Search Results (45)

This paper presents two antenna array designs, an equal-phase array and a monopulse array, implemented using dielectric 3D-printing technology. To achieve wideband operation and low back-lobe radiation, a novel magneto-electric dipole (ME-dipole) element is first proposed. This element is derived from an open-ended waveguide; the open aperture functions as a magnetic dipole, while a pair of metallic patches placed at the aperture forms an electric dipole. Through structural evolution, the element is adapted for post-processing after 3D printing. The two arrays are then developed using this element. The equal-phase array employs a three-stage cascaded T-junction feeding network, whereas the monopulse array replaces the first-stage T-junction with a Magic-T coupler. The main bodies of both arrays are printed from dielectric material, and selected surfaces are copper-electroplated to form the necessary metallic components. The proposed arrays offer simple fabrication, low weight, and good performance. Measurements show that the equal-phase and monopulse arrays achieve overlapped bandwidths of 32.8% and 35.6% and peak gains of 13.1 and 13.5 dBi, respectively. The measured null depth of the monopulse array is below −32.3 dB. Full article

Conventional low-frequency antennas face a trade-off between miniaturization and radiation efficiency due to wavelength limitations. Although magnetoelectric (ME) antennas can overcome the electrical size constraint, existing designs lack structural tunability and performance enhancement. This paper proposes a Bézier curve-based (BCB) ME antenna that features a variable cross-section, introducing a shape tuning factor for precise geometric configuration. Using the lumped-mass method, the functional relationship between resonant frequency and the shape tuning factor is derived, establishing the theoretical basis for frequency tuning. A nonlinear multi-field coupled numerical simulation model is established for performance prediction. The BCB structure modifies internal stress distribution, enabling spatial reconstruction of magnetization modulation. The proposed design is validated by comparing the analytical model with our simulation results and literature-reported experimental data. Results show that the BCB design reduces resonant frequency and enhances converse ME (CME) coupling and far-field radiation without increasing material volume. Under clamped and free boundary conditions, the minimum resonant frequencies reach 7.2 kHz and 11.1 kHz, respectively, with CME coupling improved by 124% and 140%. When the shape tuning factor proposed in this work is set to 1/2, the proposed design degenerates into a traditional antenna with uniform cross-sections, which verifies the consistency of the established model. Full article

In this work, resonator applications based on the magnetoelectric coupling effect in multiferroic materials are systematically investigated, with particular emphasis on mechanically driven ME antennas. A finite-element model is established to analyze the electromechanical response and coupling behavior of the device. To better describe the converse ME process, a nonlinear magnetostrictive model is introduced to evaluate the influence of material properties, structural configuration, and DC bias magnetic field on resonance characteristics and radiation performance. The simulation results show that the radiation intensity of the ME antenna is strongly dependent on the applied bias magnetic field and can be significantly enhanced under the optimal operating condition. On this basis, key parameters are optimized to reduce the resonance frequency and improve the radiation response. Prototype devices are then fabricated and experimentally characterized. The measured results verify the predicted resonance behavior and demonstrate the feasibility of the proposed devices in low-frequency wireless communication and magnetic-anomaly sensing. This study provides theoretical guidance and experimental support for the design of portable low-frequency ME antenna systems and other resonator-based magnetoelectric devices. Full article

This study investigates an IPS-type Metglas/PMN-PT laminated magnetoelectric composite and its feasibility as a reciprocal mechanical magnetoelectric antenna for low-frequency transmission and reception. Finite-element simulations under quasi-static and frequency-domain conditions reveal strong magnetoelectric coupling under an optimal DC bias field, with both the direct magnetoelectric effect (DME) and converse magnetoelectric effect (CME) exhibiting pronounced resonance near 14.5 kHz, governed by the same longitudinal extensional vibration mode. Five IPS samples were fabricated and experimentally characterized. All devices showed resonant frequencies within 14.1–14.5 kHz, peak DME coefficients of 3.0 × 10⁶ to 3.9 × 10⁶ pC/Oe, and peak CME coefficients of 12.0~15.8 Oe·cm/V, confirming good fabrication consistency, transmit–receive reciprocity, and array-integration potential. The parallel IPS antenna generated a magnetic flux density of 37 nT at 1 m, and exhibited an equivalent magnetic noise of 63 fT/Hz^1/2 at 14.45 kHz. These results demonstrate that the proposed IPS structure combines high-sensitivity reception with efficient low-frequency transmission, showing strong potential for miniaturized, low-power, and long-range magnetic communication and underwater communication applications. Full article

