Wideband Magneto-electric Dipole Research Articles

Impact of dielectric substrate on the performance of an 8 × 8 magneto-electric dipole phased array antenna for 5G mmWave applications

The impact of the substrate dielectric material on the performance of a wideband magneto-electric dipole (MED) phased array antenna is systematically studied in this article. Four commercially available dielectric substrates for mmWave applications, i.e., Rogers RO 5880, RO 3003, RO 4350B, and Panasonic Megtron-6, are considered in the design investigation of the proposed MED phased array antenna. First, the influence of the dielectric constant on the operating frequency of the unit cell MED antenna is explored in the broadside direction (θ = 0°). Second, the scanning impedance is assessed at various scanning angles for both E- and H-plane scanning. Finally, the radiation performance of the proposed design of a finite 8 × 8 MED phased array antenna is examined. This study gives a foundational understanding of the impact of dielectric characteristics on the performance of MED phased arrays. The analysis revealed that the MED phased array antenna based on substrates with a higher dielectric constant exhibited a smaller scanning angle than the substrate with a lower dielectric constant. The findings may serve as practical guidelines for selecting the dielectric substrates for the 5G mmWave phased array antenna in order to adapt their design to an application’s specifications.

Miniaturization of a wideband magnetoelectric dipole antenna by folding

AbstractIn this Letter, we investigate a wideband magnetoelectric dipole antenna miniaturized by folding. In the proposed design, a folded L‐shaped electric dipole is used instead of the conventional half‐wavelength horizontal electric dipole, and a pair of vertically folded shorted patches act as a magnetic dipole, producing a miniaturized radiator. Furthermore, a small‐size U‐shaped reflector replaces the traditional large‐size planar reflector, resulting in a decrease in the low end of the frequency band, while the high end of the frequency band remains almost unchanged. A better impedance matching is also obtained over the entire operating frequency band. Ultimately, a miniaturized overall structure and a wide bandwidth are obtained simultaneously. The overall size of the proposed antenna is only (where is the longest operating wavelength), which is 82% smaller than the size of the original design, but the proposed antenna can still obtain a large bandwidth of 120% (1–4 GHz) for VSWR < 2. Furthermore, stable radiation patterns are realized with an average gain of 5 dBi within the operating frequency band.

Design of a Low-Profile Wideband Magnetoelectric Dipole Antenna with Reduced Gain Drop

In this paper, a novel low-profile magnetoelectric (ME) dipole antenna with wideband is presented. The conventional vertical fixing structure is bended four times from the center to the sides. The Γ-shaped feeding structure is bended two times to lower the height of the antenna step by step. The effect of three kinds of vertical wall is discussed to show their influence on boresight gain. Through comparison, only one vertical wall is erected on the left side of the ground to decrease the boresight gain drop at 2.2 GHz. Both simulation and analysis are made to sufficiently explain the working principle. At last, the proposed ME dipole antenna has only 0.095λ0 (λ0 is the center operating wavelength in free space) in height, and the wideband property is still maintained. By simulation, the relative bandwidth for VSWR < 2.0 is 47.9% (from 1.35 to 2.2 GHz). The boresight gain ranges from 8.1 to 9.6 dBi in the operating band. The measured relative bandwidth for VSWR < 2.0 is 50.3% (from 1.34 to 2.24 GHz), and the boresight gain ranges from 7.38 to 8.73 dBi. The gain drop on boresight is less than 1.4 dBi. Radiation patterns show a unidirectional characteristic in the whole operating band. Additionally, the cross-polarization level is less than −25 dB on boresight. The simulating and measuring results agree well with each other. Therefore, the proposed antenna is suitable for applications of limited height and wideband.

60 GHz dual‐polarized magneto‐electric dipole antenna array with hybrid gap waveguide feeding network in low temperature co‐fired ceramic technology

AbstractA 60 GHz 8 × 8 dual‐polarized aperture‐coupled magneto‐electric (ME) dipole antenna array in low temperature co‐fired ceramic (LTCC) technology is proposed. Taking advantage of the LTCC technology of high integration, the antenna array is composed of three parts, including the wideband ME dipole elements, dual‐polarized strip‐line series feeding network and low‐loss gap waveguide (GWG) feeding network. The ME dipole antenna element is fed by aperture coupling with 45° rotation. Two separate orthogonal strip lines are located right below the aperture to realize dual polarization performance. The simulated −10 dB impedance bandwidth of the dual‐polarized antenna element is 50–66.5 GHz with an isolation lower than −20 dB for two input ports. By employing the proposed radiating element, a 4 × 4 wide‐band dual‐polarized antenna subarray is realized by using strip‐line series‐feed technology. A compact hybrid low‐loss feeding network is realized by combing the GWG technology with the strip‐line series feed technology. For demonstration, one prototype was fabricated. The measured impedance bandwidth is 14.2% and 16.7% respectively for dual polarizations with |S11| < −8 dB, and the port isolation is lower than −20 dB over the entire frequency band of interest.

