In this paper, a dual-channel RF-DC microwave rectifier circuit is designed with a 2:1 power distribution ratio in a Wilkinson power splitter. The rectifier circuit works at 2.45 Ghz. After impedance matching and tuning, the structure is able to broaden the dynamic power range of the rectifier circuit while maintaining maximum rectifier efficiency. Compared with the HSMS2820 rectifier branch, this design enhances the power dynamic ranges of 60% efficiency and 50% efficiency by 4 dBm and 3 dBm, respectively. Compared with the HSMS2860 rectifier branch, for the efficiency of 60% and efficiency of 50%, the power dynamic range is expanded by 5 dBm and 2 dBm, respectively. This shows that the technology is helpful for improving the stability of energy conversion at the receiver end of microwave wireless energy transmission systems. Finally, the rationality of this conclusion is verified by establishing a mathematical model.

Acousto-optic modulator (AOM) and electro-optical modulator (EOM) are applied to realize the all-fiber current sensor with a pulsed light source. The pulsed light is realized by amplitude modulation with AOM. The reflected interferometer current sensor is constructed by the mirror and phase modulation with EOM to improve the anti-interference ability. A correlation demodulation algorithm is applied for data processing. The influence of the modulation frequency and duty cycle of AOM on the optical system is determined by modeling and experiment. The duty cycle is the main factor affecting the normalized scale factor of the system. The modulation frequency mainly affects the output amplitude of the correlation demodulation and the system signal-to-noise ratio. The frequency multiplication factor links AOM and EOM, primarily affecting the ratio error. When the frequency multiplication factor is equal to the duty cycle of AOM and it is an integer multiple of 0.1, the ratio error of the system is less than 1.8% and the sensitivity and the resolution of AFOCS are 0.01063 mV/mA and 3 mA, respectively. The measurement range of AFOCS is from 11 mA to 196.62 A, which is excellent enough to meet the practical requirements for microcurrent measurement.

We present a method to simultaneously measure the temperature and electric current, which can be applied for the all-fiber optic current sensor (AFOCS) temperature compensation. The Faraday rotation mirror is introduced as the temperature sensing unit based on the all-fiber dual-modulation optic current sensor. The temperature and electric current could be distinguished by the sequence of pulse light received by the photodetector. The working principle of temperature and electric current sensing are analyzed by modeling and simulation. The experiments are designed to confirm the temperature compensation scheme. The relative error of AFOCS decreases from 14% to 2% by temperature compensation, which meets the requirements of micro-current fiber sensing.

The effects of the Faraday rotation mirror on the all-fiber optic current sensor (AFOCS) are studied in this paper. The reflectivity degradation of FRM with the long-term operation, the misalignment of the optical axis between FRM and the sensing fiber, and the influence of temperature fluctuation on FRM are modeled and simulated in this paper. The effect of temperature is the biggest obstacle to the application of the Faraday rotation mirror, while other factors can be easy to overcome by the data processing method. The experiments are designed and realized for verification. The temperature fluctuation range is related to the measured electric current to satisfy the required accuracy for IEC 60044-8 class 0.2S.

Intelligent monitoring of environmental information in ships is an important prerequisite for reducing and avoiding accidents and is of great importance for safety at sea. The use of a ship environmental monitoring system based on wireless sensor networks has the unique advantages of low cost, stability, and reliability, allowing real-time monitoring of many environmental factors in ships. This article proposes an optimal topology control to maximize collected data satisfaction and reduce energy consumption and transmission latency. First, the cluster head selection method is obtained by initializing the wireless sensor network with a fuzzy clustering algorithm, then the amount of collection data is obtained by a sub-gradient descent algorithm, and a sensor association scheme based on ant colony optimization is proposed to solve the knapsack problem. Finally, simulation results show that the proposed algorithm in this article can effectively reduce the energy consumption and transmission delay of the wireless sensor network while ensuring the monitoring of the grounding protection in the electrical system of the offshore ship.