Dual-polarized Antenna Research Articles

Wideband Dual-Polarized Hollow-Waveguide Slot Array Antenna

A wideband dual-polarized slot array antenna based on hollow waveguide (HW) is presented in this article. Its wide bandwidth and high performance are enabled by two separate feeding networks, from the side and the bottom, using square coaxial line and ridge waveguide structures, respectively. The full-corporate-feed networks excite the radiation slots in a one-to-one fashion without using backed cavities. Tight element spacing is made possible, suppressing the grating lobe and maintaining high cross-polarization discrimination (XPD) across the wideband. This resolves a usual tradeoff between bandwidth and grating lobe. A double-ridge rectangular waveguide cavity is devised as an orthogonal mode splitter for isolation enhancement. Several design features are used to minimize the signal path length and facilitate routing. An <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times8$ </tex-math></inline-formula> element prototype in K-band is designed, fabricated, and measured. Experimental results show that the antenna has a wide bandwidth of 23.4% (from 17 to 21.5 GHz) free from grating lobes. More than 25.5 dBi peak gain higher than 51.2 dB isolation and over 43.6 dB XPD are also obtained for the dual polarizations.

Planar dual-polarized millimeter-wave shared-aperture array antenna with high band isolation

Planar dual-polarized millimeter-wave shared-aperture array antenna with high band isolation

Bandwidth Enhancement of a Compact Dual-Polarized Antenna for Sub-6G 5G CPE

An ultrawideband dual-polarized antenna for fifth generation (5G) customer premise equipment is investigated and designed in a compact environment by using a double-loop-dipole structure and a co-planar-slot feeding concept. First, the existing design of dual-polarized octagonal loop dipoles is introduced at first. Then, a novel double-loop-dipole structure and co-planar-slot feeding are proposed and demonstrated in detail from the current distribution and physical structure sides. Finally, the proposed antenna is designed, fabricated, and measured. The measured results present that the proposed antenna has a wide bandwidth of 86% from 2.2 to 5.5 GHz with the VSWR less than 1.8, high polarization isolation of 25 dB, and stable radiation patterns over the desired frequencies of 2.3–5.2 GHz. It is worth mentioning that the proposed ideas can effectively aid in impedance bandwidth improvement without adding additional cost for sub-6G 5G applications.

A Transparent Wideband Dual-Polarized Antenna for Sub-6 GHz Application

In this letter, a novel transparent dual-polarized antenna has been developed for sub-6 GHz application. The proposed antenna composed of transparent conductive mesh and polycarbonates material is of optical transparency. Based on characteristic mode analysis, the proximity-coupling fed driven patch operates in TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> /TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> mode. By stacking the parasitic patch and strips above the driven patch with a cross slot, three resonances are generated. With the T-shaped slots on the parasitic patch, the impedance matching at low frequencies is improved. By etching the slots on the ground and cutting off the corners of the driven patch, good port isolation and stable in-band gain are achieved. The prototype of proposed antenna is fabricated. The measured results show that the proposed antenna exhibits a wide impedance band of 2.76–4.13 GHz with a fractional bandwidth of 39.8%, a good isolation better than 22 dB, a low cross polarization ratio better than 20 dB within the operating band.

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.

A weighted GPS positioning algorithm for urban canyons using dual-polarised antennae

ABSTRACT The positioning performance of the Global Positioning System (GPS) is severely degraded in urban canyons due to buildings blocking or attenuating signals. This paper proposes a weighted GPS positioning method using a dual-polarisation antenna in order to deal with this issue. The GPS signals are first classified and labelled into NLOS signals and LOS/MP signals by considering the right-hand circular polarised (RHCP) and the left-hand circular polarised (LHCP) signal strengths. Then, a Bayesian optimisation-based Gaussian process is used to fit the pseudorange error related to the input of the carrier-to-noise ratio of the RHCP QUOTE() and the elevation angle of the LOS/MP signals. The pseudorange errors of the LOS/MP signals are therefore predicted based on the rules extracted from the fitting results. The positioning solutions are then obtained from the weighted least-squares algorithm, with the weighting strategies being based on the predicted pseudorange errors. Static positioning results in deep urban areas showed that the horizontal root-mean-square error (RMSE) positioning has been improved by 64.6% and 57.3%, respectively, while 3D RMSEwas improved by 74.3% and 48.1%, respectively, compared with traditional single-point positioning results.

