Dongping Su

Metasurface arrays can achieve beam control at low cost and high quality by providing different phase compensations for each unit, effectively focusing microwave energy on target locations. With the development of short‐range communication technology or microwave power transmission technology, the demand for focusing has also increased. Using metasurface arrays to achieve multi‐target focusing has wide application value. However, as the number of focal points increases, the superposition of electromagnetic wave propagation paths leads to significant interference phenomena, which can impact potential applications. Existing solutions are unable to solve such complex problems involving a large number of targets with conflicts between them. Multi‐objective algorithms, by iteratively obtaining a set of optimal solutions, provide decision support for designers in complex multi‐objective problems. This paper alters the phase of cells in a reflective array, calculates the near‐field electric field model using the Fresnel diffraction formula, and employs various solutions using the Non‐dominated Sorting Genetic Algorithm III (NSGA‐III) combined with different constraints. Finally, we select the balanced solution to establish the array. After simulation, three adjacent focal points with normalized central values of 1, 0.86, and 0.88 were obtained, with the maximum electric field value outside the focal points being only 0.58, demonstrating the feasibility of multi‐objective algorithms in solving complex multi‐focal problems.

In this paper, a metasurface antenna (MA) is designed for quasi nondiffraction beam size adjustment and microwave power transmission. A phase calculation expression is derived to generate different spot sizes of generated quasi nondiffraction beams. The result shows the metasurface antenna can make the electric field decay slower and apply to various polarization situations. At the same time, the measured result demonstrates that we can adjust the size of the beam by setting the parameters ( d ) of the derived expression. As for the microwave power transmission, the proposed MA can deliver energy further, and the maximum harvested power by the receiver can up to more than 13 times as much as without metasurface condition when the transmission power is 0 dBm.

We present a novel phase modulation method for generating two-dimensional Airy vortex beams carrying orbital angular momentum (OAM) modes in microwave bands. This approach enhances the focal field intensity of the non-diffracting Airy OAM beam while simultaneously suppressing divergence at a longer distance without compromising its nondiffractive property. By leveraging Fourier optics theory, we theoretically analyze the propagation behavior of EM waves and outline a detailed design procedure. To achieve superior performance, a dual-polarized metal-only Huygens metasurface is designed at 5.8 GHz, synthesizing the full range of impedances required to attain 360-degree phase coverage and high transmission amplitude (-2 dB). To demonstrate the feasibility of our approach, we fabricate an experimental prototype using laser engraving, a cost-effective technique suitable for extreme environments. Full-wave simulations and experimental measurements are conducted to validate the design and its performance.

We propose a multi-feed Huygens’ metasurface (HMS) transmitarray designed for microwave power transmission applications. A near-field distributed optimization mechanism is employed to determine the optimal focal lengths of subarrays. We aim to balance between illumination efficiency and interference from incident waves, leveraging the conjugate field matching method for precise phase compensation. This approach ensures robust radiation performance, notably reducing the focus-to-diameter ratio for large-aperture antenna arrays. Consequently, it mitigates spatial dispersion effects and upholds the operational bandwidth of mega antennas. As a proof of concept, we have designed a single-layer HMS transmitarray measuring 1.14 × 1.14 m2 (22 λ at 5.8 GHz). Through simulation, we have attained a peak gain of 35.47 dB and an aperture efficiency of 57.73%. Our design exhibits outstanding radiation performance, combined with advantages, such as a low profile, cost-effectiveness, and scalability.

In this paper, a phase expression is derived to calculate the compensation phase of each point on the metasurface (MS), which is then used to generate a focused beam with different elevation (θ) and azimuth (φ) angles. The simulation results show that the expression can achieve both 1D and 2D focused beam scanning. An MS with an expected beam direction of θ and φ both equal to 45∘ is fabricated using the derived phase expression and a designed phase control unit. The final measurement results indicate that the beam can be generated with minimal error in the desired direction. Furthermore, due to the focusing effect of the MS, more power is concentrated in the direction of beam propagation. When compared with the system without the MS, the harvested power by the receiver can be improved by at least 39.0% (η>39.0%) across all measured ranges, with a peak value of η reaching 53.0% when the system incorporates the proposed MS. This means that the designed MS can adjust the direction of the generated beam while concentrating power on the beam propagation path. The method proposed in this paper can be applied to the moving target power transmission application.

In this paper, an impedance-matching voltage regulator (IMVR) for high-power rectifier in microwave wireless power transmission (MWPT) is analyzed and fabricated, which is designed based on Zeta converter and Linear voltage regulator (LDO). System-level verification shows the proposed novel IMVR has potential application value for high-power MWPT system. Measurement results show that this design scheme realizes larger load range of constant voltage output and higher RF-DC power conversion efficiency (PCE) while improving the applicability and practicability of microwave rectifier. With an input power of 37 dBm, the maximum conversion efficiency of the rectifier with IMVR can reach up to 57.41%. Besides, with an input power of 38 dBm, the highest output DC power can reach up to 3.4 W, meeting the rated power of most small electronics. Compared with other similar schemes, the proposed rectifier with IMVR presents higher overall efficiency and adjustable regulated output 5 V / 12 V / 24 V. The IMVR can overcome the impedance sensitivity of the rectifier and realize the output of stable DC voltage required by most electronics.

We propose a method for directly constructing three-dimensional (3-D) accelerating beams with twisted wavefront amplitude and phase profiles in real space. The design strategy combines the optical caustic method with antenna array theory to synthesize the required phase distribution over the transmitting aperture. The constructed beam is further enhanced by translating and superimposing the desired beam trajectory. The dynamics of the resulting helical beam are analyzed using Fresnel diffraction theory through a fast Fourier transform (FFT), revealing the uniform clustering of localized electromagnetic waves along the predefined curved trajectory in free space. Moreover, we demonstrate the generation of an antisymmetric double helical beam with distinct amplitude and phase characteristics. As an implementation example, we design a high transmittance (−0.9 dB) large-aperture Huygens’ metasurface (HMS) comprising 2307 miniaturized elements ( $0.37\lambda$ ) on a single-layer ultrathin ( $0.02\lambda$ ) dielectric substrate. Full-wave simulations are conducted to validate the feasibility of our design concept. This approach offers potential applications in near-field scenarios, including microwave power transmission, imaging, and biomedical fields.

A dual-layer metal-only Huygens' unit is presented, which consists of double anti-symmetric multi-slot structures without relying on expensive dielectric substrates to achieve a complete 360° phase and high transmission amplitude (-2 dB). Also, the design strategy incorporates extra magnetic resonance, enriches the Huygens resonance, and allows more degrees of freedom to exploit the second-harmonic for center frequency multiplication. In order to verify the design scheme, an 18×18 transmitarray prototype is created by laser engraving, which consists of two thin metal sheets with a length of 360 mm. The measurement results show a maximum gain of 25 dB, an aperture efficiency of 51.9%, and a 3-dB bandwidth of 10.1%. As a proof of concept, another frequency multiplication design is verified through full-wave simulations to achieve a maximum gain of 26.2 dB at 11.9 GHz under the illumination of a standard pyramid horn with a center frequency of 5.8 GHz.