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2004 Vol. 26, No. 2
Display Method:
2004, 26(2): 169-173.
Abstract:
To solve the problem of Moving Target Detection (MTD) and range-velocity decoupling in LFMCW Radars, a method combining MTD with frequency domain pairing is proposed. The method realizes detection and classification of moving targets with different ambiguous velocities via MTD in order to simplify the spectrum of beat signal, then eliminates moving targets range-velocity coupling based on the symmetry of the Doppler shift between positive and negative frequency sweep in triangular frequency modulation continu- ous waves. The effectiveness of the method is demonstrated by simulations.
To solve the problem of Moving Target Detection (MTD) and range-velocity decoupling in LFMCW Radars, a method combining MTD with frequency domain pairing is proposed. The method realizes detection and classification of moving targets with different ambiguous velocities via MTD in order to simplify the spectrum of beat signal, then eliminates moving targets range-velocity coupling based on the symmetry of the Doppler shift between positive and negative frequency sweep in triangular frequency modulation continu- ous waves. The effectiveness of the method is demonstrated by simulations.
2004, 26(2): 174-180.
Abstract:
Abstract Based on analyzing the restriction of high-resolution SAR to motion errors, a high-accuracy integrated SINS/GPS system for SAR compensation is proposed. By the adoption of two individual strapdown navigating algorithms, this system not only can fully inherit the advantage of SINS/GPS system, but also can isolate the high frequency GPS noise which has serious impaction on high resolution SAR imaging. The feasibility is proved by computer simulations and semi-physical simulations.
Abstract Based on analyzing the restriction of high-resolution SAR to motion errors, a high-accuracy integrated SINS/GPS system for SAR compensation is proposed. By the adoption of two individual strapdown navigating algorithms, this system not only can fully inherit the advantage of SINS/GPS system, but also can isolate the high frequency GPS noise which has serious impaction on high resolution SAR imaging. The feasibility is proved by computer simulations and semi-physical simulations.
2004, 26(2): 183-187.
Abstract:
Based on the analysis of the time and frequency domain character of the de-chirped broadband LFM signal, this paper presents the SRC imaging method of S AR with de-chirped LFM signal. In comparison with the RD and SRC method of normal LFM signal with the same swath and resolution, this method is proved suitable for real time processing with a decrease of data to be processed and a little amount of calculation increased. Data collected in de-chirp LFM SAR system is formed into images with this method and demonstrates it is better than RD to form fine-resolution images when there exits a squint angle in SAR system, which is usually the case in reality.
Based on the analysis of the time and frequency domain character of the de-chirped broadband LFM signal, this paper presents the SRC imaging method of S AR with de-chirped LFM signal. In comparison with the RD and SRC method of normal LFM signal with the same swath and resolution, this method is proved suitable for real time processing with a decrease of data to be processed and a little amount of calculation increased. Data collected in de-chirp LFM SAR system is formed into images with this method and demonstrates it is better than RD to form fine-resolution images when there exits a squint angle in SAR system, which is usually the case in reality.
2004, 26(2): 188-193.
Abstract:
In this paper, phase weighting method using genetic algorithm is presented in order to make pattern broaden, satisfying the need of swath. In addition, the broadened pattern is simulated. According to the broadened pattern, the SAR system parameter and the orbit parameter, the range and azimuth ambiguity levels and the system sensitivity are calculated and the results are given. Based on these results, beam positions are devised. The simulation results show that phase weighting method using genetic algorithm is feasible.
In this paper, phase weighting method using genetic algorithm is presented in order to make pattern broaden, satisfying the need of swath. In addition, the broadened pattern is simulated. According to the broadened pattern, the SAR system parameter and the orbit parameter, the range and azimuth ambiguity levels and the system sensitivity are calculated and the results are given. Based on these results, beam positions are devised. The simulation results show that phase weighting method using genetic algorithm is feasible.
2004, 26(2): 194-199.
