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A new design of the high‐voltage superjunction VDMOS (SJ‐VDMOS) structure is proposed to minimise the reverse recovery losses of the body diode and the noise during the switching process. The key feature of the structure is that a discontinuous P + region in the source is implemented which can decrease the carrier injection efficiency. Numerical results indicate that the reverse recovery charge and the overshoot voltage of the proposed structure is decreased by 76.5% and 52.5%, respectively, compared to the conventional SJ‐VDMOS structure, while maintaining the same breakdown voltage.

To investigate micro-Doppler signatures of precession for a warhead with empennages, the model of precession is built and mathematical formulas of a micro-Doppler induced by different scattering centres are derived. The relationship between the micro-Doppler appearing frequency of empennages and micro-motion frequencies is first acquired, then two important precession features, namely coning frequency and spinning frequency, are extracted based on the micro-Doppler. Simulation results are provided to demonstrate the validity of the proposed method.

To investigate micro-Doppler signatures of precession for a warhead with empennages, the model of precession is built and mathematical formulas of a micro-Doppler induced by different scattering centres are derived. The relationship between the micro-Doppler appearing frequency of empennages and micro-motion frequencies is first acquired, then two important precession features, namely coning frequency and spinning frequency, are extracted based on the micro-Doppler. Simulation results are provided, to demonstrate the validity of the proposed method.

A new design of the high-voltage superjunction VDMOS (SJ-VDMOS) structure is proposed to minimise the reverse recovery losses of the body diode and the noise during the switching process. The key feature of the structure is that a discontinuous P + region in the source is implemented which can decrease the carrier injection efficiency. Numerical results indicate that the reverse recovery charge and the overshoot voltage of the proposed structure is decreased by 76.5% and 52.5%, respectively, compared to the conventional SJ-VDMOS structure, while maintaining the same breakdown voltage.

Non-reciprocal devices, such as circulators and isolators, are indispensable components in classical and quantum information processing in an integrated photonic circuit. Aside from those applications, the non-reciprocal phase shift is of fundamental interest for exploring exotic topological photonics, such as the realization of chiral edge states and topological protection. However, incorporating low optical-loss magnetic materials into a photonic chip is technically challenging. In this study, we experimentally demonstrate non-magnetic non-reciprocity using optomechanical interactions in a whispering-gallery microresonator, as proposed by Hafezi and Rabl. Optomechanically induced non-reciprocal transparency and amplification are observed, and a non-reciprocal phase shift of up to 40 degrees is demonstrated in this study. The results of this study represent an important step towards integrated all-optical controllable isolators and circulators, as well as non-reciprocal phase shifters.

The ergodic search in the generalised Radon-Fourier transform (GRFT) may have a huge computational complexity, and blind speed side lobes (BSSL) in the GRFT can lead to a high false alarm rate. Based on some specific relationships of the BSSL and the target's main lobe, an improved particle swarm optimisation is presented for the fast implementation of GRFT, and the BSSL problem can be solved simultaneously. Some real data experimental results are provided to verify the effectiveness and efficiency of this method. [PUBLICATION ABSTRACT]

This paper concentrates on an efficient marching-on-in-time (MOT)-based time domain integral equation (TDIE) method for the analysis of the transient electromagnetic scattering from perfect electrically conducting (PEC) coated by multilayer thin materials. Like its frequency domain counterpart, the proposed method can reduce the number of unknowns significantly while reasonable accuracy can be achieved. Numerical example is presented to demonstrate the accuracy and efficiency of the proposed method.

A HFSWR system with portable small array for ship targets surveillance has been developed recently. The antennas of the radar system contain a receiving antenna array of eight-elements and an omnidirectional transmitting antenna, which can be deployed rapidly when relocated to another radar site. The configuration and the relationship of each subsystem of the hardware system is described. A signal processing method of target monitoring is proposed, with the software system of ship surveillance developed. The performance of the HF radar system is validated by a field experiment of cooperation ship target in Yellow Sea.