The Applications of Nonuniform Equal-Length Coupled-Serial-Shunt Transmission-Line and Z Transform Techniques to Microwave Signal Processing
| Autor: | Kuo-Lung Chen, 陳國龍 |
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| Rok vydání: | 2004 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 92 In this thesis, we propose an approach to design and implement networks with capability of being microwave filters and differentiators. The basic idea is to form the networks by cascading serial and shunt transmission-line sections of unit electrical length. At first, we developed the formulations of transfer function of transmission-lines configurations that are cast in the Z domain for six fundamental elements. In other words, the characteristic of each element is represented by the chain scattering parameters in the Z domain. A synthesis approach making using of discrete-time process (DSP) techniques and optimization algorithm is proposed to implement circuit in the field of microwave engineers. The design phase begins with the adoption of a discrete-time filter or differentiator that satisfies the prescribed specifications. Based on the system function of the discrete-time filter or differentiator, we can determine the pattern of the network according to specific rules and begin the implementation phase. The stub-related zeros of the transfer function of the network are then moved to the denominator of the system function of the discrete-time filter or differentiator, and both functions are transformed into auto-regressive (AR) processes. The implementation phase is finally finished by using optimization methods to tune the values of the characteristic impedances of each transmission-line sections so that the coefficients describing both AR processes are as close to each other as possible in the minimum-square-error sense. This final step promises that the character of the transfer function of the network will follow that of the system function of the adopted discrete-time filter or differentiator. To provide validation of the proposed approach, two types of filters and two types of differentiators, namely, wide-band band-pass filter, narrow-band band-stop filter, first-order and second-order microwave differentiator, are implemented by using microstrip lines. The scattering parameters of the entire network are measured and compared with the ideal values to corroborate the approach in this thesis. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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