Magneto-electric Dipole Research Articles

Dual-Band Linearly and Circularly Polarized Unidirectional Hybrid Loop/Magnetoelectric Dipole Antenna With Single Feeding

A dual-band linearly polarized (LP) and circularly polarized (CP) unidirectional hybrid antenna is proposed in this article. The antenna consists of a cross slot antenna (CSA), a pair of vertical and horizontal metal plates, two side walls, and a cavity reflector, fed by a simple single feeding structure. In the lower frequency band, a loop antenna operating in $1\lambda $ mode is formed by the ground of the CSA, a pair of horizontal plates, and two side walls, to generate the LP radiation. In the higher frequency band, the cross slot works as a magnetic dipole (M-dipole), while the horizontal plates work as an electric dipole (E-dipole). With the appropriate combination, the magnetoelectric (ME) dipole produces an inherent 90° phase difference for the two orthogonal $E$ -fields to achieve CP radiation. The $1\lambda $ modes of the M- and E-dipoles are excited to realize the wideband CP bandwidth. Simulation and measurement are used to study and design the hybrid antenna. The results show that the proposed antenna has an impedance bandwidth (IMBW) of 2.38–2.50 GHz (0.12 GHz, 4.9%) for the LP radiation, and an IMBW of 4.63–7.37 GHz (2.74 GHz, 45.7%) and 3 dB axial ratio bandwidth (ARBW) of 4.10–6.60 GHz (2.5 GHz, 46.7%) for the CP radiation. The radiation patterns at dual bands are stable toward the broadside, having peak gains of 5.75 dBi and 7.53 dBic within the low and high frequency bands.

Wideband and Low Cross-Polarization Transmitarray Using 1 Bit Magnetoelectric Dipole Elements

The application of magnetoelectric (ME) dipole to achieve wideband and low cross-polarization transmitarray design is presented in this article. First, a novel meandering-probe-fed ME dipole that exhibits a wideband matching, central feeding configuration, and symmetrical antenna structure is developed. These preferred features are borrowed to address the narrowband and potential element-displacement issues in 1 bit transmitarray element design. Numerical simulations of the proposed 1 bit ME-dipole transmitarray element show a wide 1 dB insertion-loss bandwidth of 47% and a low cross-polarization level of −40 dB. Measured results of the transmitarray designed using the proposed ME-dipole elements indicate an operating bandwidth of 47% and a cross-polarization discrimination (XPD) around 35 dB. In addition, a dual-layer phase compensation scheme for cross-polarization synthesis is described. The effectiveness of this method is demonstrated with a cross-polarization cancelation scheme that further improves the measured XPD to 40 dB. The proposed transmitarrays show advantages of remarkable bandwidth, low cross-polarization, and comparatively high aperture efficiency over most reported 1 bit designs.

A High-Gain Millimeter-Wave Magnetoelectric Dipole Array With Packaged Microstrip Line Feed Network

A millimeter-wave 4 × 4 magnetoelectric (ME) dipole antenna array using a packaged microstrip line feed network is proposed. This antenna array features a wide impedance bandwidth of more than 50% and small back radiation. Each ME dipole element is excited by an L -shaped probe and each L -shaped probe is connected to the packaged microstrip line through a small hole in the ground plane. The packaged microstrip line forms the whole corporate feed network for the antenna array. The entire antenna structure is realized by multiple printed circuit boards (PCBs), which is low in material cost and easy in fabrication. The results demonstrate that the proposed antenna array enables the impedance bandwidth of 51.5%, high gain up to 20.3 dBi, and stable broadside radiation pattern with small back radiation over the operating frequencies. The array is suitable for the 5G application.

Millimeter-Wave Broadband Substrate Integrated Magneto-Electric Dipole Arrays With Corporate Low-Profile Microstrip Feeding Structures

A millimeter-wave (mm-Wave) broadband linearly polarized (LP) substrate integrated magneto-electric dipole (ME-dipole) with a low-profile microstrip feeding structure covering the 22–33 GHz band is proposed in this article. It owns a good performance, particularly in terms of bandwidth and gain flatness. Importantly, the proposed substrate integrated LP ME-dipole element can be easily expanded into a full-corporate fed array without bandwidth degradation and requiring additional dielectric substrates. Moreover, its low-profile microstrip feeding structure locating on a hybrid substrate (include a thin dielectric substrate and a bonding film) makes the antennas amenable for direct integration with mm-Wave front-end circuits. Design, fabrication, and measurement of two arrays containing $4 \times 4$ and $8\,\, \times \,\, 8$ ME-dipoles are carried out, respectively. The measured results agree well with the simulated ones, validating the correctness of the proposed designs. The measured results of the $4 \times 4$ and $8\times 8$ array antennas show that both the two prototypes exhibit a wide available bandwidth (considering |S11| < −10 dB and 3 dB gain bandwidth) of more than 44%, a cross-polarization level of lower than −35 dB, a low-profile feeding layer of only 0.227 mm, a peak gain of 19.18 and 25 dBi, respectively, etc. The exhibited performance metrics of the proposed array antennas are promising for a number of applications ranging from 5G communications, satellite communications, to automotive radars, and so on.