Electromagnetic Performance of Waveguide Polarizers with Sizes Obtained by Single-Mode Technique and by Trust Region Optimization

Modern wireless networks, stationary terrestrial and satellite systems use many modern technologies to increase communication channels information capacity. They save limited frequency resources. In satellite communications the polarization signal processing is applied to reuse the allocated frequency bands. Usage of circularly polarized electromagnetic waves, which transmit useful signals, reduces fading effects and eliminates disadvantages introduced by multipath propagation interferences. In this case the distortion levels for signals with an odd number of electromagnetic waves reflections in the receiving antenna systems will be reduced down to the thresholds of their cross-polarization isolation. Besides, in the case of orthogonal polarizations usage, the achieved information capacity of the applied wireless communication channel multiples almost by the factor of two. The type of polarization of the used electromagnetic wave strongly determinates the peculiarities of the process of its propagation in the space or transmission line. Polarization signal processing is frequently carried out in horn feed systems of the reflector antennas. Such feed networks and systems allow to transmit and receive signals with several kinds of polarization at the same time. The fundamental element of dual circular polarization antenna feed networks is a waveguide polarization duplexer. The phase, isolation and matching characteristics of a polarization converter strongly influence on the functionality and polarization discrimination possibilities of the entire reflector antenna system. Therefore, the development and optimization of the characteristics of waveguide polarizers for satellite communication antennas is a crucial technical problem, which must be solved by fast and accurate methods. The comparison of electromagnetic performance of waveguide polarizers with sizes obtained using a fast single-mode technique and by more accurate trust region optimization method is carried out in this research. The results for differential phase shift, level of voltage standing wave ratio, ellipticity coefficient and cross-polarization discrimination are shown and discussed.

Dual-Polarized Wide-Angle Scanning Phased Array Antenna for 5G Communication Systems

A dual-polarized phased array antenna is presented with wide-angle scanning capability in this article. To improve the mutual coupling in the array, a current cancellation method (CCM) is proposed by changing the current distribution on the excited unit to induce a pair of the canceled currents on the adjacent unit. Meanwhile, this current distribution broadens the beamwidth of the unit in the array. Besides, the proposed method can also optimize the array unit size and achieve a small inter-unit distance for wide-angle scanning capability. A low-profile dual-polarization antenna operating in the bandwidth from 4.4 to 5.0 GHz is designed as a linear array and a planar array to verify the proposed method. Regardless of the linear array or planar array, the mutual coupling in the array is below −19 dB, which is better than that in conventional arrays. Meanwhile, the antenna unit in the array can radiate a wide-beam pattern. Two arrays can scan over ±60° for both polarizations. Within the scanning range, the realized gain reduction is less than 3 dB and the sidelobe level is lower than −7.5 dB. To verify the performance, two array antenna prototypes are fabricated and tested. The experimental results agree well with the simulation.

Low-Profile Dual-Polarized Multi-Beam Antenna Based on Pillbox Reflector and 3D-Printed Ridged Waveguide

In this article, a dual-polarized multibeam antenna is proposed. Two orthogonally polarized slotted waveguide antennas (SWAs) are cross-placed as the main radiator, which is designed based on ridged waveguides (RGWs) to reduce the width of the waveguides and obtain a wider steering range. The two SWAs are fed by two pillbox reflector beamforming networks (BFNs), and a special impedance transition is designed to reduce the reflection between the quasi-TEM wave in the parallel-plate waveguide (PPW) to the TE10 wave. By exciting different feeding patches in the focal planes of the pillbox reflectors, the SWA achieves different beams. In order to further increase the crossover level, the single-port excitation (SPE) and the dual-port excitation (DPE) method are used together to increase the equivalent source number in the compact area of the focal plane. Besides, the DPE method can also reduce the sidelobe level (SLL) of the beams excited by the side ports. A prototype is designed at the operating frequency of 10 GHz and fabricated by the 3-D-printed technology and computer numerical control (CNC) technology. The measured results show that the proposed antenna achieves ± 36° beam scanning in the multibeam plane with the minimum crossover level of −2.1 dB. The cross polarizations are below −20.0 and −15.9 dB for the horizontal polarization (H-P) and the vertical polarization (V-P), respectively. The advantages of dual polarization, high aperture efficiency, low cross polarization, wide beam scanning range, and low crossover level make this antenna a very appropriate choice in multibeam radars and communication systems.