Abstract:
In this paper, a new approach to two-dimensional phase unwrapping for in- terferon ictric SAR, based on local iuiniiiiitin spanning tree is presented deriving liy branch optimum model. This approach avoids separated interferograin into isolated regions resuh- ing in incomplete unwrapped phase by traditional connecting residues methods. Guided by quality snap, the connecting of residues is proposed exactly and optimized. The experiments on real interferograni show the validity of this approach.
In this paper, a new approach to two-dimensional phase unwrapping for in- terferon ictric SAR, based on local iuiniiiiitin spanning tree is presented deriving liy branch optimum model. This approach avoids separated interferograin into isolated regions resuh- ing in incomplete unwrapped phase by traditional connecting residues methods. Guided by quality snap, the connecting of residues is proposed exactly and optimized. The experiments on real interferograni show the validity of this approach.
2004, 26(2): 200-205.
Abstract:
This paper analyzes Doppler frequency rate, parameters of system and images quality , and provides the relationship among accuracy of Doppler frequency rate, resolution of images, parameters of radar system, accuracy of orbit data and electromagnetic parameters of imaging area. These results are useful for system design and data processing.
This paper analyzes Doppler frequency rate, parameters of system and images quality , and provides the relationship among accuracy of Doppler frequency rate, resolution of images, parameters of radar system, accuracy of orbit data and electromagnetic parameters of imaging area. These results are useful for system design and data processing.
2004, 26(2): 206-212.
Abstract:
The Doppler frequency of received signal is calculated by a Taylor series, the Cramer-Rao bounds on the estimation error is Derived and analyzed; The estimation techniques as Maximum Likelihood Estimator(MLE) and Extended Kalman Filter(EKF) are compared; Their basic frequency error performance and probability of loss-of-lock at various signal-to-noise ratios is compared by tracking a common simulated high-dynamic trajectory.
The Doppler frequency of received signal is calculated by a Taylor series, the Cramer-Rao bounds on the estimation error is Derived and analyzed; The estimation techniques as Maximum Likelihood Estimator(MLE) and Extended Kalman Filter(EKF) are compared; Their basic frequency error performance and probability of loss-of-lock at various signal-to-noise ratios is compared by tracking a common simulated high-dynamic trajectory.
2004, 26(2): 213-219.
Abstract:
This paper researches the relation of conjugate cyclostationary methods, and proposes a kind of pre-processing method of conjugate cyclic correlation. These methods make use of the information of the matrix of conjugate cyclic correlation is Hankel matrix. Therefore, pre-processing of Hankel Approximation Method (HAM) is proposed to cope with the low signal-noise ratio (SNR) situations. These methods can improve the performance of Direction-Of-Arrival (DOA), and its effectiveness are illustrated by the simulation results.
This paper researches the relation of conjugate cyclostationary methods, and proposes a kind of pre-processing method of conjugate cyclic correlation. These methods make use of the information of the matrix of conjugate cyclic correlation is Hankel matrix. Therefore, pre-processing of Hankel Approximation Method (HAM) is proposed to cope with the low signal-noise ratio (SNR) situations. These methods can improve the performance of Direction-Of-Arrival (DOA), and its effectiveness are illustrated by the simulation results.
2004, 26(2): 220-224.
Abstract:
In this paper, a new transform called Radon-Gabor transform(RGT) is proposed firstly, then the basic theory is introduced for Linear Frequency-Modulated (LFM) signal detection and parameter estimation using Radon-Gabor transform. Moreover, a new method combining Radon-Gabor transform with clean technique for multicomponent LFM signal detection and parameter estimation is presented. The computer simulation results show its effectiveness.
In this paper, a new transform called Radon-Gabor transform(RGT) is proposed firstly, then the basic theory is introduced for Linear Frequency-Modulated (LFM) signal detection and parameter estimation using Radon-Gabor transform. Moreover, a new method combining Radon-Gabor transform with clean technique for multicomponent LFM signal detection and parameter estimation is presented. The computer simulation results show its effectiveness.
2004, 26(2): 225-232.
Abstract:
An original Generalized Maximum Likelihood(GML) algorithm for dircction-of-arrival estimation is proposed in this paper. A new data model is established based on generalized steering vectors and generalized array manifold matrix. For the novel GML algorithm, the incident sources may be a mixture of multi-clusters of coherent sources, the arrays geometry is unrestricted and more importantly, the number of sources resolved can be larger than the number of sensors. The comparison between the GML algorithm and conventional DML algorithm is presented based on their respective geometrical interpretation. Subsequently the estimation consistency of GML is proved and the estimation variance of GML is derived. Theoretical analysis shows that the performance of GML algorithm is consistant with DMLs in incoherent sources case, and it improves greatly in coherent source case. Using the genetic algorithm, the GML algorithm is realized in the paper, and its efficacy is proved by means of the Monte-Carlo Simulations.
An original Generalized Maximum Likelihood(GML) algorithm for dircction-of-arrival estimation is proposed in this paper. A new data model is established based on generalized steering vectors and generalized array manifold matrix. For the novel GML algorithm, the incident sources may be a mixture of multi-clusters of coherent sources, the arrays geometry is unrestricted and more importantly, the number of sources resolved can be larger than the number of sensors. The comparison between the GML algorithm and conventional DML algorithm is presented based on their respective geometrical interpretation. Subsequently the estimation consistency of GML is proved and the estimation variance of GML is derived. Theoretical analysis shows that the performance of GML algorithm is consistant with DMLs in incoherent sources case, and it improves greatly in coherent source case. Using the genetic algorithm, the GML algorithm is realized in the paper, and its efficacy is proved by means of the Monte-Carlo Simulations.
2004, 26(2): 233-240.
Abstract:
Evidence modeling has become a bottleneck problem of restricting the application of D-S evidence theory currently. Dempster(1967) firstly brought forward an important conceptcompatibility relation based on the research of multi-value mapping. Shafer(1985) defined basic probability assignment functionthe model of evidence based on the compatibility relation later. By extending compatibility relation of belief function, the process of founding a generic evidential model is described for kinds of uncertainty in this paper. Compared with Apprious(1999) first model, the physical meaning of the process of founding the generic evidential model is much more explicit and the system info is much more integrated. This process of modeling has wider range of application than other modeling methods of evidence.
Evidence modeling has become a bottleneck problem of restricting the application of D-S evidence theory currently. Dempster(1967) firstly brought forward an important conceptcompatibility relation based on the research of multi-value mapping. Shafer(1985) defined basic probability assignment functionthe model of evidence based on the compatibility relation later. By extending compatibility relation of belief function, the process of founding a generic evidential model is described for kinds of uncertainty in this paper. Compared with Apprious(1999) first model, the physical meaning of the process of founding the generic evidential model is much more explicit and the system info is much more integrated. This process of modeling has wider range of application than other modeling methods of evidence.
2004, 26(2): 241-247.
Abstract:
Based on Minimum-Mean-Square-Error(MMSE) criterion, a kind of LMS algorithm with variable step size is proposed to suppress Multi-Access Interference (MAI) in asynchronous DS-CDMA system. Compare with similar variable step size LMS algorithm, computer simulation results show that the kind of detector is insensitive to the near-far effect and its structure is very simple. At the same time, it has lower bit error rate and faster speed of convergence and tracking without increasing computational complexity. In particular, the controlling parameters of proposed algorithm are not required to re-adjust, even if the channel parameter changes. So it can be widely used.
Based on Minimum-Mean-Square-Error(MMSE) criterion, a kind of LMS algorithm with variable step size is proposed to suppress Multi-Access Interference (MAI) in asynchronous DS-CDMA system. Compare with similar variable step size LMS algorithm, computer simulation results show that the kind of detector is insensitive to the near-far effect and its structure is very simple. At the same time, it has lower bit error rate and faster speed of convergence and tracking without increasing computational complexity. In particular, the controlling parameters of proposed algorithm are not required to re-adjust, even if the channel parameter changes. So it can be widely used.
