Forced Resonant Type Cutoff Cavity-Backed Aperture Antennas Loaded with a Single External Reactance

  • Kim Ki-Chai (Department of Electrical Engineering, College of Engineering, Yeungnam University) ;
  • Hirasawa Kazuhiro (Institute of Information Sciences and Electronics, University of Tsukuba)
  • Published : 2005.09.01


This paper presents the basic characteristics of a cutoff cavity-backed aperture antenna with a feed post and a parasitic post inserted parallel to the aperture. It is shown that this type of antenna forcibly resonates the cutoff cavity by adding a single external reactance to the parasitic post. The Galerkin's method of moments is used to analyze integral equations for the unknown electric current on each post and the aperture electric field on the aperture. The value of an external reactance for forced resonance is analytically obtained by deriving a determining equation. Also the current distribution on each post, aperture electric field distributions, and the radiation patterns are discussed. The theoretical analysis is verified by the measured return loss and radiation patterns.


  1. A. T. Adams, 'Flush mounted rectangular cavity slot antennas- Theory and design', IEEE Trans. Antennas Propagat., vol. 15, pp. 342-351, May 1967
  2. M. Omiya, T. Hikage, N. Ohno, K. Horiguchi, and K. Itoh, 'Design of cavity-backed slot antennas using the finite-difference time-domain technique', IEEE Trans. Antennas Propagat., vol. 46, pp. 1853-1858, Dec. 1998
  3. R. F. Harrington, Field Computation by Moment Methods, Macmillan, New York, 1968
  4. J. Galejs, 'Admittance of a rectangular slot which is backed by a rectangular cavity', IEEE Trans. Antennas Propagat., vol. 11, pp. 119-126, Mar. 1963
  5. T. Hikage, N. Ohno, M. Omiya, and K. Itoh, 'Proposal of cavity-backed slot antennas for the microwave energy transmission', IEICE Trans., vol. J81B-II, pp. 218-225, Mar. 1998
  6. R. E. Collin, Field Theory of Guided Waves, McGraw-Hill, Chap. 5, New York, 1960
  7. H. Morishita, K. Hirasawa, and K. Fujimoto, 'Analysis of a cavity-backed annular slot antenna with one point shorted', IEEE Trans. Antennas Propagat., vol. 39, pp. 1472-1478, Oct. 1991
  8. J. Hirakawa, H. Arai, and N. Goto, 'Cavity-backed wide slot antenna', Proc. Inst. Elect. Eng., vol. 136, pt. H, pp. 29-33, Feb. 1989
  9. K. C. Kim, S. Tokumaru, 'A cutoff cavity antenna having resonant posts', IEICE Trans., vol. J70-B, pp. 1217-1228, Oct. 1987
  10. K. C. Kim, I. S. Kwon, 'Beam tilting dipole antenna elements with forced resonance by reactance loading', IEICE Trans. Commun., vol. E83-B, pp. 77-83, Jan. 2000