Design and measurement of a novel metal‐only wideband magneto‐electric dipole antenna using asymmetrical structure

A novel metal-only wideband magneto-electric dipole antenna is designed and measured in this letter. The antenna consists of two rectangular patches etched with asymmetrical slots as electric dipole, two folded patches as magneto-dipole, trident-shaped feeding structure and side-slotted ground, large metallic ground. The electric dipole is horizontally placed on both sides of the feeding structure, and two folded patches are assembled vertically on the small ground. Two symmetrically sided slots are etched on the small ground to reduce the profile and a trident-shaped feeding strip is employed to widen the bandwidth, while a lower ground with a large size is designed to suppress the radiation in the backward direction. Finally, the antenna prototype is fabricated and measured. The measured results show that −10 dB impedance bandwidth is achieved up to 75.9% at 2.7 GHz from 2.0 to 4.1 GHz. At 2.7 GHz, the measured peak gain is 9.0 dBi.

The Grey Wolf Optimizer and Its Applications in Electromagnetics

The grey wolf optimizer (GWO) is a newly developed swarm intelligence-based optimization technique that mimics the social hierarchy and group hunting behavior of grey wolves in nature. Here, a detailed introduction of the GWO algorithm is given, after which, three sets of examples are investigated: first, numerical experiments on four benchmark functions are conducted; second, the GWO is applied to the synthesis of linear arrays with the aim of reducing the peak sidelobe level under various constraints; and finally, the performance of the GWO is further verified on the optimization design of two representative antennas, namely, a dual-band E-shaped patch antenna and a wideband magneto-electric dipole antenna. The results show that the GWO is capable of outperforming or providing very competitive results compared with some well-known metaheuristics such as the genetic algorithm, particle swarm optimization, and differential evolution. Thus, it may serve as a promising candidate for handling electromagnetic problems.

A circularly polarized wide-band magneto-electric dipole antenna with simple structure for BTS applications

A circularly polarized magneto-electric dipole antenna with wide frequency band for base transceiver station (BTS) is presented. The structure of the proposed antenna is composed of a cavity metallic reflector with defected side walls, two pairs of vertical and trapezoidal horizontal copper plates and a Г-shaped feed line. Defected side walls of the metallic reflector are utilized to improve the gain, front to back ratio (FBR) and impedance matching. Electric dipole and quasi magnetic dipole are realized with horizontal plates and shorted vertical plates, respectively. The trapezoidal horizontal plates are employed to obtain circular polarization (CP) characteristic with 3-dB axial ratio bandwidth of 41% from 1.7 to 2.6 GHz. Experimental results show that the proposed antenna operates at frequency range of 1.4–2.8 GHz with S11 < −10 dB and 3-dB axial ratio of 1.8 dB and 2.1 dB for frequencies 1.9 GHz and 2.1 GHz, respectively. Furthermore, half-power beamwidth (HPBW) wider than 60.5° and the gain higher than 6.2 dBi are realized.

Wideband circularly polarized magnetoelectric dipole antenna with I-slot for C-band applications

This paper presents a circularly polarized wideband magnetoelectric dipole antenna with a defective semicircular patch for C-band applications (4–8 GHz). In the proposed design, in order to get proper impedance matching and stable gain, a pair of folded vertical patches is shorted between a pair of defective semicircular patches and minimum ground plane. The defective semicircular patches work as an electric dipole, while the vertical patches work as a magnetic dipole. The Γ-shaped single-feed structure is used to excite both dipoles together to achieve symmetrical radiation patterns. Minimum ground and the folded structure maintain the low profile of the presented design. The circular polarization is obtained by incorporating I-shaped slots in semicircular patches, extending to the lower and upper sides of the curved edges symmetrically on the both sides. A prototype was manufactured and the measured results agreed well with the simulated results. The results show an impedance bandwidth of 60.37% (S11 < − 10 dB) from 3.71 to 6.91 GHz, 3-dB axial ratio bandwidth of 20.60% from 3.71 to 4.55 GHz and a broadside stable gain of 6 ± 0.5 dBic. The antenna also shows good radiation efficiency of around 80% over the entire operating range. Therefore, the proposed antenna can be used in 5G Wi-Fi (5.15–5.875 GHz) wireless communication systems and several C-band applications.