The Performance of Generalized Time-Frequency Domain Two Dimensional Spread Spectrum in AWGN Channel
2004, 26(2): 248-253.
Abstract:
In this paper, a conception of general time-frequency domain 2-Dirnensional Spread Spectrum (2DSS) is proposed. The principles of the transmitter and receiver of the 2DSS communications for additive white Gaussian noise channels are discussed, the Bit Error Rate (BER) of this scheme is also analyzed. The simulation result of the BER of the 2DSS communications is provided. It shows that the simulation result and analyzed result are almost the same.
In this paper, a conception of general time-frequency domain 2-Dirnensional Spread Spectrum (2DSS) is proposed. The principles of the transmitter and receiver of the 2DSS communications for additive white Gaussian noise channels are discussed, the Bit Error Rate (BER) of this scheme is also analyzed. The simulation result of the BER of the 2DSS communications is provided. It shows that the simulation result and analyzed result are almost the same.
2004, 26(2): 254-259.
Abstract:
Synchronous Code-Division Multiple-Access (CDMA) techniques possess intrinsic protection against co-channel interference when orthogonal codes are used. However, in the presence of multipath propagation, the signals lose their orthogonality property, leading to increased cross correlation. In these cases, channel estimation may be needed in order to improve detection. The former algorithms for estimating the channel response of CDMA system are used for signal sampled with chip rate. The received signal sampled in chip rate does not satisfy the Nyquist theory and the channel may be not a minimumphase system that the former algorithms do not work. An algorithm for fractionally spaced channel estimation of a synchronous CDMA system is proposed that uses aperiodic spreading code. Simulations demonstrate the performance of proposed algorithm.
Synchronous Code-Division Multiple-Access (CDMA) techniques possess intrinsic protection against co-channel interference when orthogonal codes are used. However, in the presence of multipath propagation, the signals lose their orthogonality property, leading to increased cross correlation. In these cases, channel estimation may be needed in order to improve detection. The former algorithms for estimating the channel response of CDMA system are used for signal sampled with chip rate. The received signal sampled in chip rate does not satisfy the Nyquist theory and the channel may be not a minimumphase system that the former algorithms do not work. An algorithm for fractionally spaced channel estimation of a synchronous CDMA system is proposed that uses aperiodic spreading code. Simulations demonstrate the performance of proposed algorithm.
2004, 26(2): 260-265.
Abstract:
Spreading sequence for Frequency Hopping(FH) sequence can be generated with logistic map. This paper constructs a second-order chaotic map based on logistic map, proves its probability density distribution, and proposes a method to generate chaotic frequency-hopping sequence. It also analyzes character of even and odd correlations by numerical simulation. The results shows the sequence has excellent properties.
Spreading sequence for Frequency Hopping(FH) sequence can be generated with logistic map. This paper constructs a second-order chaotic map based on logistic map, proves its probability density distribution, and proposes a method to generate chaotic frequency-hopping sequence. It also analyzes character of even and odd correlations by numerical simulation. The results shows the sequence has excellent properties.
2004, 26(2): 266-271.
Abstract:
This paper proposes a new improved algorithm for symbol timing recovery in a multipath fading channel through computer simulations. The computing equation is derived. Also, the correspondent FPGA hardware circuit is designed. Computer simulations and the testing process in the HDTV prototype prove its low complexity, easiness of realizing and excellent performance.
This paper proposes a new improved algorithm for symbol timing recovery in a multipath fading channel through computer simulations. The computing equation is derived. Also, the correspondent FPGA hardware circuit is designed. Computer simulations and the testing process in the HDTV prototype prove its low complexity, easiness of realizing and excellent performance.
2004, 26(2): 272-277.
Abstract:
Optical Burst Switching (OBS) is a promising solution for realizing IP/DWDM. In this paper, two new data channel scheduling algorithms in OBS networks, Minimum Wavelength Conversion Times (MWCT) algorithm and Service Differentiation (SD) algorithm, are proposed. Computer simulation has demonstrated that MWCT algorithm leads to much fewer wavelength conversion times and the SD algorithm can provide better transmission reliability in OBS networks for high priority data comparing with the existing FF and LAUC algorithms.
Optical Burst Switching (OBS) is a promising solution for realizing IP/DWDM. In this paper, two new data channel scheduling algorithms in OBS networks, Minimum Wavelength Conversion Times (MWCT) algorithm and Service Differentiation (SD) algorithm, are proposed. Computer simulation has demonstrated that MWCT algorithm leads to much fewer wavelength conversion times and the SD algorithm can provide better transmission reliability in OBS networks for high priority data comparing with the existing FF and LAUC algorithms.
2004, 26(2): 278-283.
Abstract:
Forward link packet data service scheduling algorithm in mobile communication systems is researched in this paper. After analyzing a few kinds of familiar scheduling algorithms, a new scheduling algorithm is proposed. Both the theoretical analysis and the simulation results shows that this algorithm takes on several advantages. On the premise of satisfying the fairness criteria, it can increase the system throughput and decrease the average packet delay.
Forward link packet data service scheduling algorithm in mobile communication systems is researched in this paper. After analyzing a few kinds of familiar scheduling algorithms, a new scheduling algorithm is proposed. Both the theoretical analysis and the simulation results shows that this algorithm takes on several advantages. On the premise of satisfying the fairness criteria, it can increase the system throughput and decrease the average packet delay.
2004, 26(2): 284-290.
Abstract:
In this paper, an adaptive equalization algorithm used in Space-Time Block Coded (STBC) OFDM system with Alamouti scheme is proposed. In term of the orthogonal property of Alamouti scheme and the character of the OFDM system with multiple antenna transmitter, the proposed algorithm gets an equivalent model expression of receiver signal for STBC-OFDM system by flexible transform method; Studying on II matrix, inverse of size of 2K2K matrix in Block RLS(BRLS) can be obtained by getting the inverse of K matrices of 22 gotten by decomposing it, so that the complexity of computation and receiver has been decreased. The simulation results prove the validity and property of fast convergence of the proposed algorithm.
In this paper, an adaptive equalization algorithm used in Space-Time Block Coded (STBC) OFDM system with Alamouti scheme is proposed. In term of the orthogonal property of Alamouti scheme and the character of the OFDM system with multiple antenna transmitter, the proposed algorithm gets an equivalent model expression of receiver signal for STBC-OFDM system by flexible transform method; Studying on II matrix, inverse of size of 2K2K matrix in Block RLS(BRLS) can be obtained by getting the inverse of K matrices of 22 gotten by decomposing it, so that the complexity of computation and receiver has been decreased. The simulation results prove the validity and property of fast convergence of the proposed algorithm.
2004, 26(2): 291-297.
Abstract:
A new fast distributed p-cycle pre-configuration searching algorithm is proposed in this paper. It can speed up the searching process convergence from two aspects. (1) The multi-p-cycle found by the algorithm within one searching wave should be completed configuration through multi searching waves in classical algorithm. This is the reason why this method faster than classical one. (2) Our algorithm has been changed over from the cycle-based searching to the path-based searching. Using this technique, searching information converged on one node in classical algorithm will be split to its multiple adjacent nodes so reduce the performance requirement of node equipment. The p-cycles searched by the distributed algorithm have been filtered within adjacent node hence the searching process be comes faster. The simulation result also shows that the penalty to spare capacity consumed is very small in our algorithm as well as the obvious benefit on the number of searching wave descent.
A new fast distributed p-cycle pre-configuration searching algorithm is proposed in this paper. It can speed up the searching process convergence from two aspects. (1) The multi-p-cycle found by the algorithm within one searching wave should be completed configuration through multi searching waves in classical algorithm. This is the reason why this method faster than classical one. (2) Our algorithm has been changed over from the cycle-based searching to the path-based searching. Using this technique, searching information converged on one node in classical algorithm will be split to its multiple adjacent nodes so reduce the performance requirement of node equipment. The p-cycles searched by the distributed algorithm have been filtered within adjacent node hence the searching process be comes faster. The simulation result also shows that the penalty to spare capacity consumed is very small in our algorithm as well as the obvious benefit on the number of searching wave descent.
2004, 26(2): 298-302.
Abstract:
In this paper, the unified CORDIC algorithm is put forward by the improvement of iterative sequence and the presence of rational approximation. The unified algorithm of elementary functions is implemented with high speed. A coprocessor core using the improved algorithm is built by Verilog HDL. The core is very suitable for embedded application due to its small scale, high speed and simple control.
In this paper, the unified CORDIC algorithm is put forward by the improvement of iterative sequence and the presence of rational approximation. The unified algorithm of elementary functions is implemented with high speed. A coprocessor core using the improved algorithm is built by Verilog HDL. The core is very suitable for embedded application due to its small scale, high speed and simple control.
2004, 26(2): 303-306.
Abstract:
Disturbance depression is very important to the reliability of spaceborne TWTA and the Electronic Power Controller (EPC) is responsible for the disturbance depression of it. In this paper, based on small signal model and PSPICE, the responses to static and transit disturbance in the pre-regulation stage of EPC are analyzed. And the design for PID is given, the results are satisfactory.
Disturbance depression is very important to the reliability of spaceborne TWTA and the Electronic Power Controller (EPC) is responsible for the disturbance depression of it. In this paper, based on small signal model and PSPICE, the responses to static and transit disturbance in the pre-regulation stage of EPC are analyzed. And the design for PID is given, the results are satisfactory.
2004, 26(2): 307-311.
Abstract:
Both PCA and LDA are performed by only using the second-order statistics among image pixels, and not sensitive to high order statistics in the data. In this paper, the kernel function method is used to extract the high order relations, and the Linear Support Vector Machines (LSVM) is selected to perform the face classification. The experiment on Yale face database shows that the nonlinear feature extraction method is effective, and SVM is better than nearest neighbor classifier.
Both PCA and LDA are performed by only using the second-order statistics among image pixels, and not sensitive to high order statistics in the data. In this paper, the kernel function method is used to extract the high order relations, and the Linear Support Vector Machines (LSVM) is selected to perform the face classification. The experiment on Yale face database shows that the nonlinear feature extraction method is effective, and SVM is better than nearest neighbor classifier.
2004, 26(2): 312-317.
Abstract:
A method extracting moving object is proposed by utilizing the information fusion. Color image segmentation primarily uses a non-parametric clustering method based on partial space information intervening iterative mean shift procedure. A way of finding connected areas with identical marks is introduced to divide the image into different independent areas. HOS(Higher-Order Statistics) is used for motion detection. Then through post-processing, A rough motion template can be got. In such a template, the ratio of regions with identical marks to the corresponding independent region in the original image can be computed. If the ratio is larger than a predetermined threshold, the corresponding independent region will be fused. Finally, the moving object can be extracted by fusing all the predetermined regions to be fused.
A method extracting moving object is proposed by utilizing the information fusion. Color image segmentation primarily uses a non-parametric clustering method based on partial space information intervening iterative mean shift procedure. A way of finding connected areas with identical marks is introduced to divide the image into different independent areas. HOS(Higher-Order Statistics) is used for motion detection. Then through post-processing, A rough motion template can be got. In such a template, the ratio of regions with identical marks to the corresponding independent region in the original image can be computed. If the ratio is larger than a predetermined threshold, the corresponding independent region will be fused. Finally, the moving object can be extracted by fusing all the predetermined regions to be fused.
2004, 26(2): 318-321.
