ISSN 
1999 Vol. 28, No. 4
1999, 28(4): 333-336.
Abstract:
An absorbing boundary condition(ABC) for both traveling and evanescent waves within waveguides is presented. By combination a convention ABC, it is proved that the ABC can be placed near a discontinuity without lossing the precision of the calculations, which results in reductions of CPU time and the computer memory. Numerical examples show that there is a good agreement between the data computed under the new ABC and the ones under the convention ABC.
An absorbing boundary condition(ABC) for both traveling and evanescent waves within waveguides is presented. By combination a convention ABC, it is proved that the ABC can be placed near a discontinuity without lossing the precision of the calculations, which results in reductions of CPU time and the computer memory. Numerical examples show that there is a good agreement between the data computed under the new ABC and the ones under the convention ABC.
1999, 28(4): 337-339.
Abstract:
iIn this paper, a brief describe of Laser guide star principle is given at first. The requirement of the 532nm laser energy is calculated with radar equation according to the back scattering characters measured by Nd:YAG laser.
iIn this paper, a brief describe of Laser guide star principle is given at first. The requirement of the 532nm laser energy is calculated with radar equation according to the back scattering characters measured by Nd:YAG laser.
1999, 28(4): 340-345.
Abstract:
The characteristics of illuminated fields formed dua beam including are discussed plane waves, spherical waves and plane wave and spherical wave. By analyzing the echo wave signal scattered by an object moving through the illuminated interference field, it is concluded that the optimal illuminated field is the interference field produced by the plane wave and the spherical wave, can be used in the interferemeter imaging.
The characteristics of illuminated fields formed dua beam including are discussed plane waves, spherical waves and plane wave and spherical wave. By analyzing the echo wave signal scattered by an object moving through the illuminated interference field, it is concluded that the optimal illuminated field is the interference field produced by the plane wave and the spherical wave, can be used in the interferemeter imaging.
1999, 28(4): 346-352.
Abstract:
Millimeter wave circuits for precise guided weapons and channelized receivers are discussed in this paper. Low cost and producibility in large quantities are the dominant requirements for this new generation of RF hardware Two main integrated circuit techniques include the hybrid and monolithic. In a production transceiver configuration, a combination between hybrid and monolithic appears to yield the best performance and to be the most cost effective recommendable mode.
Millimeter wave circuits for precise guided weapons and channelized receivers are discussed in this paper. Low cost and producibility in large quantities are the dominant requirements for this new generation of RF hardware Two main integrated circuit techniques include the hybrid and monolithic. In a production transceiver configuration, a combination between hybrid and monolithic appears to yield the best performance and to be the most cost effective recommendable mode.
1999, 28(4): 353-356.
Abstract:
According to the idea of extracting harmonic power while phase locking the fundamental,a phase locked W band second harmonic two port Gunn oscillator is developed, with two phase locked loops. The relationship of phase shaking between the signals of millimeter wave and intermediate frequency is analyzed. Meanwhile the limitation of phase noise determined by internal phase locked intermediate frequency is pointed out. The phase locked oscillator, whose output power is over 10 mW and phase noise is -70 dBc/Hz@50 kHz, may be use as local oscillator or others.
According to the idea of extracting harmonic power while phase locking the fundamental,a phase locked W band second harmonic two port Gunn oscillator is developed, with two phase locked loops. The relationship of phase shaking between the signals of millimeter wave and intermediate frequency is analyzed. Meanwhile the limitation of phase noise determined by internal phase locked intermediate frequency is pointed out. The phase locked oscillator, whose output power is over 10 mW and phase noise is -70 dBc/Hz@50 kHz, may be use as local oscillator or others.
1999, 28(4): 357-361.
Abstract:
In this paper, numerical computation about relative dependence of planar single layer chiral medium on its electromagnetic characteristic parameter ε,μ,ζ and chiral coated-layer's thickness d is presented. According to the computed result shows that chiral parameter ζ may not always improve absorption of chiral coated layer. The normal chiral parameter ζr=1 if absorption is the best in the situation which chiral parameter improves the absorption of chiral coated-layer. It is concluded that the reflectance may decrease to some constant when the thickness increases to some limited value. Of course, the electromagnetic characteristic parameters change, the limited thickness change too. Permittivity and permeability also affect the reflectance of the chiral coated-layer.
In this paper, numerical computation about relative dependence of planar single layer chiral medium on its electromagnetic characteristic parameter ε,μ,ζ and chiral coated-layer's thickness d is presented. According to the computed result shows that chiral parameter ζ may not always improve absorption of chiral coated layer. The normal chiral parameter ζr=1 if absorption is the best in the situation which chiral parameter improves the absorption of chiral coated-layer. It is concluded that the reflectance may decrease to some constant when the thickness increases to some limited value. Of course, the electromagnetic characteristic parameters change, the limited thickness change too. Permittivity and permeability also affect the reflectance of the chiral coated-layer.
1999, 28(4): 362-365.
Abstract:
Gap discontinuities appear in many stripline circuits, such as the multilayer microwave monolithic ICs and the interconnect systems in high-speed digital circuits. In this paper, a multilayer perceptron neural network(MLPNN) is used to model the gap discontinuities in stripline circuits. The MLPNN is electromagnetically developed with a set of training data that are produced by the full-wave finite-difference time-domain method. The full-factor design of experiments is used for determining the size of the training data.
Gap discontinuities appear in many stripline circuits, such as the multilayer microwave monolithic ICs and the interconnect systems in high-speed digital circuits. In this paper, a multilayer perceptron neural network(MLPNN) is used to model the gap discontinuities in stripline circuits. The MLPNN is electromagnetically developed with a set of training data that are produced by the full-wave finite-difference time-domain method. The full-factor design of experiments is used for determining the size of the training data.
1999, 28(4): 366-370.
Abstract:
Basic parameters of the coplanar strip line on the substrate with finite dimensions are discussed in this paper. The coplanar strip line on the substrate with finite dimensions is a physical model, which is very closed to the engineering situation. The coplanar strip lines are analyzed using conformal mapping techniques. The exact solutions including the effective dielectric constant, the capacitance per unit length and the characteristic impedance are obtained. The results obtained in this paper have been compared with that of the coplanar strip line with infinite wide substrate. The relationship between the approximation error and the width of the substrate are given when using CPS3 as the approximation solution of CPS4. Multi-layered substrate coplanar strip line with finite dimensions is also discussed.
Basic parameters of the coplanar strip line on the substrate with finite dimensions are discussed in this paper. The coplanar strip line on the substrate with finite dimensions is a physical model, which is very closed to the engineering situation. The coplanar strip lines are analyzed using conformal mapping techniques. The exact solutions including the effective dielectric constant, the capacitance per unit length and the characteristic impedance are obtained. The results obtained in this paper have been compared with that of the coplanar strip line with infinite wide substrate. The relationship between the approximation error and the width of the substrate are given when using CPS3 as the approximation solution of CPS4. Multi-layered substrate coplanar strip line with finite dimensions is also discussed.
1999, 28(4): 371-373.
Abstract:
A new analysis for phase noise of microwave FET oscillator is given in this paper, which analyzes the steady respond and the phase noise property of the fundamental signal and every order harmonic with the nonlinear current source technique. It unifies the analyses of the steady respond and the phase noise, applied on microwave oscillator CAD. CAA results are agreed with empirical method results.
A new analysis for phase noise of microwave FET oscillator is given in this paper, which analyzes the steady respond and the phase noise property of the fundamental signal and every order harmonic with the nonlinear current source technique. It unifies the analyses of the steady respond and the phase noise, applied on microwave oscillator CAD. CAA results are agreed with empirical method results.
1999, 28(4): 374-377.
Abstract:
A novel millimeter-wave E-plane hybrid integrated power combiner using Gunn diode chips is presented, and its designing method is also introduced. By combining E-plane suspend coupled strip with finline transmission line, this two chips power combiner working at Ka-band has 550 MHz mechanical tuning bandwidth within which the maximum power is 305 mW and minimum power over 200 mW at the output waveguide port.
A novel millimeter-wave E-plane hybrid integrated power combiner using Gunn diode chips is presented, and its designing method is also introduced. By combining E-plane suspend coupled strip with finline transmission line, this two chips power combiner working at Ka-band has 550 MHz mechanical tuning bandwidth within which the maximum power is 305 mW and minimum power over 200 mW at the output waveguide port.
1999, 28(4): 378-382.
Abstract:
According to the design of 3 mm-wave radar, an amplifier-chain scheme of the coherent pulsed transmitter is proposed. The chain consists of a fundamental injection-locked harmonic Gunn oscillator, a CW IMPATT oscillator and two pulsed IMPATT oscillators in cascade. In order to overcome the effect of the leak signal in the system, a new technique of suppressing the leak in the intervals of pulse by altering the frequency is created and realized in success. The developed transmitter provides the output of 5 W peak power and 30 ns pulse-width in 3 mm-wave with the input of 2 mW signal in 6 mm-wave.
According to the design of 3 mm-wave radar, an amplifier-chain scheme of the coherent pulsed transmitter is proposed. The chain consists of a fundamental injection-locked harmonic Gunn oscillator, a CW IMPATT oscillator and two pulsed IMPATT oscillators in cascade. In order to overcome the effect of the leak signal in the system, a new technique of suppressing the leak in the intervals of pulse by altering the frequency is created and realized in success. The developed transmitter provides the output of 5 W peak power and 30 ns pulse-width in 3 mm-wave with the input of 2 mW signal in 6 mm-wave.
1999, 28(4): 383-387.
Abstract:
The complicated structure can be divided into several almost regular domains using decomposition domain method (DDM). In this paper, finite difference method(FD)is used to discretize the Helmholtz equation applied with five-points difference discretization. On the regular domain, the fast Fourier transform(FFT)is presented to transform the difference equations to a group of trigonal equations. The theory analysis and numerical results show that the computation complex of this algorithm is about O(PlgP).
The complicated structure can be divided into several almost regular domains using decomposition domain method (DDM). In this paper, finite difference method(FD)is used to discretize the Helmholtz equation applied with five-points difference discretization. On the regular domain, the fast Fourier transform(FFT)is presented to transform the difference equations to a group of trigonal equations. The theory analysis and numerical results show that the computation complex of this algorithm is about O(PlgP).
1999, 28(4): 388-391.
Abstract:
This paper analyzes the performance of DDS hybrid PLL circuit which is now existing, and presents a novel method to design an S-band frequency synthesizer using a new scheme of DDS hybrid PLL circuit. After describing this method, an example using this method is provided,which is also simulated and optimized with CAD tools.
This paper analyzes the performance of DDS hybrid PLL circuit which is now existing, and presents a novel method to design an S-band frequency synthesizer using a new scheme of DDS hybrid PLL circuit. After describing this method, an example using this method is provided,which is also simulated and optimized with CAD tools.
1999, 28(4): 392-396.
Abstract:
In this paper, a simulation model of feeder high impedance arc fault in traction supply system is established and discussed in detail, and the signal characters of the arc fault are discussed Then, this paper proposed a protection approach based on the neural network, which provides a new approach for adaptive protective relaying and adaptive detection of complex faults in traction supply system.
In this paper, a simulation model of feeder high impedance arc fault in traction supply system is established and discussed in detail, and the signal characters of the arc fault are discussed Then, this paper proposed a protection approach based on the neural network, which provides a new approach for adaptive protective relaying and adaptive detection of complex faults in traction supply system.
1999, 28(4): 397-401.
Abstract:
Lucas public key cryptosystem combines effectively Lucas sequence of Number theory with public key cryptosystem. Based on that, system's security is discussed in this paper. By discussing several attack ways which possibly attack this public key system, it is improved that the Lucas system is one public key cryptosystem based on two assumption. The effectiveness and security can be presented by the system.
Lucas public key cryptosystem combines effectively Lucas sequence of Number theory with public key cryptosystem. Based on that, system's security is discussed in this paper. By discussing several attack ways which possibly attack this public key system, it is improved that the Lucas system is one public key cryptosystem based on two assumption. The effectiveness and security can be presented by the system.
1999, 28(4): 402-404.
Abstract:
This paper presents a new method for inferring the probability distribution of cell loss ratio in ATM networks based on Bayes theory. The principle using fuzzy neural networks to optimize the fuzzy estimation and classification subsystem is also discussed.
This paper presents a new method for inferring the probability distribution of cell loss ratio in ATM networks based on Bayes theory. The principle using fuzzy neural networks to optimize the fuzzy estimation and classification subsystem is also discussed.
1999, 28(4): 405-409.
Abstract:
This paper introduces a microcomputer based control system for overhead contact line witches in electrified railways. System construction, hardware architecture and software design are also introduced. The operation of the system in laboratory and field shows that the design is successful.
This paper introduces a microcomputer based control system for overhead contact line witches in electrified railways. System construction, hardware architecture and software design are also introduced. The operation of the system in laboratory and field shows that the design is successful.
1999, 28(4): 410-414.
Abstract:
In this paper,the problem of dynamical distortion for airborne imaging ladar are analyzed and studied with computer simulation. The mechanism of distortion of Ladar target imaging following the six freedom move of the airborne are analyzed systematically. Every freedom move of the airborne lead up to distinct distortion are simulated and analyzed separately. This paper presents the results of simulation analysis of imaging distortion for 2D plane targets and 3D earth based target. These figurative results describe audio visualy distinct distortion. The simulation results of dynamical distortion are very useful and worthful, which provide scientific basis for studing the amending necessity and determining the correction in various real application of imaging ladar.
In this paper,the problem of dynamical distortion for airborne imaging ladar are analyzed and studied with computer simulation. The mechanism of distortion of Ladar target imaging following the six freedom move of the airborne are analyzed systematically. Every freedom move of the airborne lead up to distinct distortion are simulated and analyzed separately. This paper presents the results of simulation analysis of imaging distortion for 2D plane targets and 3D earth based target. These figurative results describe audio visualy distinct distortion. The simulation results of dynamical distortion are very useful and worthful, which provide scientific basis for studing the amending necessity and determining the correction in various real application of imaging ladar.
1999, 28(4): 415-418.
Abstract:
In this paper, several kinds of coding scheme for optical code division multiple access are introduced, and then their advantages/shortcoming are analyzed and compared. A new coding scheme based on the transmission and detection of bipolar sequences in a unipolar system is presented, which is thought to be suitable for wireless optical code division multiple access communication system.
In this paper, several kinds of coding scheme for optical code division multiple access are introduced, and then their advantages/shortcoming are analyzed and compared. A new coding scheme based on the transmission and detection of bipolar sequences in a unipolar system is presented, which is thought to be suitable for wireless optical code division multiple access communication system.
1999, 28(4): 419-422.
Abstract:
This paper reports the jobs of some authers in the recent three years, which include the basic principle and the primary bread board experiment of the laser interference imaging lidar. It is shown that the laser interference imaging lidar is principlly feasible and is quite possible to be a new ways in the area of the laser imaging since it has evident advantages comparing with traditional methods.
This paper reports the jobs of some authers in the recent three years, which include the basic principle and the primary bread board experiment of the laser interference imaging lidar. It is shown that the laser interference imaging lidar is principlly feasible and is quite possible to be a new ways in the area of the laser imaging since it has evident advantages comparing with traditional methods.
1999, 28(4): 423-427.
Abstract:
In this paper, a review of properties of cirrus is given. The knowledge of composition and structure of cirrus is described. Then, the geometric ray tracing method is proposed, which is first applied in this field by Cai and Liou. C-L method is approximately valid because the ice crystal of cirrus is more larger than wavelength of the researched laser. This computation depends on the optics, which can give the scattering phase matrix of polarized light for the randomly oriented non-spherical particle. As result, the matrix element of scattering of hexagonal ice crystal, the scattering cross sector and absorption cross sector is calculated.