A Dual-Polarized Wideband Ceiling-Mount Antenna With Low Gain Variations and High Isolation for 5G Sub-6 GHz Applications

A dual-polarized wideband omnidirectional ceiling antenna with low gain variations (GVs) for 2G/3G/LTE/5G sub-6 GHz indoor applications is presented. The vertical-polarized (VP) antenna element that is arranged in the center is composed of a pair of orthogonal semicircular plates and a top-loaded circular brass disk, whereas the horizontal-polarized (HP) antenna element is comprised of four printed dipoles with truncated corners, four arc-shaped parasitic patches around the dipoles, and a 1-to-4 power divider feeding network on the bottom. The feeding network with the “hook”-shaped stubs cooperates with the slot between the adjacent printed dipoles to improve the isolation between the VP and HP antenna elements. Furthermore, the top-loaded circular brass disk, the four arc-shaped parasitic patches, and two pairs of extended strips printed along the ±45° direction are used to reduce the GVs but broaden the operating bandwidths. Experimental results demonstrate that a wide overlapped frequency bandwidth of 74.9% (1.66–3.65 GHz) with an excellent port isolation (≥40 dB) is achieved for the aforesaid application scenarios.

A Wideband Dual-Polarized Ring-Loaded Cross Bowtie Antenna for Wireless Capsule Endoscopes: Design and Link Analysis

This work presents a novel on- body wideband dual-polarized antenna to stabilize and enhance the link performance of wireless capsule endoscopy systems. By introducing a cross-bowtie structure with a planar compact feed method, the antenna achieves a dual-polarized performance with high port-to-port isolation. A loaded ring with additional stubs is also implemented to further enhance the bandwidth and provide a flat in-band performance from 381 to 990 MHz. The proposed antenna is measured with both homogeneous phantom and ex vivo test to validate the impedance matching performance. To validate the effectiveness of the proposed on- body antenna on the communication link, a capsule helical antenna with omnidirectional radiation pattern is designed and measured. Finally, comprehensive link studies are conducted considering the varied capsule orientations and locations, with a peak <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\vert S_{21}\vert $ </tex-math></inline-formula> value of–25.5 dB at the 60 mm implant depth and an acceptable link loss due to the capsule position error. The proposed on- body antenna can be regarded as a good candidate for a practical capsule endoscopy system due to its stable and enhanced transmission performance when compared with its counterparts.

A Wideband Dual-Polarized Magneto-Electric Dipole Transmitarray With Independent Control of Polarizations

This communication presents a dual-polarized transmitarray antenna with wide bandwidth and independent beam control for each polarization. A new low-insertion-loss transmitarray element allowing wideband dual-polarized operation is proposed by using magnetoelectric (ME) dipole with shared radiating structure and interleaved orthogonal feeding probes; 1 bit phase adjustment can be realized individually for each polarization with additional freedom in manipulating the cross-polarization over a fractional bandwidth of 23%. Three transmitarrays that achieve possibly different collimated beams and/or cross-polarization manipulation are designed and carried out at millimeter-wave frequencies covering from 23.5 to 32.5 GHz. Measurement results of the prototypes agree reasonably well with simulations, which validates the wideband operation and independent beam controls.

