Anritsu HFE0702_Brady 电路图.pdf
22High Frequency Electronics High Frequency Design MICROSTRIP CIRCUITS The Design, Fabrication and Measurement of Microstrip Filter and Coupler Circuits By Dana Brady CAP Wireless, Inc. T odays microwave designers rely on many tools to help create effective circuits and systems. They use their libraries of pub- lished references, along with powerful EDA design tools and electro- magnetic (EM) analysis tools, combined with the lessons of their own experience. Their work is verified with the construction and testing of a finished circuit. This article describes two microstrip designs that were developed using different methods, fabricated quickly using a p.c. board milling machine, then measured to determine the accuracy of the design methods. The example designs are a classic hairpin filter with a bandwidth of 3.7 to 4.2 GHz, and a 1 to 8 GHz directional coupler using the Schiffman sawtooth, or zig-zag, technique to reduce the size. The hairpin filter was designed and simulated using Agilent ADS 1.3 1, with planar EM analysis using Sonnet Lite 2. The coupler used a design-rule-based transformation, starting from an existing stepped-line coupler design. Both circuits were fabricated on a Protomat C100HF from LPKF Laser informa- tion at 2. Sonnet Software; information at: 3. LPKF Laser infor- mation at: 4. Sener Uysal, Nonuniform Line Microstrip Directional Couplers and Filters, Artech House, 1993. Additional Design References 5. G. Matthei, L. Young, E.M.T. Jones, Microwave Filters,Impedance- Matching Networks, and Coupling Structures, Artech House, ISBN 0- 89006-099-1. 6.J.A.G.Mahlerbe,Microwave Transmission Line Filters, Artech House, ISBN 0-89006-063-0. About the Author Dana Brady is Senior Engineer at CAP Wireless,Camarillo,CA. Previously,he has held Senior Engineer positions at California Amplifier, Armatek and Amplica, and the Chief Scientist position at JCA Technology. He attended California Polytechnic State University and has experience in the design of many RF and microwave circuits and systems, including various microprocessor- controlled microwave subsystems. He can be reached by e-mail at: danab Figure 14 Photo of the 3.7 to 4.2 GHz hairpin filter proto- type board. Figure 15 Photo of the 1 to 8 GHz broadband coupler using the Schiffman, or zig-zag line, technique. To submit a technical article for our consideration, simply e-mail a brief description to: Author guidelines can be found on our web site:
