volume | PIER Journals

2005-08-23

Analysis of Transmission of a Signal through a Complex Cylindrical/Coaxial Cavity by Transmission Line Methods

Charles Bopp III,

Mr. Charles Bopp III

Holcombe Department of Electrical and Computer Engineering

Clemson University

USA

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Chalmers Butler

Dr. Chalmers Butler

Department of Electrical and Computer Engineering

Clemson University

USA

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, Vol. 56, 33-51, 2006

doi:10.2528/PIER05041403

Abstract

The transmission of time-harmonic and transient signals through a complex cylindrical cavity is investigated by methods akin to microwave circuit techniques. The cavity may consist of multiple overlapping cascaded coaxial and circular cylindrical sections whose walls are perfect electric conductors. The sections may have different axial and radial dimensions and may be filled with material having different magnetic and electric properties. The first and last sections of the cavity are coaxial regions where only TEM modes exist, which allows measurements to be performed with proper excitation and termination. The cavity sections may support both a TEM mode and additional higher order modes or may support one or the other. If two sections have a common junction and each supports only one mode, then the junction is modeled by a simple two-port network. When additional modes are present, they are modeled by addition ports at the network junction. Corresponding equivalent transmission lines are associated with each mode at a physical junction. At each junction, scattering parameters are calculated and used to model the interaction of the various modes that exist. The S-parameters at each junction are determined separately by solving a simple integral equation that accounts for the structure of the junction and adjoining sections of coaxial and/or cylindrical guide. The cavity fields are, thus, associated with equivalent currents and voltages on transmission lines. A transmission line network is developed from which the input fields, fields at the cavity termination, and junction fields can be found by microwave circuit techniques or by the BLT transmission line analysis. The results from the transmission line method are compared with results calculated from a coupled integral equation analysis which has been carefully validated experimentally and with measured values on laboratory models.

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Charles Bopp III, and Chalmers Butler, "Analysis of Transmission of a Signal through a Complex Cylindrical/Coaxial Cavity by Transmission Line Methods," , Vol. 56, 33-51, 2006.
doi:10.2528/PIER05041403

References

1. Baum, C. E., T. K. Liu, and F. M. Tesche, "On the analysis of general multiconductor transmission line networks," Interaction Note 350, 1978.

2. Bopp, III, L. Charles, and C. M. Butler, "Field in a complex cylindrical/coaxial cavity sub ject to time-harmonic and transient excitation," accepted by Radio Science, No. 8, 2004.

3. Collin, R. E., Field Theory of Guided Waves, McGraw-Hill, New York, 1960.

4. Hall, R. C., R. Mittra, and K. M. Mitzner, "Analysis of multilayered periodic structures using generalized scattering matrix theory," IEEE Trans. on Antennas Prop., Vol. 36, No. 4, 511-517, 1988.
doi:10.1109/8.1140

5. Haskal, H., "Matrix description of waveguide discontinuities in the presence of evanescent modes," IEEE Trans. Microwave Theory Tech., No. 3, 184-188, 1964.
doi:10.1109/TMTT.1964.1125782

6. Kahn, W. K. and H. Kurss, "Minimum scattering antennas," IEEE Trans. on Antennas Prop., No. 9, 671-675, 1965.
doi:10.1109/TAP.1965.1138529

7. Kerns, D. M., "Basis of application of network equations to waveguide problems," J. Res. NBS, No. 5, 515-540, 1949.

8. Kerns, D. M., Plane-Wave Scattering-Matrix Theory of Antennas and Antenna-Antenna Interactions, U.S. Government Printing Office, Washington, DC, 1981.

9. Lee, W., G. Zarrillo, and C. L. Law, "Simple formulas for transmission through periodic metal grids or plates," IEEE Trans. on Antennas Prop., Vol. 33, No. 9, 1009-1011, 1985.
doi:10.1109/TAP.1985.1143706

10. Ling, H., "RCS of waveguide cavities: a hybrid boundary-integral/modal approach," IEEE Trans. on Antennas Prop., Vol. 38, No. 9, 1413-1420, 1990.
doi:10.1109/8.56993

11. Mittra, R. and S. W. Lee, Analytical Techniques in the Theory of Guided Waves, Macmillan, New York, 1971.

12. Montgomery, C. G., Principles of Microwave Circuits, Office of Scientific Research and Development, NDRC, McGraw-Hill Book Co., New York, 1948.

13. Young, J. C., C. M. Butler, and C. L. Bopp, III, "Transient signals in coupled coaxial and cylindrical cavities," Digest of 2002 USNC/URSI National Radio Science Meeting, No. 6, 2002.