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Microwave detection based on resonant peak tracking is the basis of various types of microwave near-field sensors. In this article, a microwave near-field liquid level sensor based on an array of spoof localized surface plasmons (SLSPs) is proposed, which can be used to measure the liquid level in a nonmetallic container in real time. Two arrays of the same SLSPs are distributed on the two branches of the splitter/combiner microstrip sections and excited by it. When the horizontal liquid level rises, the corresponding resonant peaks are shifted, and when the liquid level is tilted, the symmetrical condition of the system will be broken, and the resonant peaks of the corresponding SLSPs will be split, two notches (i.e., frequency splitting) appear, and the resonant frequency will be changed. By analyzing the signal, the current liquid level situation and liquid level tilt angle can be judged. Taking an acrylic container as an example, simulations and experiments show that the sensor can measure the tilt angle with a max accuracy of up to 1°. Compared with other types of liquid level sensors, this sensor can penetrate the container for measurement and has the advantages of high accuracy, low cost, easy container integration, and can measure the liquid surface tilt angle.

In this article, a real-time liquid level detection sensor for a non-metal container is presented, which is composed of a spoof surface plasmon polaritons (SSPPs) transmission line and localized spoof surface plasmon (LSSPs) structure. The 14 LSSPs of different sizes have their own resonant frequencies and their responses are independent of each other. By analyzing the offset of the resonance frequencies, the liquid level can be obtained, and the liquid surface tilt angle can be further obtained. Simulations and experiments show that the performance of the sensor is highly dependent on the liquid dielectric constant and the thickness of the container wall. In the case of oil, for example, the maximum penetration depth of the sensor is 3 mm. Using the formula in this article, liquid level tilt angle measurement with an accuracy of up to 1° can be realized. Compared with other types of liquid-level sensors, this sensor can penetrate the container for measurement and has the advantages of high precision, low cost, flexibility, small volume, and measurability of liquid surface tilt angle.

Due to the high number of distributed generation units being connected to the power grid, multi-microgrids have emerged as an effective solution for integrating these units into the grid. Membrane computing is a powerful method for information processing and parallel computing, which is beneficial for solving distributed and parallel control problems. The spiking neural P systems with autapses (SNP-AU) are used to achieve power balance and coordinated control in multi-microgrids. To accomplish this goal, mathematical models and corresponding rules are established. By simulating the operation of microgrids under various scenarios through four reasoning test models, the correctness and feasibility of the proposed SNP-AU-based coordinated control model for the multi-microgrid are verified. Finally, the 24-h safe and stable operation of the multi-microgrid system is achieved through MATLAB simulation experiments, meeting the operational requirements for voltage and frequency.

In this article, a sensor for real-time online monitoring of the rotor axial displacement of an aeroengine based on a microwave coaxial resonator (MCR) is proposed. During the monitoring process, different axial displacements of the engine rotor will make MCR introduce different additional grounding capacitance, resulting in MCR generating different resonance statuses. Therefore, the monitoring and warning of the axial displacement of the engine rotor can be achieved by reading the resonance characteristics of the MCR in real time. Furthermore, the proposed sensor is also endowed with low-flow resistance characteristics since introducing the design of the diversion hole. Finally, the simulation and measurement results of the proposed sensor have the rotor axial displacement measuring and monitoring accuracy of $25\mu $ m within $2000\mu \text{m}$ , an average accuracy of $150\mu $ m within 2000– $5000\mu \text{m}$ , and a full monitoring range response bandwidth of 6.65 GHz (1.33 MHz/ $\mu \text{m}$ ). It can be predicted that the proposed sensor will be of greater value in the field of designing, testing, and health management of aeroengine.