Low profile broadband substrate‐integrated waveguide to rectangular waveguide transition for W‐band automotive radar

Low profile broadband substrate-integrated waveguide to rectangular waveguide (RWG) transitions have been proposed for RF verification of W-band automotive radar. The transition is designed on a PCB, which is assembled between the radar board and instrument waveguide port. In the design of the transition, a magnetoelectric (ME) dipole is introduced to excite the basic mode of RWG, and a bowtie slot is designed to excite the ME dipole with a broadband performance. The measured frequency band of back-to-back transitions is 68.4–85.3 GHz for a 5 mil RO3003 covered multilayer radar board and 68.6–89.3 GHz for a 10 mil RO3003 covered board, respectively. The calibrated single transition loss is 0.58 and 0.33 dB, respectively. The proposed low profile transitions are robust to assembly errors and convenient for fast RF verification of automotive front-end in the design stage.

A Compact Wideband Circularly Polarized Magneto-Electric Dipole Antenna Array for 5G Millimeter-Wave Application

A compact wideband circularly polarized (CP) magneto-electric (ME) dipole antenna array is proposed. In order to achieve compact size and wideband characteristics, a novel substrate integrated waveguide (SIW) to coaxial transition (SCT) was designed to connect the lightning-shaped ME-dipole antenna element and an SIW feeding network. Particularly, an SCT-based power divider network together with the sequential-rotation (SR) technique was employed to improve the axial ratio (AR) bandwidth of the $4\times 4$ antenna array. The antenna array prototype was fabricated to verify the design. Measured results show that an impedance bandwidth of 27.7% (23.3–30.8 GHz) and 3 dB gain bandwidth of 25.3% (23.5–30.3 GHz) were achieved. Moreover, a 3 dB AR bandwidth of 27.8% (23.2–30.8 GHz) with a peak gain of 20.2 dBic was also recorded. Therefore, it is a good candidate for the fifth-generation (5G) millimeter-wave (mm-wave) communications.

Millimeter-Wave Magneto-Electric Dipole Antenna Array With a Self-Supporting Geometry for Time-Saving Metallic 3-D Printing

A specially designed millimeter-wave high-gain wideband magneto-electric (ME) dipole antenna array based on metallic 3-D printing technology is presented. In order to shorten the printing duration of the array that is related to the fabrication costs, components with novel self-supporting geometries in the printing process, including a waveguide-fed ME-dipole radiating element, a 1-to-4 power divider acting as the subarray feed, and a full-corporate E-plane waveguide feed network, are investigated. Benefitted from these components, the entire array configuration can be fulfilled by employing a time-saving printing scheme, which leads to a 15% reduction in the printing duration for an $8 \times 8$ array, and the reduction can be further increased to 40% for a $16 \times 16$ design in comparison with the reported 3-D printed Ka-band arrays with same sizes that were fabricated by using the traditional printing scheme. Simultaneously, excellent operating characteristics, including a wide bandwidth of 32.4%, a maximum gain of 27.1 dBi, and stable unidirectional radiation, are also confirmed experimentally by an $8 \times 8$ prototype of the proposed array. This work offers a method to effectively reduce the printing time of the 3-D printed large-size antenna arrays with attractive performance, which would be of importance to the practical cost-effective large-scale applications in the emerging millimeter-wave wireless communications.

