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.

This paper demonstrates an inkjet-printed quasi metasurface(QMS) flexible harvester for microwave power transfer(MPT). The substrate and radiator are separately based on Polyimide and EGaIn(Eutectic gallium indium alloy, in which the mass fraction of Ga and In are 75.5% and 24.5%, respectively). Due to the high electromagnetic energy loss of flexible materials, the electric field distribution is improved by etching on the transmission structure, consequently, the energy loss of the material is reduced. The simulated results show that under vertical incidence at 5.8 GHz by trench etching operation, the absorption efficiency(AE) and harvesting efficiency(HE) are both increased from 93% and 65% to 99% and 82%, respectively. The measured results show that the maximum HE is up to 78%, more than 60% HE can be maintained under multi-angle incident waves and more than 70% HE can be maintained in different conformal cases.

In this letter, a novel impedance matcher (IM) is designed based on Zeta converter to overcome the shortcomings of other impedance matching methods and improve the load range in low resistances. System-level verification demonstrates that the novel IM has a potential application value for microwave wireless power transmission (MWPT) system. Measurement results show the maximum power conversion efficiency (PCE) of the novel rectifier with IM can reach 73% when the input power is 32 dBm. In addition, the proposed rectifier circuit with IM can operate with above 60% overall efficiency when the load varies from 0.01 to 10 $\text{k}\Omega $ (1:1000) as input power of 32 dBm. Compared with that without IM, the application of IM can increase the load range by at least 1100% when the rectifier efficiency is >50.7%. The measurement results demonstrate that the rectifier circuit has a better performance when connected to the novel IM.

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.

This paper reports an inkjet-printed radiation pattern reconfigurable (RPR) receiving antenna for wireless power transfer application with 2.45 GHz frequency. Conductive ink EGaIn and polyimide are employed as the radiator and the flexible substrate, respectively. The geometrical parameters of the proposed antenna are optimized to obtain a favorable matching of impedance, and the S₁₁ at 2.45 GHz is −22.71 dB, with good agreement between the simulation and measurement results. The reconfigurable characteristics of the pattern are achieved by the flexible antenna bent conformally, while the trends of S₁₁ are investigated under various bending radii of curvature. The performance of the RPR flexible antenna receiving RF energy under multi-angle incidences is verified experimentally.

In this paper, we propose a wide-incidence-angle insensitive reflective metasurface multi-polarization converter, using split-ring-resonators and cross oscillators structure. The simulated results indicate that the polarization conversion ratio for linear to linear (LTL) polarization conversion is greater than 90% in three frequency bands of 5.03–5.19 GHz (3.13%), 6.38–6.82 GHz (6.67%) and 7.38–7.44 GHz (0.81%). Meanwhile, the axial ratio for linear to circular (LTC) polarization conversion is less than 3 dB in four frequency bands of 4.79–5 GHz (4.29%), 5.24–6.27 GHz (17.90%), 6.94–7.35 GHz (5.74%) and 7.45–7.48 GHz (0.40%). LTL or LTC polarization conversion will not be affected when the incidence angle is tilted by 45° under both transverse electric and transverse magnetic modes. To verify the polarization conversion performance, a sample consisting of 18 × 18 unit cells is fabricated and measured. The measured results are found to be in reasonable agreement with the simulated results, demonstrating the potential application of this design for future microwave polarization state manipulation.