Daojie Yu

The unmanned aerial vehicle (UAV) has drawn attention from the military and researchers worldwide, which has advantages such as robust survivability and execution ability. Mobility models are usually used to describe the movement of nodes in drone networks. Different mobility models have been proposed for different application scenarios; currently, there is no unified mobility model that can be adapted to all scenarios. The mobility of nodes is an essential characteristic of mobile ad hoc networks (MANETs), and the motion state of nodes significantly impacts the network’s performance. Currently, most related studies focus on the establishment of mathematical models that describe the motion and connectivity characteristics of the mobility models with limited universality. In this study, we use a backpropagation neural network (BPNN) to explore the relationship between the motion characteristics of mobile nodes and the performance of routing protocols. The neural network is trained by extracting five indicators that describe the relationship between nodes and the global features of nodes. Our model shows good performance and accuracy of classification on new datasets with different motion features, verifying the correctness of the proposed idea, which can help the selection of mobility models and routing protocols in different application scenarios having the ability to avoid repeated experiments to obtain relevant network performance. This will help in the selection of mobility models for drone networks and the setting and optimization of routing protocols in future practical application scenarios.

In this paper, the electromagnetic interference and temperature coupling on MOS transistor is analyzed. The temperature controlled platform that combined with the standardized direct power injection method is designed for experimental measurement. Then the temperature effect on MOS device is considered into the conducted electromagnetic immunity model of input/output element (IOE) for typical field programmable gate array. Meanwhile, the proposed immunity model ICIM-CI-T (integrated circuits immunity model-conducted immunity-temperature), which is based on ICIM-CI, is built to predict the influence of thermal effect on the electromagnetic immunity of IOE. Finally, the validation of the ICIM-CI-T model is verified by experimental measurements, and both simulation and measurement results fit very well at different temperatures. Moreover, it is also observed that temperature exerts different effects on the immunity characteristic of IOE with the change of radio frequency interference frequency.

To distinguish the dielectric surface breakdown from the atmospheric breakdown, one method for atmospheric breakdown experiment by loading dielectric focusing lens is proposed. The focusing characteristics of dielectric focusing lens are investigated for the microwave frequency on the order of 1.3GHz to 9.3GHz, the lens focal length on the order of 0.3m to 0.9m and the dielectric constant on the order of 0.3 to 0.9. Simulations show that higher frequency, shorter focal length, and fitter dielectric constant result in better focus effect that the rising and falling edges of electric field strength change faster near the focus which is closer to the theoretical value. A dielectric focusing lens for the S-band is optimally designed with the polytetrafluoroethylene of 0.32m thickness, 0.6m diameter, and 0.4m focal length. The focus indicator of dielectric lens is measured and the atmospheric breakdown experiment is carried out. The experimental values of atmospheric breakdown are consistent with the theoretical values. The electric field strength with the lens at the focus is 5-6 times greater than that without focusing lens. The image of atmospheric breakdown by the dielectric lens focusing method experiment is clearer than that by the direct radiation method.

The characters of high power microwave propagating in atmosphere are related to the propagation links. And the intensive electric field of high power microwave highly affects the circumstance of its propagation links. Different characters and different research models in different layers are adopted in the research of high power microwave. A consolidated model-mixed-gas model- is presented in this paper. Dispersion formula and refractive index of high power microwave propagation in mixed-gas are derived. Mixed-gas model can be self-consistently transitional to all the layers of atmosphere in proper condition.