Solving Sub-Wavelength Lattice Reduction in Full-Metal Front-Ends for Dual-Polarized Active Antennas

This article proposes an original structure of evanescent quadridge antenna (EQA) to conceive dual-polarized full-metal front-ends that can be used in active antennas (AAs) with wide field-of-view (FoV). An original design methodology is here proposed that allows to induce radiation from subwavelength squared apertures based on the use of evanescent and quadridge waveguides. The proposal is illustrated by means of a design with 4.5% bandwidth providing dual-circular polarization (CP) with good performance up to 50°-scanning even in the diagonal plane. For comparison purposes, a metallic benchmark is also proposed, which is based on the use of classical quadridge horns. Such comparative analysis allows to understand the superior performance of the proposed concept and its main advantage: it allows to avoid the excitation of the first high order mode in the squared quadridge aperture. The excitation of such spurious mode in the antenna is explained in terms of simple equivalent circuit models characterizing the aperture periodic discontinuity.

Differentially Fed Dual-Polarized 2-D Multibeam Dielectric Resonator Antenna Array Based on Printed Ridge Gap Waveguide

In this article, a differentially fed dual-polarized dielectric resonator antenna (DRA) subarray excited by a substrate integrated waveguide (SIW) cavity is proposed. A #-shaped slot etched on the top wall of the SIW cavity is used to achieve the differential excitation due to the intrinsic field distribution of TE120 mode in the SIW. Based on the proposed antenna subarray, 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 $ </tex-math></inline-formula> 2 dual-polarized 2-D multibeam DRA antenna array with simple structure is designed, fabricated, and measured, which can achieve high cross-polarization discrimination (XPD) in the direction of maximum radiation. To reduce substrate loss, the printed ridge gap waveguide (PRGW) technology is used to feed the SIW cavity. Two orthogonal PRGW Butler matrices are placed at different layers so as to realize 2-D beamforming scanning with dual-polarization. The SIW cavity is placed in the air gap of PRWG, which can increase the stability of the antenna structure. By cleverly combining the SIW cavity and PRGW structure, the proposed multibeam antenna array has the advantages of high XPD and high radiation efficiency. Measured results show that an impedance bandwidth of 10% (28.5–31.5 GHz) and a peak gain of 11.8 dBi are obtained. Also, the measured XPDs are 28.3 dB at the center frequency and larger than 19.2 dB over the band of operation. Besides, the measured radiation efficiency of 67% is achieved for both the polarizations at 30 GHz.

Low-Profile and Shared Aperture Dual-Polarized Omnidirectional Antenna by Reusing Structure of Annular Quasi-Dipole Array

A low-profile and shared aperture dual-polarized (DP) omnidirectional antenna by reusing the structure of an annular quasi-dipole array is presented. The proposed antenna consists of a center-fed circular patch antenna, an annular quasi-dipole array, a wideband one-to-four power divider integrated with the center-fed circular patch antenna, and two annular strips. The center-fed circular patch antenna is utilized as the driven element for the vertically polarized (VP) radiation. The annular quasi-dipole array fed by the one-to-four power divider produces horizontally polarized (HP) radiation. Simultaneously, it also acts as the VP director to improve VP gain and bandwidth. Besides, the two annular strips enhance the HP omni-directivity and gain. In this way, the VP and HP share the same aperture to improve the profile utilization rate effectively. Due to the symmetry of the basic antenna structure, stable DP donut patterns are obtained within the entire operating bandwidth. For demonstration, a 4.1–5.0 GHz prototype is designed, fabricated, and measured. Under a low profile of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.13\lambda _{0}$ </tex-math></inline-formula> , the prototype realizes a −10 dB overlapped bandwidth of 20%, high port isolation of above 35 dB, and stable DP donut patterns with horizontal gain larger than 1.8 dBi.

Multiband Dual-Polarized Hybrid Antenna With Complementary Beam for Simultaneous RF Energy Harvesting and WPT

A novel hybrid antenna for simultaneous RF energy harvesting (RF-EH) and dedicated wireless power transfer (WPT) is proposed. The hybrid antenna consists of a multiband dual-polarized omnidirectional antenna element (covering GSM-1800, UMTS-2100, ISM-2400/5800, 5G-3500, and wireless local area network (WLAN) bands) and a 2.4 GHz dual-polarized high-gain directional patch array element. In the WPT band (ISM-2400), directional beams locate at the null of omnidirectional beams, and a pair of spatially complementary beams is obtained. The omnidirectional beams are capable of capturing the ambient RF energy from low-elevation space for low-power circuits, while the directional beams receive the power from a dedicated source to activate high-power modules. Also, the spatially complementary feature contributes low mutual couplings between ports that support the independent operation of WPT and RF-EH. For validation, an outdoor RF-EH test and an indoor WPT test are conducted. The measured results agree with the simulated ones.