Continuous introduction of advanced optimization algorithms promotes the development of electromagnetic (EM) technology in radar and communication systems. Wideband antenna design within a given space and wideband array pattern synthesis, especially in the scenario of strong mutual coupling, are two typical challenging electromagnetic problems. In this paper, a nature-inspired algorithm, i.e., the water cycle algorithm (WCA), is introduced to resolve the above two EM problems. Two typical wideband antennas, i.e., the dual-band E-shaped microstrip antenna and the typical magnetoelectric (ME) dipole antenna, are designed on the basis of the established WCA-based antenna design scheme. Compared with the well-known algorithms that have been introduced in antenna design, including the differential evolution (DE) algorithm and the gray wolf optimizer (GWO), better results can be achieved with WCA. In the sequel, a WCA-based low peak sidelobe level (PSLL) pattern synthesis is implemented based on a uniformly spaced 27-element folded fractal ME dipole array antenna with mutual coupling as high as −10 dB, the results of which further validate the superiority of WCA in array pattern synthesis and demonstrate the value of this application innovation. Full article

Following the persistent evolution of terrestrial 5G wireless systems, a new field of underwater communication has emerged for various related applications like environmental monitoring, underwater mining, and marine research. However, establishing reliable high-speed underwater networks remains notoriously difficult due to the severe RF attenuation in conductive seawater, which strictly limits range coverage. In this article, we focus on a comprehensive review of different antenna types for future underwater communication and sensing systems, evaluating their performance and suitability for Autonomous Underwater Vehicles (AUVs). We critically examine and compare distinct antenna technologies, including Magnetic Induction (MI) coils, electrically short dipoles, wideband traveling wave antennas, printed planar antennas, and novel magnetoelectric (ME) resonators. Specifically, these antennas are compared in terms of physical footprint, operating frequency, bandwidth, and realized gain, revealing the trade-offs between miniaturization and radiation efficiency. Our analysis aims to identify the benefits and weaknesses of the different antenna types while emphasizing the necessity of innovative antenna designs to overcome the fundamental propagation limits of the underwater channel. Full article

This paper presents a compact magneto-electric dipole (MED) antenna optimized for wideband circularly polarized (CP) radiation for 5G applications. It incorporates a staircase-shaped electric dipole with trimmed corners to excite orthogonal modes for enhanced CP performance. The proposed single-layer MED antenna achieves a $20.6\%$ wide-impedance bandwidth ($|S_{11}| <-10$ dB, $22.97$–$28.12$ GHz) and $21.9\%$ CP bandwidth ($AR<3$ dB, $22.23$–$27.83$ GHz) with a compact footprint of $15\times 15\times 1.6{\mathrm{mm}}^3$. There is a symmetrical radiation pattern with a co-to-cross polarization ratio $>23$ dB and a stable gain of $8.8$ dBi. An equivalent circuit model is optimized via particle swarm optimization (PSO). The optimized MED antenna is utilized to investigate various CP-MIMO configurations and wideband sequential arrays. Next, a $1\times 2$ CP-MIMO antenna system is developed, employing polarization diversity in parallel and mirror configurations. Isolation is improved by etching a ground slot between the MED elements, yielding isolation levels of below $-20$ dB and $-23$ dB, respectively. Further, a $2\times 2$ CP-MIMO configuration is designed and evaluated. This arrangement demonstrates an envelope correlation coefficient (ECC) of $1\times {10}^{-3}$ and a diversity gain of approximately 10 dB across the operating bandwidth. Finally, a sequential array is designed that applies a ${90}^{\circ }$ sequential rotation and phase excitation to MED elements for high-gain CP 5G communications. Here, various array sizes are evaluated, with an $8\times 8$ MED array providing CP radiation ($AR\le 1$ dB) from 20 to 30 GHz with enhanced impedance and axial ratio bandwidths and stable gain with a peak value of $27.47$ dBi. Full article

