許多運用Z轉換設計濾波器的文獻中，除了在設計方法上較缺乏理論基礎外，響應大多也存在著誤差，並且文獻中未加以解釋造成誤差之原因。本論文運用傳統濾波器設計觀點和電路分析方法，分析Z轉換設計，整理出兩大類設計實例，分別為低通濾波器及帶通濾波器設計進行探討。

分析Z轉換設計，提出Z轉換設計對於非冗餘性設計之誤解。在低通濾波器設計實例上，運用傳統方法設計與Ｚ轉換相同之實例，解釋Z轉換設計為何存在誤差。帶通濾波器設計實例上，指出Z轉換設計在響應階數上之錯誤。

透過設計與Z轉換相同實例，指出傳統設計比Z轉換設計更精準，所以若設計已有傳統方法可循之濾波器響應，運用傳統設計方法會比Z轉換設計更適合。

The documents of filter with Z-transform design often lack theoretical analysis, and the inaccurate response occurs without further explanation. This paper will compare filter with traditional design and Z-transform design, focusing specifically on low-pass and band-pass filters.

By comparing filter with traditional design and Z-transform design, the inaccurate response of Z-transform in the example of low-pass filter is indicated, and the erroneous filter order in the example of band-pass filter is shown. It will also point out the misestimate of Z-transform analysis at non-redundant design.

Hence, when traditional filter design is workable, it is a better choice than Z-transform design.