In this paper, a review of properties of cirrus is given. The knowledge of composition and structure of cirrus is described. Then, the geometric ray tracing method is proposed, which is first applied in this field by Cai and Liou. C-L method is approximately valid because the ice crystal of cirrus is more larger than wavelength of the researched laser. This computation depends on the optics, which can give the scattering phase matrix of polarized light for the randomly oriented non-spherical particle. As result, the matrix element of scattering of hexagonal ice crystal, the scattering cross sector and absorption cross sector is calculated.
1999, 28(4): 428-431.
Abstract:
The thermal effects of high power laser diode array (LDA) side-pumped solid state laser are studied and a theoretical model is established. Based on simulated the model, laser depolarized density distrbution in the perpendicular of active medium and the change in focus length of the thermal lens at the different pumping density are simulated with different pumping construction and different cooling condition of the lasers. The compensation on thermal effects is also discussed.
The thermal effects of high power laser diode array (LDA) side-pumped solid state laser are studied and a theoretical model is established. Based on simulated the model, laser depolarized density distrbution in the perpendicular of active medium and the change in focus length of the thermal lens at the different pumping density are simulated with different pumping construction and different cooling condition of the lasers. The compensation on thermal effects is also discussed.
1999, 28(4): 432-436.
Abstract:
The experiment result of Hα radiated photos taken by CCD camera is described in HL 1M device. The photo of various ablation cloud, pellet speed and trajectory are obtained. Through the photo treatment,the space distribution of the radiation is given. The track bending and the appearance of striation are analyzed, inquiring into the physical mechanism of pellet-plasma interactions. Therefore this paper lays the foundation of further measurement for local magnetic field and current profile of plasma with CCD camera under the condition of pellet injection
The experiment result of Hα radiated photos taken by CCD camera is described in HL 1M device. The photo of various ablation cloud, pellet speed and trajectory are obtained. Through the photo treatment,the space distribution of the radiation is given. The track bending and the appearance of striation are analyzed, inquiring into the physical mechanism of pellet-plasma interactions. Therefore this paper lays the foundation of further measurement for local magnetic field and current profile of plasma with CCD camera under the condition of pellet injection
1999, 28(4): 437-442.
Abstract:
The turbulence spectrum and intermittency problem concerning light propagation in the atmosphere are addressed. The validity and limitation of current turbulence spectrum models are discussed, and roles of turbulence characteristic scales are analyzed. A experimentally tested model for temperature structure functions in fully developed turbulence is developed. The model can be used for the construction of the random phase screen in the numerical simulation of light propagation in order to study the effect of turbulence intermittency on light propagation.
The turbulence spectrum and intermittency problem concerning light propagation in the atmosphere are addressed. The validity and limitation of current turbulence spectrum models are discussed, and roles of turbulence characteristic scales are analyzed. A experimentally tested model for temperature structure functions in fully developed turbulence is developed. The model can be used for the construction of the random phase screen in the numerical simulation of light propagation in order to study the effect of turbulence intermittency on light propagation.
1999, 28(4): 443-446.
Abstract:
In this paper, some current antenna mounting systems used in the satellite communication and their corresponding key holes are described. A method of using Stewart robot for antenna mounting to solve key hole Problem is discussed. The possibility of using it in space laser communication is also considered.
In this paper, some current antenna mounting systems used in the satellite communication and their corresponding key holes are described. A method of using Stewart robot for antenna mounting to solve key hole Problem is discussed. The possibility of using it in space laser communication is also considered.
1999, 28(4): 447-451.
Abstract:
In this paper, the application of laser radar in space rendezvous and docking is introduced, The principle of how alaser radar works as a rendezvous detector, and the way it is implementde in detecting range,speed and angle are discussed.
In this paper, the application of laser radar in space rendezvous and docking is introduced, The principle of how alaser radar works as a rendezvous detector, and the way it is implementde in detecting range,speed and angle are discussed.
