A method of plasma density measurement based on microwave resonant cavity perturbation (Kornegay ) is described. Resonant cavity theory was analyzed and a resonant cavity with special structure was designed for measuring the low density plasma. In the middle of the closed cavity, there were cut-off tubes which were extended a little into the cavity to get through the plasma. It was found that the distribution of the electrical field intensity was the densest near the cut-off tubes when the cylindrical cavity operating with TM010 mode. By using the method of resonant equivalent circuit analysis, both the amplitudes and phases of the Scattering matrices (S matrices) were obtained before the plasma came and at the time of the plasma passing through. Then the electron line density (Ne) and the electron-molecule collision frequency for momentum transfer (vm) were calculated. A modified formula was proposed based on our simulation which was conducted in HFSS and experimental results. With the comparison of our results and Kornegay's, it was found that the accuracy of the plasma dielectric constant calculation was improved about 5 percent.
2. Wilson, L. N., "The far wake behavior of hypersonic cones," AIAA J., Vol. 5, No. 8, 1393-1396, 1967.
3. Vidmar, R. J., "On the use of atmospheric pressure plasma as electromagnetic reflectors and absorbers," IEEE Transactions on Plasma Science, Vol. 18, No. 4, 73, 1990.
4. Burkley, C. J. and M. C. Sexton, "Measurement of plasma electron distributions using microwave cavities," J. Appl. Phys., Vol. 39, 5013, 1968.
5. Persson, K. B. and E. G. Johnson, "The errors in plasma measurements by the microwave cavity techniques," , Technical Note 607, 1971.
6. Chang, C. H., et al., "A transmission-line microwave interferometer for plasma electron density measurement," Plasma Sources Sci. Technol., Vol. 16, 67, 2007.
7. Laroussi, M. and R. J. Vidmar, "Numerical calculation of the reflection absorption and transmission of microwaves by a nonuniform plasma," IEEE Transactions on Plasma Science, Vol. 2, No. 3, 731-741, 1990.
8. Gibsonw, E. and P. V. Marrone, "A similitude for non-equilibrium phenomena in hypersonic flight," AGARD Meeting on High Temperature Aspects of Hypersonic Fluid Dynamics, 105-131, Brussels, Belgium, Apr. 1962.
9. Rybak, J. P. and R. J. Churchill, "Progress in reentry communications," IEEE Transaction on Aerospace and Electronic Systems, Vol. AES-7, No. 5, 879-894, 1971.
10. Heald, M. A. and C. B. Wharton, Plasma Diagnostics with Microwaves, John Wiley and Sons Inc., New York; London; Sydney, 1965.
11. Charles, J. and C. Brown, "Plasma diagnostics," , Technical Report, 454, Aug. 15, 1966.
12. Spitzer, L., Physics of Fully Ionizes Gases, 2nd Edition, Inter Science, New York, 1967.
13. Buchsbaum, S. J., L. Mower, and S. C. Brown, "Interaction between cold plasmas and guided electromagnetic waves," Phys. Fluids, Vol. 3, No. 5, 806-819, 1960.
14. Kornegay, W. M., "Resonant cavity measurements of ionized wakes," IEEE Transactions on Aerospace and Electronic Systems, Vol. 4, No. 2, 181-186, May 1968.
15. Laroussi, M. and J. R. Roth, "Numerical calculation of the reflection absorption, and transmission of microwaves by a nonuniform plasma slab," IEEE Transactions on Plasma Science, Vol. 2, No. 4, 36, 1993.
16. Leich, M., "All optical tree network for interference-free distance multiplexing," Electronics Letters, Vol. 31, No. 22, 19-32, Oct. 26, 1995.
17. Wan, K.-W. and J. Austin, "A novel approach to the simultaneous of phase and amplitude noise of oscillators," IEEE Transactions on Instrumentation and Measurement, Vol. 40, No. 3, 140-144, 1991.
18. Tuovinen, J., T. M. Hirvonen, and A. V. Raisanen, "Near-field analysis of a thick lens and horn combination: Theory and Measurements," IEEE Trans. Ant. Prop., Vol. 40, No. 6, 613-619, Jun. 1992.
19. Hayami, R., et al., "Open microwave resonators for ionized wake measurement," IEEE Transactions on Aerospace and Electronic Systems, Vol. 3, No. 2, 339-348, Mar. 1967.
20. Ikeda, M., T. Fukunaga, and T. Miura, "Influence of sample inser-tion hole on resonant cavity perturbation measurement method," 2003 IEEE MTT-S International Microwave Symposium Digest, Vol. 2, 1423-1426, 2003.
21. Po, H. T., H. Kawada, and Y. Kohayashi, "Permittivity measurement of dielectric rod samples using a TM010 mode circular cavity," Proc. 2001, Electron. Soc. Conf. of IEICE, C-2-75, 2001 (in Japanese).