A novel uniplanar wideband magneto-electric dipole antenna element

A novel uniplanar wideband magneto-electric dipole antenna element is proposed in this paper. The proposed antenna is composed of the conventional bow-tie radiation patch as an electric dipole, a semi-circular loop, which works as a magnetic dipole, a coplanar ground plane, two directors with different lengths for enhancing gain, and a microstrip-to-coplanar stripline transition balun. The designed antenna adopts a small-size coplanar ground plane to achieve a uniplanar structure. Consequently, this method reduces the space size immensely and makes the antenna suitable for the array application. In addition, a tapered slot structure is utilized to improve impedance matching. The prototype of the proposed antenna was fabricated and measured. The measured results keep in good accordance with the simulated ones. The simulated results show that the proposed antenna obtains a broad impedance bandwidth of 60.5% from 2.25 to 4.20 GHz (voltage standing wave ratio [VSWR] ≤ 2) which can be applied for wireless local area network (WLAN) (2.4–2.484 GHz), worldwide interoperability for microwave access (WiMAX) (2.5–2.69/3.4–3.69 GHz), and long term evolution (LTE) (2.5–2.69 GHz). Meanwhile, the stable gain, low cross-polarization, stable unidirectional radiation patterns, and low back lobe are obtained within the operating frequency band. The array composed of the proposed antenna elements is also investigated in this paper.

A Novel Wideband Magneto-Electric Dipole Antenna with Improved Feeding Structure

A novel feeding structure in magneto-electric dipole antenna is proposed and analyzed, which is simpler and better in performance than previous designs, involving differential feeding. Due to this improved feeding structure, the antenna has achieved an impedance bandwidth of 133.3% ( 0.5 GHz – 2.5 GHz, resulting into an ultra-wide band antenna. The maximum broadside gain 7.5dBi with unidirectional radiation pattern has also been reported for the entire the range of operation. Symmetry in E-plane and H-plane radiation patterns has been observed due to the symmetry in structure and excitation of antenna. The antenna has also been able to achieve cross polarization levels.

Wideband Magneto-Electric Dipole Antenna for 60-GHz Millimeter-Wave Communications

A new wideband magneto-electric dipole antenna is proposed for 60-GHz millimeter-wave applications. This antenna features wideband and stable gain characteristics. The low cross polarization and low back radiation are obtained owing to its complementary antenna structure. The prototype of the single element was built using the low-cost single-layer printed circuit board (PCB) technology. The proposed antenna exhibits an impedance bandwidth of 51% (SWR ≤ 2) and a gain of approximately 8 dBi.

A WIDEBAND MAGNETO-ELECTRIC DIPOLE ANTENNA USING CPW STRUCTURE

A new wideband magneto-electric dipole antenna using coplanar waveguide (CPW) structure is proposed in this paper. The proposed antenna consists of a pair of horizontal triangular patches and two vertically oriented L-shaped strips. By introducing triangular patches working as an electric dipole, the antenna can operate in a wide band. With the use of L-shaped strips equivalent to a magnetic dipole, the antenna is low in proflle. A microstrip feed line is located between the two L-shaped strips to form a coplanar waveguide structure and excite the antenna. By carefully adjusting the gap between the feed line and the strips, the impedance bandwidth can be improved largely. A parametric study is performed to provide information for designing and optimizing such an antenna. A prototype is fabricated and measured. The simulated and measured results show that the impedance bandwidth for SWR less than 2 of the proposed antenna is 58.7% (1.95{3.57GHz). Due to the complementary nature of the antenna, the proposed antenna has a unidirectional radiation pattern with low-polarization and low back-lobe radiation over the whole operating band. Furthermore, the gain of the antenna is stable across the entire bandwidth.

A Wideband Magneto-Electric Dipole Antenna

A new wideband magneto-electric dipole antenna composed of a horizontal bowtie electric dipole and a vertically oriented folded shorted patch antenna is designed. The antenna is excited by a stair-shaped probe feed without the need of an additional balun. A prototype was fabricated and measured. Results show that an impedance bandwidth of 95.2%, with ${\rm SWR}\leq 2$ from 1.65 GHz to 4.65 GHz, was achieved. Stable radiation pattern with low cross polarization, low back radiation, nearly identical E- and H-plane patterns and an antenna gain of 7.9 $\pm$ 0.9 dBi was found over the operating frequencies.