A Compact Wideband Dual-Polarized Antenna Using Monolithic Dielectric for 5G Base Station Application

A compact wideband dual-polarized dielectric resonator antenna (DRA) is investigated in this letter. The antenna is formed by a monolithic cross-shaped dielectric block with a rectangular part for support and two pairs of orthogonal metal strips printed on the bottom of the cross dielectric. For demonstration, a dual-polarized prototype antenna with the electrical size of 0.38 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.38 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.14 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> has an impedance bandwidth of 16.5% from 3.25 to 3.85 GHz with | <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | < −15 dB covering the N78 band for fifth-generation (5G) new radio. Furthermore, the antenna has a stable gain of 8.5 ± 0.4 dBi across the operating frequency range, demonstrating the high stability of the radiation characteristic for the two radiation modes. All the simulated and measured results for the DRA are given, showing a good agreement.

Beam Scanning for Dual-Polarized Antenna With Active Reflection Metasurface

In this letter, a dual-polarized antenna with steerable beam is presented. The antenna consists of an active reflection metasurface and a cross dipole antenna. The beam scanning of the antenna is obtained by tuning the capacitance of the varactor diodes mounted on the active reflection metasurface cell. A reflection phase covering 300° can be obtained by tuning the capacitance value. The air layer in the middle of the reflection unit makes the reflection phase curve flat and achieve a stable phase difference over a wide band. Moreover, the cross-shaped structure of the reflection unit can manipulate the reflection phase of the electromagnetic waves with two polarizations. Therefore, the dual-polarized antenna can maintain good radiation performance and port isolation while the beam is deflected. The simulated radiation efficiency is higher than 88%. The measured results demonstrate that the beam-steering range is ±20°, short for voltage standing wave ratio (VSWR) is less than 1.7 and the port isolation is greater than 20 dB in the frequency range of 3.3–3.6 GHz.

Broadband Dual-Polarized Aperture-Coupled Patch Antenna for 5G Applications

Abstract: This paper presents the design of a dual-polarized aperture-coupled microstrip antenna array for Sub-6GHz 5G communication systems. The antenna operates at 3.5 GHz and consists of 4×4 square patches. The proposed 4×4 array antenna feds by aperture-coupled feed line provide broadband bandwidth to operate in the N78 sub-6GHz 5G frequency band. The dualpolarized is presented, which gives two communications channels. The antenna consists of three layers and is designed on Rogers RO4003C substrate with a dielectric constant of 3.55 and substrate thickness of 0.8 mm. The final design of the antenna array with an overall size of 269 mm × 269 mm × 12.5 mm, and the results show that the 4×4 array has a 10dB bandwidth between 3.3-3.8 GHz and a maximum gain of 14.9 dB at 3.5 GHz, and the isolation between the two ports was 30 dB. The proposed antenna's gain, radiation efficiency, and bandwidth satisfy the requirements of 5G base station systems.

1-Bit dual-polarized ultrathin lens antennas based on Huygens’ metasurface

In this paper 1-bit dual-polarized ultra-thin lens antennas are presented based on Huygens’ principle. The unit cell provides two-state transmission phase compensation for dual-polarized waves. By tuning state 0 away from resonance and state 1 near Huygens’ resonance, the 180° transmission phase difference between the two states is achieved. In the frequency range of 27.5–28.5 GHz, the transmission phase difference between the two states of the unit cell is 180° ± 20°, and the transmission amplitude is greater than −2 dB. Using the proposed unit cell, three ultrathin 1-bit Huygens’ metasurface antennas comprising 33 × 33 unit cells with single beams pointing separately at 0°, 15°, and 30° are designed, fabricated and measured. Simulated and measured results show that the proposed 1-bit transmitarray antenna can achieve single-beam patterns, which is useful for the development of reconfigurable transmission and digital metasurface antennas in the future.