A triple-band electromagnetically induced transparency effect using two sub-resonators having the mechanism of two big-bright modes coupling is experimentally demonstrated, and the applications in sensing and slow light are also given.

A composite gradient-index metasurface (C-GM) array for microwave power reception (MPR) operating at 5.8 GHz center frequency was introduced. The array is insensitive to the polarization of incident plane waves and possesses cosine gradient modulation characteristics, which can convert the incident plane waves into surface waves focused at the center of the array. The focused surface wave energy is then collected by an omnidirectional antenna and fed back to a single rectifier for radio frequency (RF) to direct current (DC) conversion, resulting in DC output. Simulation results show that the array can fully excite surface waves under different polarized plane wave excitations, and the omnidirectional antenna has good matching characteristics with the array, achieving an energy collection efficiency of 66.52%. The array was fabricated and measured, achieving an energy reception efficiency of 59.91% and an RF-DC conversion efficiency of 34.83%, which is consistent with the simulation results. The proposed C-GM array can capture higher electromagnetic power by simply increasing its size, without the need for additional rectifiers or complex matching networks, making it a flexible and efficient MPR solution for different application scenarios.

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.

The detection of electromagnetic power in space is essential for the safe operation of electronic equipment systems. However, as the electromagnetic wave application scenarios become increasingly extensive and complex, it takes a serious challenge to effectively detect the power distribution of fixed-frequency electromagnetic waves over a large area at the same time. This paper proposes a metasurface microwave power detector based on a metal resonant disk and load resistors. The detector unit cells can form array of any shape and size, enabling the detection of electromagnetic wave power at arbitrary spatial sizes. The detector unit cell consists of a metal resonant disk, a dielectric layer, a metal backplane and load resistors. The metal resonant disk converts the received microwave to resonant current by resonance, then the resonant current flows through the load resistors and is converted as Joule heat, finally the microwave power density can be detected by analyzing the heat signal. Simulation results demonstrate that the detector exhibits high absorption efficiency, wide detection angle, and polarization insensitivity. Furthermore, the detector can detect the polarization state of the microwave without any attachments. To verify the proposed method, a 10 × 10 array model is fabricated and measured, and the measured results are found to be consistent with the simulation results. Overall, besides the excellent detection performance and flexibility, the proposed detector also has the advantages of simple structure and low production cost, providing a new solution for large-area microwave power detection.