Abstract:
In this paper, the time varying forgetting factor exponentially weighted least square error criterion Jr(n)=nt=0 n-teT(n)Ce(n),is proposed by reducing the correlation function mean square error criterion Jr(n) = E[eT(n)Ce(n)] proposed by Asharif(1999). Applying gradient method on the proposed criterion, a new adaptive filtering algorithm for correlation function is proposed by orthogonalizing the current gradient vector to the previous gradient vector. Computer simulation results indicate that the proposed algorithms convergence performance is better than that of ECLMS algorithm proposed by Asharif.
In this paper, the time varying forgetting factor exponentially weighted least square error criterion Jr(n)=nt=0 n-teT(n)Ce(n),is proposed by reducing the correlation function mean square error criterion Jr(n) = E[eT(n)Ce(n)] proposed by Asharif(1999). Applying gradient method on the proposed criterion, a new adaptive filtering algorithm for correlation function is proposed by orthogonalizing the current gradient vector to the previous gradient vector. Computer simulation results indicate that the proposed algorithms convergence performance is better than that of ECLMS algorithm proposed by Asharif.
2004, 26(2): 322-325.
Abstract:
Non-repudiation is a security protocol to provide non-repudiation evidences for two transaction parties against the other falsely denying a particular event in electronic commerce while efficiency and fairness are what people have expected during electronic commerce. In this paper, a fair non-repudiation protocol based on bulletin-board is proposed to resolve the problem that a trusted third party brings into bottle-neck of communication. This protocol can achieve non-repudiation service in an efficient and practical way.
Non-repudiation is a security protocol to provide non-repudiation evidences for two transaction parties against the other falsely denying a particular event in electronic commerce while efficiency and fairness are what people have expected during electronic commerce. In this paper, a fair non-repudiation protocol based on bulletin-board is proposed to resolve the problem that a trusted third party brings into bottle-neck of communication. This protocol can achieve non-repudiation service in an efficient and practical way.
2004, 26(2): 326-331.
Abstract:
The eigenvalues of ridge waveguide are solved with the matching of electric and magnetic field on the multiple virtual boundaries by partial differential operator theory and the property of ridge waveguide is discussed. The dyadic Greens function has no singularity and can be transformed into scalar Greens function. The results computed by partial differential operator theory are compared with those computed by equivalent transmission line method.
The eigenvalues of ridge waveguide are solved with the matching of electric and magnetic field on the multiple virtual boundaries by partial differential operator theory and the property of ridge waveguide is discussed. The dyadic Greens function has no singularity and can be transformed into scalar Greens function. The results computed by partial differential operator theory are compared with those computed by equivalent transmission line method.
2004, 26(2): 332-336.
Abstract:
The auto-modeling of an arbitrary shaped conducting body is studied by the software AutoCAD firstly, and the surface model of the conducting body is achieved on base of many basic triangle meshes. Then the basic theory of the solution for the capacitance of an arbitrary shaped conducting body is presented by method of moment, and the closed-form of diagonal matrix elements and the numerical result of off-diagonal matrix elements are deduced. Finally, some examples of two-dimensional and three-dimensional bodies are given, at the same time the Richardsons extrapolations of these numerical results are calculated. The results agree well with the corresponding close-form and the reference value in literature. Thus the methods accuracy and high efficiency are illuminated.
The auto-modeling of an arbitrary shaped conducting body is studied by the software AutoCAD firstly, and the surface model of the conducting body is achieved on base of many basic triangle meshes. Then the basic theory of the solution for the capacitance of an arbitrary shaped conducting body is presented by method of moment, and the closed-form of diagonal matrix elements and the numerical result of off-diagonal matrix elements are deduced. Finally, some examples of two-dimensional and three-dimensional bodies are given, at the same time the Richardsons extrapolations of these numerical results are calculated. The results agree well with the corresponding close-form and the reference value in literature. Thus the methods accuracy and high efficiency are illuminated.