[1.1] Da-Chiang Chang and Ching-Wen Hsue, “Design and Implementation of Filters sing Transfer Function in the Z Domain,” IEEE Trans. Microwave Theory Tech., vol. 49, no. 5, pp. 979-985, May 2001.
[1.2] L. -C Tsai, H. -M. Chen and C. -W. Hsue, “Z-Domain Formulations of Equal-Length Coupled-Serial-Shunted Lines and their Applications to Filters,” IEE Proc.-Microw. Antennas Propag., vol. 151, no. 2, pp. 97-103, April 2004.
[1.3] L. -C Tsai, H. -M. Chen and C. -W. Hsue, “Dual-Band Bandpass Filters Using Equal-Length Coupled-Serial-Shunted Lines and Z-Transform Technique,” IEEE Trans. Microwave Theory Tech., vol. 52, no. 4, pp. 1111-1117, April 2004.
[2.1] G. L. Matthaei, L. Young, and E. M. T. Jones, Microwave Filters, Impedance-Matching Networks, and Coupling Structures, Norwood, MA: Artech House, 1980, ch4, pp. 83-130.
[2.2] P. I. Richards, “Resistor-Transmission-Line Circuits,” Proc. IRE, vol. 36, no. 2, pp. 217-220, February 1948.
[2.3] H. Ozaki and J. Jshii, “Synthesis of a Class of Strip-Line Filters,” IRE Trans. Circuit Theory, vol. CT-5, pp. 104-109, June 1958.
[2.4 ] Gabor C. Temes and Sanjit K. Mitra, Modern Filter Theory and Design, New York: John Wiley & Sons, 1973, ch7, pp. 285-286.
[2.5] M. C. Honton and R. J. Wenzel, “General theory and design of optimum quarter-wave TEM-Filters,” IEEE Trans. Microwave Theory Tech., vol. 13, no. 3, pp. 316-327, May 1965.
[2.6] S. B. Cohn, “Parallel-Coupled Transmission-Line-Resonator Filter,” IRE Trans. Microwave Theory Tech., vol. 6, pp. 223-231, April 1958.
[2.7] G. L. Matthaei, L. Young, and E. M. T. Jones, Microwave Filters, Impedance-Matching Networks, and Coupling Structures, Norwood, MA: Artech House, 1980, ch10, pp. 585-604.
[2.8] G. L. Matthaei, L. Young, and E. M. T. Jones, Microwave Filters, Impedance-Matching Networks, and Coupling Structures, Norwood, MA: Artech House, 1980, ch10, pp. 632-641.
[2.9] Guillermo Gonzalez, Microwave Transistor Amplifiers Analysis and Design, 2nd ed., NJ: Prentice-Hall, 1997, ch1, pp. 22-26.
[2.10] Da-Chiang Chang and Ching-Wen Hsue, “Design and Implementation of Filters Using Transfer Function in the Z Domain,” IEEE Trans. Microwave Theory Tech., vol. 49 no. 5, pp. 979-985, May 2001.
[2.11] L. -C Tsai, H. -M. Chen and C. -W. Hsue, “Z-Domain Formulations of Equal-Length Coupled-Serial-Shunted Lines and their Applications to Filters,” IEE Proc.-Microw. Antennas Propag., vol. 151, no. 2, pp. 97-103, April 2004.
[2.12] L. -C Tsai, H. -M. Chen and C. -W. Hsue, “Dual-Band Bandpass Filters Using Equal-Length Coupled-Serial-Shunted Lines and Z-Transform Technique,” IEEE Trans. Microwave Theory Tech., vol. 52, no. 4, pp. 1111-1117, April 2004.
[3.1] P. I. Richards, “Resistor-Transmission-Line Circuits,” Proc. IRE, vol. 36, no. 2, pp. 217-220, February 1948.
[3.2] Da-Chiang Chang and Ching-Wen Hsue, “Design and Implementation of Filters Using Transfer Function in the Z Domain,” IEEE Trans. Microwave Theory Tech., vol. 49 no. 5, pp. 979-985, May 2001.
[3.3] L. -C Tsai, H. -M. Chen and C. -W. Hsue, “Dual-Band Bandpass Filters Using Equal-Length Coupled-Serial-Shunted Lines and Z-Transform Technique,” IEEE Trans. Microwave Theory Tech., vol. 52, no. 4, pp. 1111-1117, April 2004.
[3.4] G. L. Matthaei, L. Young, and E. M. T. Jones, Microwave Filters, Impedance-Matching Networks, and Coupling Structures, Norwood, MA: Artech House, 1980, ch4, pp. 217-229.
[3.5] L. -C Tsai, H. -M. Chen and C. -W. Hsue, “Z-Domain Formulations of Equal-Length Coupled-Serial-Shunted Lines and their Applications to Filters,” IEE Proc.-Microw. Antennas Propag., vol. 151, no. 2, pp. 97-103, April 2004.
[3.6] M. C. Honton and R. J. Wenzel, “General theory and design of optimum quarter-wave TEM-Filters,” IEEE trans. Microwave Theory Tech., vol. 13, no. 3, pp. 316-327, May 1965.
[3.7] G. L. Matthaei, L. Young, and E. M. T. Jones, Microwave Filters, Impedance-Matching Networks, and Coupling Structures, Norwood, MA: Artech House, 1980, ch4, pp. 83-130.
[3.8] Gabor C. Temes and Sanjit K. Mitra, Modern Filter Theory and Design, New York: John Wiley & Sons, 1973, ch7, pp. 276-277.
[3.9] Max W. Medley, Microwave and RF Circuits: Analysis, Synthesis and Design, Norwood, MA: Artech House, 1993, ch5, pp. 334-340.
[4.1] G. L. Matthaei, “Design of Wide-Band (and Narrow-Band) Band-Pass Microwave Filters on the Insertion Loss Basis,” IEEE Trans. Microwave Theory Tech., vol. 8, no. 6, pp. 580-593, November 1960.
[4.2] 蔡林憲, 使用耦合、串接、並接微帶線及Z-轉換技術合成濾波器, 國立台灣科技大學電子工程系博士學位論文, 中華民國九十三年六月.
[4.3] K.C. Gupta, Ramesh Carg, Inder Bahl, Prakash Bhartia, Microstrip Lines and Slotlines,2nd ed. Norwood, MA: Artech House, 1996, ch3, pp. 180-183.
[4.4] G. L. Matthaei, L. Young, and E. M. T. Jones, Microwave Filters, Impedance-Matching Networks, and Coupling Structures, Norwood, MA: Artech House, 1980, ch4, pp. 83-130.