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IEEE Transactions on Antennas and Propagation
Volume 47 Number 2, February 1999

Table of Contents for this issue

Complete paper in PDF format

Resonant Frequencies of Rectangular Microstrip Antennas with Flush and Spaced Dielectric Superstrates

Jennifer T. Bernhard, Member, IEEE, and Carolyn J. Tousignant, Student Member, IEEE

Page 302.

Abstract:

This paper presents a predictive model for the resonant frequencies of rectangular microstrip antennas with flush and spaced superstrates. This closed-form model is suitable for CAD and is directly applicable for the integration of microstrip antennas beneath plastic covers or protective dielectric superstrates in portable wireless equipment. The model utilizes conformal mapping and the concept of equivalent capacitance to determine the effective permittivity of a covered microstrip structure. A comparison between calculated and measured resonant frequencies demonstrates that the model provides less than 1% errors for structures with low relative permittivities ({{\varepsilon}}_{{\scriptstyle{r}}} < {{3}}) and slightly higher errors for structures that contain higher permittivity materials. Generally, the model predicts the resonant frequency of a spaced superstrate structure as accurately as possible within the tolerance range of the structure's electrical and physical parameters.

References

  1. I. J. Bahl, P. Bhartia, and S. Stuchly, "Design of microstrip antennas covered with a dielectric layer," IEEE Trans. Antennas Propagat., vol. 30, pp. 314-318, Mar. 1982.
  2. A. K. Verma, A. Bhupal, Z. Rostamy, and G. P. Srivastava, "Analysis of rectangular patch antenna with dielectric cover," IEICE Trans., vol. E74, pp. 1270-1276, May 1991.
  3. R. Shavit, "Dielectric cover effect on rectangular microstrip antenna array," IEEE Trans. Antennas Propagat., vol. 42, pp. 1180-1184, Aug. 1994.
  4. Z. Fan and K. F. Lee, "Input impedance of annular-ring microstrip antenna with a dielectric cover," IEEE Trans. Antennas Propagat., vol. 40, pp. 992-995, Aug. 1992.
  5. A. Verma and Z. Rostamy, "Resonant frequency of uncovered and covered rectangular microstrip patch using modified Wolff model," IEEE Trans. Microwave Theory Tech., vol. 41, pp. 109-116, Jan. 1993.
  6. J. P. Damiano and A. Papiernik, "A simple and accurate model for the resonant frequency and the input impedance of printed antennas," Int. J. Microwave Millimeter-Wave Computer-Aided Eng., vol. 3, pp. 350-361, 1993.
  7. J. P. Damiano, J. M. Rivero, and R. Staraj, "Original simple and accurate model for elliptical microstrip antennas," Electron. Lett., vol. 31, pp. 1023-1024, June 1995.
  8. D. M. Pozar, "Input impedance and mutual coupling of rectangular microstrip antennas," IEEE Trans. Antennas Propagat., vol. 30, pp. 1191-1196, Nov. 1982.
  9. J. R. Mosig and F. E. Gardiol, "General integral equation formulation for microstrip antennas and scatterers," Proc. Inst. Elect. Eng., vol. 132, pt. H, pp. 424-432, Dec. 1985.
  10. K. A. Michalski and D. Zheng, "Analysis of microstrip resonators of arbitrary shape," IEEE Trans. Microwave Theory Tech., vol. 40, pp. 112-119, Jan. 1992.
  11. O. M. Ramahi and Y. T. Lo, "Superstrate effect on the resonant frequency of microstrip antennas," Microwave Opt. Technol. Lett., vol. 5, pp. 254-257, June 1992.
  12. A. Bhattacharyya and T. Tralman, "Effects of dielectric superstrate on patch antennas," Electron. Lett., vol. 24, pp. 356-358, Mar. 1988.
  13. R. Afzalzadeh and R. N. Karekar, "Characteristics of a rectangular microstrip patch antenna with protecting spaced dielectric superstrate," Microwave Opt. Technol. Lett., vol. 7, pp. 62-66, Feb. 1994.
  14. D. M. Pozar, "Microstrip antennas," Proc. IEEE, vol. 80, pp. 79-91, Jan. 1992.
  15. H. A. Wheeler, "Transmission-line properties of parallel strips separated by a dielectric sheet," IEEE Trans. Microwave Theory Tech., vol. 13, pp. 172-185, Mar. 1965.
  16. J. Svacˇina, "Analysis of multilayer microstrip lines by a conformal mapping method," IEEE Trans. Microwave Theory Tech., vol. 40, pp. 769-772, Apr. 1992.
  17. S.-S. Zhong, G. Liu, and G. Qasim, "Closed form expressions for resonant frequency of rectangular patch antennas with multidielectric layers," IEEE Trans. Antennas Propagat., vol. 42, pp. 1360-1363, Sept. 1994.
  18. H. Wheeler, "Transmission-line properties of parallel wide strips by a conformal mapping approximation," IEEE Trans. Microwave Theory Tech., vol. 12, pp. 280-289, Mar. 1964.
  19. M. V. Schneider, "Microstrip lines for microwave integrated circuits," Bell Syst. Tech. J., vol. 48, pp. 1421-1443, May/June 1969.
  20. M. Kirschning, R. H. Jansen, and N. H. L. Koster, "Accurate model for open end effect of microstrip lines," Electron. Lett., vol. 17, pp. 123-125, Feb. 1981.
  21. M. Kirschning and R. H. Jansen, "Accurate model for effective dielectric constant of microstrip with validity up to millimeter-wave frequencies," Electron. Lett., vol. 18, pp. 272-273, Mar. 1982.
  22. S. Ramo, J. R. Whinnery, and T. V. Duzer, Fields and Waves in Communication Electronics, 3rd ed.New York: Wiley, 1994.
  23. S. H. Al-Charchafchi and M. R. Ibrahim, "An experimental investigation of flat radome-loaded microstrip patch antennas," Microwave J., vol. 40, pp. 100-109, Feb. 1997.
  24. R. W. Dearnley and A. R. F. Barel, "A comparison of models to determine the resonant frequencies of a rectangular microstrip antenna," IEEE Trans. Antennas Propagat., vol. 37, pp. 114-118, Jan. 1989.
  25. M. Kara, "Closed-form expressions for the resonant frequency of rectangular microstrip antenna elements with thick substrates," Microwave Opt. Technol. Lett., vol. 12, pp. 131-136, June 1996.
  26. I. J. Bahl and P. Bhartia, Microstrip Antennas.Dedham, MA: Artech House, 1980.
  27. D. M. Pozar, "Rigorous closed-form expressions for the surface wave loss of printed antennas," Electron. Lett., vol. 26, pp. 954-956, June 1990.
  28. M. Kara, "Empirical formulas for the computation of the physical properties of rectangular microstrip antenna elements with thick substrates," Microwave Opt. Technol. Lett., vol. 14, pp. 115-121, Feb. 1997.