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1990 Vol. 12, No. 6
Display Method:
1990, 12(6): 561-568.
Abstract:
The complex astigmatic wave theory is used to analyse the electromagnetic characteristics of 3-D radome. A number of calculations for the ellipsoidal sandwich radome are performed, and the stereoscopic graphics are constructed. Comparing with the experimental results, it is shown that this method can be used to simplify the optimization designs for some kinds of 3-D radomes.
The complex astigmatic wave theory is used to analyse the electromagnetic characteristics of 3-D radome. A number of calculations for the ellipsoidal sandwich radome are performed, and the stereoscopic graphics are constructed. Comparing with the experimental results, it is shown that this method can be used to simplify the optimization designs for some kinds of 3-D radomes.
1990, 12(6): 569-574.
Abstract:
Based on Ohm-Rayleigh method and Laplace transform, the time-domain dyadic Green s functions for a ideal conducting wedge are obtained. The Characteristics of the wedge in time-domain are systematically analysed. Some conclusions are given, and C. T. Tai s theory (1973) is complemented. These studies are provided a further reference for time-domain analysis of an ideal conducting wedge.
Based on Ohm-Rayleigh method and Laplace transform, the time-domain dyadic Green s functions for a ideal conducting wedge are obtained. The Characteristics of the wedge in time-domain are systematically analysed. Some conclusions are given, and C. T. Tai s theory (1973) is complemented. These studies are provided a further reference for time-domain analysis of an ideal conducting wedge.
1990, 12(6): 575-583.
Abstract:
A modified boundary element method for analysing hybrid modes of waveguide is presented. The coupled boundary integral equations and their reduced forms are deduced for hybrid mode problems, and these equations are discreted into a system of linear algebraic equations by moment method. Finally the dispersion characteristics of rectangular waveguide filled with two kinds of dielectrics are calculated and the numerical results are in good agreement with that obtained by transverse resonating method.
A modified boundary element method for analysing hybrid modes of waveguide is presented. The coupled boundary integral equations and their reduced forms are deduced for hybrid mode problems, and these equations are discreted into a system of linear algebraic equations by moment method. Finally the dispersion characteristics of rectangular waveguide filled with two kinds of dielectrics are calculated and the numerical results are in good agreement with that obtained by transverse resonating method.
1990, 12(6): 584-592.
Abstract:
The split radix approach is generalized to length pm Discrete Hardy Transform (DHT). It is shown that the radix p/p2 algorithm is superior to the radix p2 and radix p algorithms in number of real multiplications. As an example, a radix 3/9 algorithm is developed for length-3m DHT, and the signal flowgraph is given.
The split radix approach is generalized to length pm Discrete Hardy Transform (DHT). It is shown that the radix p/p2 algorithm is superior to the radix p2 and radix p algorithms in number of real multiplications. As an example, a radix 3/9 algorithm is developed for length-3m DHT, and the signal flowgraph is given.
1990, 12(6): 593-599.
Abstract:
The optimization problem of constructing a K-edge-connected directed graph from any given directed graph by adding a minimum set of edges is studied. An efficient algorithm with complexity of O(|V|5) is presented. This algorithm contributes a foundation for the computer aided design of reliable networks.
The optimization problem of constructing a K-edge-connected directed graph from any given directed graph by adding a minimum set of edges is studied. An efficient algorithm with complexity of O(|V|5) is presented. This algorithm contributes a foundation for the computer aided design of reliable networks.
1990, 12(6): 600-606.
Abstract:
The unity gain buffer will be good for designing high frequency SCF if its resistive effect can be eliminated and then the overall parasitic sensitivity will be greatly lowered. Based on this concept, a new parasitic tolerant SC differential transconductance element (DTE) is proposed. SC floating inductor and integrator applicable to high frequency are formed by using the DTE. The computer simulation and experiment on a 3-order elliptic LP filter show the correctness of the concept.
The unity gain buffer will be good for designing high frequency SCF if its resistive effect can be eliminated and then the overall parasitic sensitivity will be greatly lowered. Based on this concept, a new parasitic tolerant SC differential transconductance element (DTE) is proposed. SC floating inductor and integrator applicable to high frequency are formed by using the DTE. The computer simulation and experiment on a 3-order elliptic LP filter show the correctness of the concept.
1990, 12(6): 607-613.
Abstract:
Recognization of modulation systems is an important problem in the modern electronic reconnaissance. A general method for solving this problem is suggested. From a segment of a captured signal, the modulation system can be determined, and its parameters can be extracted by using this method. The theoretical basis, algorithms and test results of this method are described. It is proved that the method is very effective in practical situation.
Recognization of modulation systems is an important problem in the modern electronic reconnaissance. A general method for solving this problem is suggested. From a segment of a captured signal, the modulation system can be determined, and its parameters can be extracted by using this method. The theoretical basis, algorithms and test results of this method are described. It is proved that the method is very effective in practical situation.
1990, 12(6): 614-627.
Abstract:
The numerical computation of processing error effect of lenses (i.e., the ellipticity and tilt of electrodes/pole-pieces in electron beam focusing and deflection systems) and its evaluation are discussed. First, the computation of the potential distributions of lenses with elliptical holes of tilt surfaces on electrodes/pole-pieces using the finite element method is described. Then, the formulae for evaluating the changes of the optical properties caused by the processing errors (i.e., the additional image shifting and additional aberrations) are derived. Finally, some illustrative examples of processing error effect evaluated by the computer programs developed are shown as the spot-diagrams.
