop radiating arms of the LB antennas. Clear and independent radiating environments are fulfilled by using two different types of reflectors (large planar reflector and back cavity). The mutual effects between the LB and HB antennas help to acquire good impedance matching and stable radiation patterns. Loop-like LB radiators work as directors in the HB, thereby effectively suppressing the side and back radiations of the HB antennas. Dual-function open slots are loaded on the ground stubs of the LB baluns, serving as impedance transformer in the LB but filtering structures in the HB. The experimental results validate that the proposed antenna array successfully covers bandwidths of 0.69–0.96 and 3.3–3.8 GHz (VSWR < 1.5) for 4G/5G applications. The port isolations are higher than 38 and 25 dB in the LB and HB, respectively. With the two independent radiating environments formed in the two bands, both LB and HB antennas exhibit stable unidirectional radiation patterns. The antenna gains and HPBWs are also satisfactory in both bands.

A Dual-Band Dual-Polarized Antenna for Small Base Station Applications

This paper proposes a dual-band dual-polarized antenna which can operate at both the 1.71–2.69 GHz band (3G/4G band) and the 3.3–3.8 GHz band (5G NR band 78). The main radiator (crossed dipoles) is meticulously designed to obtain the two desired bands of interest, and the fan-shaped feeding structures are used to obtain good impedance matching. The measured low band and high band operations was 49.8% (1.69–2.81 GHz, VSWR ≤ 1.5) and 14.8% (3.32–3.85 GHz, VSWR ≤ 2), respectively. The measurement results also show that this antenna has good isolation, stable radiation pattern, and good XPD.

A lower profile base station antenna: With dual‐polarization and dual‐band for sub‐6 GHz application

A compact dual-band antenna is designed in this paper, which consists of a pair of lower band (LB) element and four higher band (HB) elements operating at 0.69 to 0.96 GHz and 3.3 to 3.6 GHz, respectively. Four HB elements are put between the adjacent dipole arms of LB element. All of elements are at the same height, and having their own reflector. A designed dual-band dual-polarized antenna at high frequency ratio will be fulfilled without added any other structure. The fabricated antenna sample has been measured, results show that the average gains of LB and HB elements are 8.48 dBi and 8.44 dBi and the half power beam widths are 69.1° ± 9° and 60.7° ± 8.5°, respectively. Moreover, dual-polarized property of both LB and HB is checked. The cross-polarization discrimination values are greater than 15 dB. The proposed antenna is implemented the coverage of two bands with high frequency ratio with a simple structure, and the antenna with both low profile and high gain characteristics. All of the results demonstrate that the antenna radiation boasts its favorable performance and can be a good candidate in 5G mobile communication system for sub-6 GHz base stations.

Dual-Band Shared-Aperture Base Station Antenna Array With Electromagnetic Transparent Antenna Elements

An electromagnetic transparent antenna element is proposed for dual-band shared-aperture fifth-generation (5G) MIMO base station antenna array developments. The antenna element that operates in the low-frequency band (LB) of 1.8-2.7 GHz is placed above the aperture of the antenna array that operates in the high-frequency band (HB) of 3.3-3.8 GHz. Because of this antenna array configuration, the antenna elements in the LB have to be transparent to the electromagnetic waves radiated by the HB antenna array. This kind of electromagnetic transparent antenna element allows the HB antenna array working properly in the dual-band shared-aperture antenna array configuration. In this work, the electromagnetic transparent antenna element is inspired by the element of a typical wide-angle bandpass frequency selective surface (FSS). The radiation performance of the electromagnetic transparent antenna element at the LB is realized by properly combining the wide-angle bandpass FSS elements. A dual-band dual-polarized shared-aperture antenna array is then developed to demonstrate the concept and design. The experimental result validates the stable radiation patterns of each antenna element in both LB and HB. It indicates the proposed approach is promising for 5G MIMO base station antenna array developments.