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.

Magnetic sensor arrays have been widely used in current measurement, due to their advantages of small size, low power consumption, high sensitivity, wide bandwidth and large dynamic range. However, they all assume that the conductor is perpendicular to the plane of the sensor array and the error introduced by un-perpendicularity has not been eliminated until now. In this paper, a 3-D tunnel magnetoresistance (TMR) sensor array scheme with its correction algorithm for eccentric, inclined current-carrying conductor is proposed. The simulation comparison of the relative error caused by the inclined angle between 1-D, 2-D and 3-D TMR sensor arrays is performed, where the maximum errors are 25correction algorithm of 3-D TMR sensor array can significantly improve the accuracy. Four 3-D TMR sensors are used in the experimental prototype to verify the accuracy and reliability of the correction algorithm.

In this article, a high-input power (>30 dBm) rectifier circuit for 2.45-GHz microwave wireless power transmission is presented. To overcome the shortcomings of the traditional Schottky rectifier circuit, the novel rectifier circuit is designed based on a GaAs field-effect transistor (FET) and a Schottky diode together as the rectification part. A system-level verification demonstrates that the novel rectifier circuit has a potential application value for microwave wireless power transmission system. Measurement results show that higher input power range and MW-dc power conversion efficiency are realized at the same time by this design scheme. The maximum MW-dc conversion efficiency of the novel rectifier circuit can reach 74.42% when the input power is 30 dBm, and it is 20% higher than the peak conversion efficiency of the traditional rectifier without FET. In addition, the proposed rectifier circuit can operate with over 50% efficiency when the input power varies from 16 to 31 dBm, and has a good performance with the value of load ranging from 70 to 730 Ω, it is mean that the novel rectifier circuit is able to provide power for some electronic devices with different impedance.

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.