The numerical computation of processing error effect of lenses (i.e., the ellipticity and tilt of electrodes/pole-pieces in electron beam focusing and deflection systems) and its evaluation are discussed. First, the computation of the potential distributions of lenses with elliptical holes of tilt surfaces on electrodes/pole-pieces using the finite element method is described. Then, the formulae for evaluating the changes of the optical properties caused by the processing errors (i.e., the additional image shifting and additional aberrations) are derived. Finally, some illustrative examples of processing error effect evaluated by the computer programs developed are shown as the spot-diagrams.
1990, 12(6): 628-635.
Abstract:
A Aluminate dispenser cathode with Y2O3 have been investigated by using modern surface analysis techniques (AES, XPS, SEM and THEM). The Surface topography, Surface chemistry and emission properties of the cathodes activated in situ have been obtained. The experimental results and activation mechanism are also discussed.
A Aluminate dispenser cathode with Y2O3 have been investigated by using modern surface analysis techniques (AES, XPS, SEM and THEM). The Surface topography, Surface chemistry and emission properties of the cathodes activated in situ have been obtained. The experimental results and activation mechanism are also discussed.
1990, 12(6): 636-640.
Abstract:
The design of a new type of sampling latching voltage comparator ZJ03 is described. The common voltage comparators consist of multistage DC amplifier. It is difficult to realize high speed and high precision. The voltage comparator ZJ03 contains a controlled positive feedback amplifier. Therefore, it is capable of realizing high speed and high precision. For improving the performance and yield, the tolerance extension, design centering and potential adapting are used for the design of the valtage comparator ZJ03.
The design of a new type of sampling latching voltage comparator ZJ03 is described. The common voltage comparators consist of multistage DC amplifier. It is difficult to realize high speed and high precision. The voltage comparator ZJ03 contains a controlled positive feedback amplifier. Therefore, it is capable of realizing high speed and high precision. For improving the performance and yield, the tolerance extension, design centering and potential adapting are used for the design of the valtage comparator ZJ03.
1990, 12(6): 641-645.
Abstract:
The port ratio faulty branch location method presented here is aimed at the peculiarity of 10 kV power network in China. By using this method, on line automatic diagnosis of the same place short fault is solved. This method has some features: the model s simplicity; operational convenience and high location accuracy.
The port ratio faulty branch location method presented here is aimed at the peculiarity of 10 kV power network in China. By using this method, on line automatic diagnosis of the same place short fault is solved. This method has some features: the model s simplicity; operational convenience and high location accuracy.
1990, 12(6): 646-649.
Abstract:
Based on the complex ray method and source expansion with a set of Gaussian beams, a new method for analysis and calculation of radar cross-section (RCS) of a complex target is presented. This method can be used for arbitrary shaped object, because complex ray analysis is not limited by the shape of object. A hollow rectangular pipe as a model of an air intake is investigated. The effectivenejs of this method can be proved from the comparison of calculated and measured results.
Based on the complex ray method and source expansion with a set of Gaussian beams, a new method for analysis and calculation of radar cross-section (RCS) of a complex target is presented. This method can be used for arbitrary shaped object, because complex ray analysis is not limited by the shape of object. A hollow rectangular pipe as a model of an air intake is investigated. The effectivenejs of this method can be proved from the comparison of calculated and measured results.
1990, 12(6): 650-655.
Abstract:
From relativistic linear Vlasov-Maxwell equations, the representations of the starting current and frequency deviation of a electrostatic gyromonotron with a field distribution sin k//z are derived and the numerical calculation are carried out.
From relativistic linear Vlasov-Maxwell equations, the representations of the starting current and frequency deviation of a electrostatic gyromonotron with a field distribution sin k//z are derived and the numerical calculation are carried out.
1990, 12(6): 656-659.
Abstract:
The technique for preparing cross-sectional specimen of semiconductor for TEM is shown. In such specimens prepared with the technique, an unexpected periodic compositional modulation in the fine low-dimensional structure named Fine Low Dimensional Modulated Fringes of GaAs/AlGaAs multilayers grown by MBE are observed. Some new patterns of dislocations, defects and microtwins etc. in GaAs/Si grown by both MBE and MOCVD are remarked. The technology can be adapted to the study of other systems of semiconductor materials also.
The technique for preparing cross-sectional specimen of semiconductor for TEM is shown. In such specimens prepared with the technique, an unexpected periodic compositional modulation in the fine low-dimensional structure named Fine Low Dimensional Modulated Fringes of GaAs/AlGaAs multilayers grown by MBE are observed. Some new patterns of dislocations, defects and microtwins etc. in GaAs/Si grown by both MBE and MOCVD are remarked. The technology can be adapted to the study of other systems of semiconductor materials also.
1990, 12(6): 660-665.
Abstract:
A new formula (0.2/[(r0+h)ln (2h/r0)]) which is used to determine the shape factor of field emission tip is reported. By using of this formula, the calculation of with the tip shape of half spheroid, rotational ellipsoid, rotational paraboloid and rotational hyperboloid have been made and compared with the calculated value of by D. Selidovkin, W. Swanson and P. Dyke and numerical method. It is shown that the value of calculated by using of the new formula is consistent with the result of calculation by computer and is more precise than that calculated by using of other method.
A new formula (0.2/[(r0+h)ln (2h/r0)]) which is used to determine the shape factor of field emission tip is reported. By using of this formula, the calculation of with the tip shape of half spheroid, rotational ellipsoid, rotational paraboloid and rotational hyperboloid have been made and compared with the calculated value of by D. Selidovkin, W. Swanson and P. Dyke and numerical method. It is shown that the value of calculated by using of the new formula is consistent with the result of calculation by computer and is more precise than that calculated by using of other method.