This paper presents a dual-polarized millimeter-wave filtering antenna based on a broadband partially reflective surface lens for gain improvement. It consists of a magneto-electric dipole (M-E dipole) as the source and a partially reflective surface (PRS) as the lens. The M-E dipole source antenna employs a dual-layer substrate structure, and its working principle is investigated by the circuit analysis method. A stub-loaded transmission line network is used to study the radiation characteristics of the source antenna, and the simulation results reveal that it has intrinsic integrated bandpass-type filtering response. The PRS lens is realized by designing a square high permittivity superstrate. By combining the source antenna and the lens, a wideband dual-polarized high gain cavity antenna is developed. The fabricated prototype has a measured impedance bandwidth of 33.3% (25–35 GHz), and a maximum in-band gain of 12.3 dBi. Above features make the proposed antenna a good candidate for 5G millimeter-wave sensor applications. Full article

In this study, we propose a novel wideband aperture-coupled magneto-electric (ME) dipole antenna that achieves enhanced bandwidth by simultaneously leveraging ME resonance and aperture-coupled excitation. Building upon the conventional ME dipole architecture, the antenna integrates a pair of horizontal metal patches forming the electric dipole and a pair of vertical metal patches forming the magnetic dipole. A key innovation is the aperture-coupled feeding mechanism, where electromagnetic energy is transferred from a tapered microstrip line to the dipole structure through a slot etched in the ground plane. This design not only excites the characteristic ME resonances effectively but also significantly improves impedance matching, delivering a markedly broader impedance bandwidth. To validate the proposed concept, a prototype antenna was fabricated and experimentally characterized. Measurements show an impedance bandwidth of 84.48% (3.61–8.89 GHz) for $S_{11}$ ≤ −10 dB and a maximum in-band gain of 7.88 dBi. The antenna also maintains a stable, unidirectional radiation pattern across the operating band, confirming its potential for wideband applications such as 5G wireless communications. Full article

This paper presents a symmetry-driven broadband circularly polarized magnetoelectric dipole antenna with bandpass filtering response, where the principle of symmetry is strategically employed to enhance both radiation and filtering performance. The antenna’s circular polarization is achieved through a symmetrical arrangement of two orthogonally placed metallic ME dipoles combined with a phase delay line, creating balanced current distributions for optimal CP characteristics. The design further incorporates symmetrical parasitic elements—a pair of identical inverted L-shaped metallic structures placed perpendicular to the ground plane at −45° relative to the ME dipoles—which introduce an additional CP resonance through their mirror-symmetric configuration, thereby significantly broadening the axial ratio bandwidth. The filtering functionality is realized through a combination of symmetrical modifications: grid slots etched in the metallic ground plane and an open-circuited stub loaded on the microstrip feed line work in tandem to create two radiation nulls in the upper stopband, while the inherent symmetrical properties of the ME dipoles naturally produce a radiation null in the lower stopband. This comprehensive symmetry-based approach results in a well-balanced bandpass filtering response across a wide operating bandwidth. Experimental validation through prototype measurement confirms the effectiveness of the symmetric design with compact dimensions of 0.96${\lambda }_0$ × 0.55${\lambda }_0$ × 0.17${\lambda }_0$ (${\lambda }_0$ is the wavelength at the lowest operating frequency), demonstrating an impedance bandwidth of 66.4% (2.87–5.05 GHz), an AR bandwidth of 31.9% (3.32–4.58 GHz), an average passband gain of 5.5 dBi, and out-of-band suppression levels of 11.5 dB and 26.8 dB at the lower and upper stopbands, respectively, along with good filtering performance characterized by a gain-suppression index (GSI) of 0.93 and radiation skirt index (RSI) of 0.58. The proposed antenna is suitable for satellite communication terminals requiring wide AR bandwidth and strong interference rejection in L/S-bands. Full article

This work presents a novel dual-polarized antenna array tailored for Internet of Things (IoT) applications, specifically designed to operate in the millimeter-wave (mm-wave) spectrum within the frequency range of 30–60 GHz. Leveraging printed ridge gap waveguide (PRGW) technology, the antenna ensures robust performance by eliminating parasitic radiation from the feed network, thus significantly enhancing the reliability and efficiency required by IoT communication systems, particularly for smart cities, autonomous vehicles, and high-speed sensor networks. The proposed antenna achieves superior radiation characteristics through a cross-shaped magneto-electric (ME) dipole backed by an artificial magnetic conductor (AMC) cavity and electromagnetic bandgap (EBG) structures. These features suppress surface waves, reduce edge diffraction, and minimize back-lobe emissions, enabling stable, high-quality IoT connectivity. The antenna demonstrates a wide impedance bandwidth of 24% centered at 30 GHz and exceptional isolation exceeding 40 dB, ensuring interference-free dual-polarized operation crucial for densely populated IoT environments. Fabrication and testing validate the design, consistently achieving a gain of approximately 13.88 dBi across the operational bandwidth. The antenna’s performance effectively addresses the critical requirements of emerging IoT systems, including ultra-high data throughput, reduced latency, and robust wireless connectivity, essential for real-time applications such as healthcare monitoring, vehicular communication, and smart infrastructure. Full article