A Magneto-Electric Dipole Antenna Array for Millimeter Wave Applications

In this paper, a low-profile broadband antenna is proposed for future 5G millimeter-wave cellular wireless networks. The proposed antenna is a modified Magneto-Electric (ME) dipole, which consists of four metallic plates, grounded vias, an aperture fed, a ground plane, and a microstrip line feed. The antennas are built on RT/Duroid 5880 substrates and have been realized by the printed circuit board technique. A single-element with an overall of 10×10×1.04mm3 (~1.26λo×1.26λo×0.13λo at 38GHz) exhibits an impedance matching of 27.9% (32.2-42.8GHz) for |S11|&lt;–10dB and a realized gain up to 7.5dBi over the frequency band. The usefulness of these antennas as beamforming radiators is demonstrated by a 1×4 element linear array. Also, a wide-band excitation is applied for the linear ME dipole array to realize a broadband array. The simulated results proved the proposed array can operate in a frequency band spreading from 31.4GHz to 42.1GHz with a gain of 12.5dBi and a side-lobe of -13dB

Design of a wideband substrate integrated waveguide antenna with high‐gain employing two bow‐tie‐shaped slots

In this work, a compact antenna employing the substrate integrated waveguide (SIW) technology is investigated to achieve the characteristics of wideband and high gain. A pair of novel elliptical patches, which operate as an electric dipole, are loaded on the upper surface of the antenna. Two bow-tie-shaped slots are etched in parallel on the upper surface of SIW to obtain the features of magneto dipole and wideband. Combined with the low profile character of the SIW, the low cost of printed circuit board technology and the broadband characteristic of magneto-electric (ME) dipole, a 1 × 8 SIW ME-dipole antenna array is proposed and fabricated. The experimental result of the proposed prototype shows that the 10 dB impedance bandwidth is 42.3% from 19.4 to 29.8 GHz, which is basically consistent with the simulated result. Moreover, the antenna gain up to 14.6 dBi and the radiation efficiency higher than 82.6% are also obtained during the experiment. In the whole resonance band, excellent directional radiation, cross-polarisation level <−25 dB and gain fluctuation <2.7 dB all suggest that the array can be applied to a fifth-generation wireless network.

A wideband dual-polarized antenna using magneto-electric dipoles for base station applications

Design and investigation of a new configuration of wideband dual-polarized magneto-electric dipole (MED) antenna for 2G/3G/4G base station applications operating from 1.7 to 2.7 GHz is presented. Two pairs of single-polarized MED antennas are arranged adjacent to each other to produce ±45° dual-polarization. Each pair of dipoles excited through a 3-dB power divider fed by a coaxial cable and a ground plane employed under the dipoles with the distance of λ/4 to produces a metallic reflector, which leads to unidirectional radiation patterns. Consequently, the proposed two-port base-station (BTS) antenna yields bandwidths of 1190 MHz (1.64 GHz–2.83 GHz) and 1060 MHz (1.67 GHz–2.73 GHz) for port-1 and −2 respectively with isolation better than −20 dB between the ports. Twelve metallic ground walls surround the radiators to achieve stable radiation properties across the operating frequency band. Subsequently, the dual-polarized antenna achieves half-power beamwidths (HPBWs) of about 61°, 65°, and 70° at frequencies of 1800 MHz, 2000 MHZ, and 2300 MHz respectively and realized peak gain of around 10.29 dBi for port-1 and 10.27 dBi for port-2 within the operating frequency band. A prototype of the proposed dual-polarized BTS antenna fabricated and tested with a good agreement between the measurements and simulations.

Compact High-Gain Si-Imprinted THz Antenna for Ultrahigh Speed Wireless Communications

A low-profile and high-gain Gaussian beam antenna (GBA) operating at 1 THz is demonstrated for the first time. Imprint and dry etching technologies in silicon are employed. A complementary antenna feed based on the magnetoelectric dipole is proposed for enhancing the radiation characteristics of the antenna. The microfabrication technologies are compatible with the Si-based integrated circuit manufacturing process. The terahertz (THz) antenna is realized with over 20 dBi in antenna gain. With high-precision fabrication technologies, a highly efficient THz GBA with smooth morphology and much lower profile than conventional horn and lens antennas is developed. Moreover, the antenna has the characteristic of low sidelobe levels which is advantageous in many wireless applications.

Low-Cost Millimeter-Wave Circularly Polarized Planar Integrated Magneto-Electric Dipole and Its Arrays With Low-Profile Feeding Structures

A low-cost millimeter-wave circularly polarized (CP) planar integrated magneto-electric dipole (ME-dipole) element with simple structure is proposed, which is fed by a low-profile feeding structure capable of being directly integrated with Ka -band front-end circuits. Two rotationally symmetrical L-shaped patches are adopted to replace the two straight arms of the original linearly polarized ME-dipole to generate a rotated electric field, thus radiating CP waves. Based on this CP ME-dipole element, CP array antennas containing 2 × 2 and 4 × 4 radiators with low-profile full-corporate feeding networks are developed without any additional dielectric layer. Prototypes of these two CP array antennas are fabricated and measured. Good agreement between the simulated and measured results is achieved, validating the correctness of these two designs. The 2 × 2 array exhibits a | S 11| Ka -band satellite communications, etc.

