The air breakdown in the high-power antenna near-field region limits the enhancement of the radiated power. A model coupling the field equivalent principle and the electron number density equation is presented to stud...The air breakdown in the high-power antenna near-field region limits the enhancement of the radiated power. A model coupling the field equivalent principle and the electron number density equation is presented to study the breakdown process in the near-field region of the circular aperture antenna at atmospheric pressure. Simulation results show that, although the electric field in the near-field region is nonuniform, the electron diffusion has small influence on the breakdown process when the initial electron number density is uniform in space. The field magnitude distribution on the aperture plays an important role in the maximum radiated power above which the air breakdown occurs. The maximum radiated power also depends on the phase difference of the fields at the center and edge of the aperture, especially for the uniform field magnitude distribution.展开更多
So far, the diffracted SAW field generated by an IDT with finite aperture on piezoelectric crystal surfaces is usually analyzed phenomenologically with the angular spectrum theory. A major approximation of this theory...So far, the diffracted SAW field generated by an IDT with finite aperture on piezoelectric crystal surfaces is usually analyzed phenomenologically with the angular spectrum theory. A major approximation of this theory is to ignore the vector nature of the field by assuming that the wave field can be represented by a scalar as in optics. In this paper, a rigorous vector field theory of the surface excitation of elastic wave field in piezoelectric crystal developed by the authors is used to evaluate the SAW diffraction field adepately and precisely. As an example, numerical results for YZ-LiNbO3 are presented and compared with those obtained form the angular spectrum theory.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61501358,11622542,61431010,and 61627901)the Fundamental Research Funds for the Central Universities,China
文摘The air breakdown in the high-power antenna near-field region limits the enhancement of the radiated power. A model coupling the field equivalent principle and the electron number density equation is presented to study the breakdown process in the near-field region of the circular aperture antenna at atmospheric pressure. Simulation results show that, although the electric field in the near-field region is nonuniform, the electron diffusion has small influence on the breakdown process when the initial electron number density is uniform in space. The field magnitude distribution on the aperture plays an important role in the maximum radiated power above which the air breakdown occurs. The maximum radiated power also depends on the phase difference of the fields at the center and edge of the aperture, especially for the uniform field magnitude distribution.
基金The project is supported by the National Natural Science Foundation of China
文摘So far, the diffracted SAW field generated by an IDT with finite aperture on piezoelectric crystal surfaces is usually analyzed phenomenologically with the angular spectrum theory. A major approximation of this theory is to ignore the vector nature of the field by assuming that the wave field can be represented by a scalar as in optics. In this paper, a rigorous vector field theory of the surface excitation of elastic wave field in piezoelectric crystal developed by the authors is used to evaluate the SAW diffraction field adepately and precisely. As an example, numerical results for YZ-LiNbO3 are presented and compared with those obtained form the angular spectrum theory.
