This paper proposes a hybrid microwave power receiving (MPR) metasurface array with efficient dual matching of surface impedance and phase gradient. The hybrid array comprises three components: a reflective phase gradient metasurface (R-PGM) array, a surface wave focusing array, and an energy harvesting port. The R-PGMs efficiently convert incident electromagnetic waves into surface waves. The surface wave focusing array then concentrates the energy onto the integrated harvesting port through dual matching of surface impedance and phase gradient. Connecting a rectifier circuit enables efficient microwave energy reception and RF-DC conversion, avoiding the need for multiple rectifiers or complex feeding networks in traditional MPR designs. Numerical analysis and experimental tests verify the superior performance of this hybrid array design in efficient microwave energy harvesting and RF-DC conversion, achieving 90.84% plane wave-to-surface wave conversion efficiency, 76.67% surface wave energy harvesting efficiency, and 49.28% overall RF-DC conversion efficiency. Across the wideband range of 5.6–6.0 GHz, the energy harvesting efficiency remains consistently high, demonstrating the superior characteristics and promising potential of this design in MPR device development.

In this letter, a broadband and wide-angle linear-to-circular polarization converter (LCPC) based on three-layer transmissive metasurface is proposed, to solve the problem of efficiency degradation caused by polarization mismatch in mobile microwave wireless power transmission (MWPT). The simulated results show that our proposed model has an axial ratio (AR) of less than 3 dB in the 4.24-6.24 GHz band (38.17% bandwidth) with a maximum insertion loss (IL) of 1.66 dB for normal incidence in both yz and xz plane. In addition, 50° incidence angle stability can also be achieved. To verify the feasibility, a sample with a total dimension of 300×300×5.105 mm ³ is fabricated. The measured results demonstrate that our LCPC combines the advantages of broadband, wide-angle, low-loss and low-profile. With this LCPC, the received power is verified to remain stable when the polarization angle of the receiving antenna changes.

As a major space-based energy infrastructure in respond to the challenge of climate change, Space Solar Power (SSP) has attracted extensive international attention for more than 55 years. Recently, various SSP concepts have been proposed, aiming to efficiently harvest Giga-Watts of solar power over Earth's geostationary orbit (GEO) and transmit it to Earth wirelessly. Based on the Multi-Rotary joints Solar Power Satellite (MR-SPS) concept proposed in 2014, this paper presents an updated Modular MR-SPS (MMR-SPS) concept, together with the challenges and design considerations. The primary objective is to address the challenges associated with long-distance DC electric power transmission and exceptionally high-precision microwave power transmission (MPT). The MMR-SPS employs multiple modules, each further including a solar sub-panel and an antenna sub-panel. The solar sub-panel and antenna sub-panel in each module are connected with each other via conductive rotary joints with a much shorter distance compared with that in the MR-SPS concept. As a result, lower voltage in electric power transmission is allowed, which significantly reduces the complexity of the system and increases its reliability. Retro-reflective beamforming is employed to ensure the accurate steering of the microwave power beam to the ground's receiving aperture. For the first time, this paper analyzes and validates the performance of using retro-reflective beamforming to compensate for antenna position deviations through a numerical calculation model that includes near-field effects. Additionally, the paper outlines the transportation and assembly methods, along with the considerations of the full life-cycle cost for an MMR-SPS.

Microwave wireless power transmission (MWPT) over long distances holds the significant value and broad application prospects. The current studies mainly target fixed objects, but few focus on moving targets like drones. Technical challenges in MWPT for moving targets lie in meeting the real-time and accuracy requirements of beam pointing control, while also meeting the quality requirements of the radiation pattern when moving targets are in different positions. To address these performance requirements, this paper proposes a fast beam pointing control method based on the deep learning model. Specifically, the ResNet-18 framework is improved as the core to construct the mapping relationship between the positions of moving target within the effective power transmission region and the feeding amplitudes and phases of the phased array antenna. To improve the accuracy of the antenna pattern synthesis, the Eigen-driven analysis method (EDM) is proposed, in which the coupling effects among the array elements are considered. To generate numerous and accurate training samples for the deep learning model, an autoencoder combining the convolutional neural network (CNN) with EDM is established, in which a setting mask function is set to quickly and accurately determine the mainlobe and sidelobe intervals at different pointing angles.

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.