Wideband Widebeam Dual Circularly Polarized Magnetoelectric Dipole Antenna/Array With Meta-Columns Loading for 5G and Beyond

A dual circularly polarized (CP) magnetoelectric dipole antenna is presented in this article. The dual-CP antenna was devised to form a circular ring shape and fabricated using 3-D printing technology. To overcome the conflict between high (broadside) gain and wide (half-power) beamwidth, a new beamwidth broadening technique was proposed. Twelve metacolumns were placed evenly along the circumference close to the ring-shaped dipole. A design approach is elaborated, where the number and size of meta-columns were decided according to the design curves. Symmetrical beamwidth of 108° in orthogonal planes with a broadside gain of 6 dBic was achieved across a wide effective bandwidth from 3.2 to 5.4 GHz (51%), sufficiently covering the 5G new radio (NR) bands: n77, n78, n79. The antenna owns a compact size of 0.83×0.83×0.18 λ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> at 4.15 GHz. A planar subarray composed of four dual-CP elements was also investigated and compared with the existing arrays.

High Gain and Wideband Metasurfaced Magnetoelectric Antenna for WiGig Applications

This communication presents a high gain wideband metasurfaced magnetoelectric dipole for wireless gigabit (WiGig) applications. The proposed antenna achieves wide bandwidth and low cross-polarization. In addition, peak gain is increased by employing a metasurface (MS) which is working as a partially reflective surface. The proposed idea is numerically and experimentally demonstrated. Full-wave analysis shows 10 dB impedance bandwidth of 53.47-80.26 GHz, corresponding to 40.5%, while the measured data achieve 39.3% with the frequency from 47.2 to 70.3 GHz. Meanwhile, the simulated and measured 3 dB gain bandwidth of the proposed antenna are 52.86-66.86 (23.3%) and 51.86-67 GHz (25.5%), respectively. Peak gain increased by 3.37-5.57 dB when including the MS; providing 11.9-13.65 dBi for 57-66 GHz, corresponding to the WiGig bandwidth.

A wideband folded magnetoelectric dipole antenna with miniaturized integration for 5G applications

A 3-layer substrate integrated folded magnetoelectric dipole antenna is presented in this paper. The folded metal vias are proposed to broaden bandwidth and miniaturized antenna. Furthermore, the double-arc-edged patch, the single-arc-edged metal plane, side wall and removing shorted end are designed to improve the impedance matching and reduce the operating frequencies. The structure and parameters of the antenna are analyzed, especially the bandwidth blending and the current paths. A prototype was fabricated and measured. The presented antenna obtains a wide impedance bandwidth of 34.2% for VSWR≤2 from 4.88 to 6.89 GHz and a stable gain ranging from 6.0 to 7.5 dBi. Moreover, nearly identical unidirectional radiation patterns, low cross-polarization and low back radiation are achieved. The parameter of d s even can realize a lower operating frequency. The presented antenna is suitable for mass production with low cost by the printed circuit board technology, and promising for 5th Generation (5G) applications.

Efficient Procedure to Design Large Finite Array and Its Feeding Network With Examples of ME-Dipole Array and Microstrip Ridge Gap Waveguide Feed

An efficient procedure to design a large planar array and its corporate feeding network is presented. The procedure is verified by $8 \times8$ and $16\times16$ arrays of magnetoelectric dipoles (ME dipole) fed by microstrip ridge gap waveguide (MRGW) through a narrow slot. This procedure is based on using the frequency-dependent effective input impedance at the port of each element, which includes the effect of the mutual coupling between the antenna elements, which is used to design the corporate feeding network. In addition, the far-field characteristics of the array parameters such as directivity, gain, and the radiation patterns are predicted using the pattern multiplication method including the mutual coupling. The results are verified with the full-wave numerical solution. The procedure requires limited resources and speed up the design cycle. In the presented examples, the array elements are directly excited by the MRGW, which provides more flexibility to design complicated feeding networks and allow for distances between the elements less than a wavelength. Therefore, grating lobes are avoided. To accommodate such constraints, special designs of the power dividers are performed to provide the symmetric location of MRGW lines to avoid coupling between the feeding network lines. Furthermore, a transition from waveguide WR-15 to the MRGW is proposed to differential feed of the array antenna. The $16 \times 16$ array of ME dipoles has been fabricated. The measurement results show a 19% matching bandwidth ( $\vert \text{S}11\vert dB) and measured gain above 30 dBi with radiation efficiency better than 71%, all within a common bandwidth of 56–66 GHz.