A high-gain circularly polarized (CP) magnetoelectric dipole (ME-dipole) radiating element is demonstrated at a millimeter-wave (MMW) 5G band of 37–43.5 GHz. Each ME-dipole radiating element, consisting of two pairs of ring-shaped and L-shaped metal posts is excited by a cross-shaped substrate-integrated waveguide (SIW) coupling slot to achieve CP radiation. Through the use of all-metal radiating structures with a height of 3.4 mm, high-gain and high-efficiency radiation performances are achieved. For proof of concept, a 4 × 4 antenna array with a SIW feeding network is designed, fabricated, and measured. The measured impedance bandwidth of the proposed 4 × 4 CP antenna array is 19.2% from 33.9 to 41.1 GHz for |S11| ≤ −10 dB. The measured 3 db AR bandwidth is 10.3% from 37 to 41 GHz. The measured peak gain is 20.3 dBic at 41 GHz. The measured and simulated results are in good agreement. Full article

This article presents a novel, compact, and flexible dual-band magnetoelectric dipole rectenna designed for radio frequency (RF) energy harvesting. The rectenna consists of a unique antenna structure, combining electric and magnetic dipoles to create unidirectional radiation patterns, minimizing interference from the human body. The rectifier is integrated with the antenna through conjugate matching, eliminating the need for additional matching circuits, reducing circuit losses, minimizing design complexity, and improving conversion efficiency. The proposed rectenna utilizes a flexible graphene film as the radiating element, which offers excellent conductivity and corrosion resistance, enabling conformal operation in diverse scenarios. Simulation and experimental results show that the rectenna operates effectively at 3.5 GHz and 4.9 GHz, achieving peak conversion efficiencies of 53.43% and 43.95%, respectively, at an input power of 4 dBm. The simulated and measured results achieved good agreement. The rectenna maintains stable performance under various bending conditions, demonstrating its suitability for flexible, wearable RF energy-harvesting systems. Full article

Magneto-electric dipole (ME-dipole) antennas offer several advantages, including wide impedance bandwidth, stable high gain, unidirectional radiation, and low back-lobe radiation patterns, making them suitable for modern wireless communication systems. However, the thickness of conventional ME-dipole antennas is typically about a quarter wavelength (0.25${\lambda }_o$) at the center operating frequency, which may not be desirable for portable device applications. This work introduces a new feeding method that reduces the antenna profile and ground plane size while maintaining the same advantages. A suspended horizontal line is proposed to excite the cavity-less ME-dipole antenna through proximity coupling. The measured results demonstrate a wide impedance bandwidth of 45.3% (ranging from 2.05 GHz to 3.25 GHz) and an average in-band gain of 9 dBi with stable $\pm 1$ dBi in-band variation with a ground reflector of size about 0.89${\lambda }_o^2$. More importantly, the cavity-less design reduces the overall thickness of the antenna to 0.17${\lambda }_o$ at the center operating frequency. Full article

This paper presents a high-performance circularly polarized (CP) magneto-electric (ME) dipole antenna optimized for wideband millimeter-wave (mm-wave) frequencies, specifically targeting advancements in 5G and 6G technologies. The CP antenna is excited through a transverse slot in a printed ridge gap waveguide (PRGW), which operates in a quasi-transverse electromagnetic (Q-TEM) mode. Fabricated on Rogers RT 3003 substrate, selected for its low-loss and cost-effective properties at high frequencies, the design significantly enhances both impedance and axial ratio (AR) bandwidths. The antenna achieves an impressive impedance bandwidth of 31% (25.24–34.50 GHz) and an AR bandwidth of 24.9% (26.40–33.91 GHz), with a peak gain of up to 8.4 dBic, demonstrating a high cross-polarization level. The experimental results validate the high-performance characteristics of the antenna, making it a robust candidate for next-generation wireless communication systems requiring CP capabilities. Full article