A dual‐polarized antenna with low cross polarization, high gain, and isolation for the fifth‐generation array/multiple‐input multiple‐output communications

A dual-polarized antenna for the fifth-generation (5G) array/massive multiple-input multiple-output (MIMO) communications is proposed in this paper. Through combining dual-polarized differentially feeding structure and complementary magneto-electric (ME) dipole antenna, low cross polarization (X-pol), high gain, and isolation characteristics can be achieved by the antenna element. To take advantage of these characteristics in the array, a modified 1-to-16-way H-shaped differentially feeding network is designed to feed the 16-element antenna array. Here, vertical cross-shaped patches with dotted slots are arranged between adjacent ME-dipole antenna elements to further improve the array isolation. By removing the H-shaped differentially feeding network and the substrate at the bottom, a high-capacity MIMO antenna system can be achieved. Measured results show that low X-pol level of −35.7 dB and high gain of larger than 8.1 dBi can be attained by the antenna elements across the 5G frequency bands (3.3-5.1 GHz). In addition, the antenna array has exhibited high gain of 17.3 dBi and the MIMO antenna has realized very low envelope correlation coefficient of 0.004.

Bianisotropy for light trapping in all-dielectric metasurfaces

Magnetoelectric dipole coupling effects in all-dielectric metasurfaces composed of particles with bianisotropic electromagnetic response are investigated. This bianisotropic response is associated with the trapped mode excitation. Maintaining the trapped mode resonant conditions allows one to sufficiently increase the quality factor and reduce radiation losses in all-dielectric nanostructures (metasurfaces). An analytical model accounting for the contributions of both electric and magnetic dipole moments induced in particles by external electromagnetic fields is proposed. We show how bianisotropy can lead to the excitation of the trapped mode in metasurfaces. This mode corresponds to the electromagnetic coupling between the out-of-plane particle dipole moments, which do not radiate collectively from the metasurface plane resulting in the enhanced storage of electromagnetic energy. Our approach reveals a physical mechanism of the trapped mode excitation and demonstrates that the specially initiated bianisotropy of particles enables the energy flow between external electromagnetic waves and the trapped mode. Due to this bianisotropy, one can control the process of light-matter interaction and energy storage in all-dielectric metasurfaces via excitation of trapped modes.

A Planar Millimeter-Wave Antenna Array With a Pillbox-Distributed Network

This article introduces a new structure of radiating element for developing a wideband planar antenna array for millimeter-wave applications. The proposed radiating element consists of a slot-coupled magnetoelectric (ME) dipole and two microstrip patches, which produce the merits in bandwidth and gain enhancements for the antenna. The unique structure of the radiating element is an excellent candidate for building up an antenna array in millimeter-wave frequencies. To design the millimeter-wave antenna array with a low complexity in the power-distributed network, a stacked pillbox power divider is used to deliver equal-phase power distributions to all array elements. To provide sufficient bandwidth for the antenna array, an improved transition structured by a rectangular waveguide (WR) and a differential substrate-integrated waveguide (SIW) is adopted. To verify our proposed design, a prototype of the antenna array is examined and measured. The array obtains an impedance bandwidth of 30.7%, covering the frequency range from 53 to 72 GHz. Stable radiation patterns are found with the 3 dB gain bandwidth of 25.4% and the maximum gain of 25.1 dBi. This proposed antenna array can be employed to potential applications in millimeter-wave communication systems.

Developing Wideband Dual-Circularly Polarized Antenna With Simple Feeds Using Magnetoelectric Dipoles

A novel wideband magnetoelectric (ME) dipole antenna with dual circular polarization and unidirectional radiation is proposed in this letter. The proposed antenna is based on two perpendicular sub-ME dipoles realized by four V-shaped patches and four V-section columns, and each of them is composed of an electric dipole and a magnetic dipole in parallel. Fed by two simple Γ-shaped feeds, 90° phase difference between the electric dipole and the magnetic dipole in each of the sub-ME dipoles is achieved, hence the dual-circularly polarized radiation is generated. Wide impedance bandwidth is obtained in virtue of the two kinds of dipoles being excited simultaneously. The 3 dB axial-ratio (AR) bandwidth is enlarged by optimizing the V-section columns and a circular cavity. Besides, the port isolation is apparently enhanced by adding slits on the patches and elaborating different spacings between each feed and its two-sided columns. Measured results show that the proposed antenna has many appealing properties, such as a unidirectional radiation pattern, an impedance bandwidth (reflection coefficients ≤–10 dB and port isolation ≥ 10 dB) of 51.1% and a 3 dB AR bandwidth of 41.9%.