volume | PIER Journals

2006-11-19

Generalized Equivalent Circuit Model for Transverse Waveguide Slots and Applications

Islam Eshrah,

Prof. Islam Eshrah

Department of Electronics and Communications

Cairo University

Egypt

Homepage

Ahmed Kishk,

Professor Ahmed Kishk

Department of Electrical Engineering

University of Mississippi

USA

Homepage

Alexander Yakovlev,

Professor Alexander Yakovlev

Department of Electrical Engineering

The University of Mississippi

USA

Homepage

Allen Wilburn Glisson

Dr. Allen Wilburn Glisson

Department of Electrical Engineering

The University of Mississippi

USA

Homepage

, Vol. 69, 1-20, 2007

doi:10.2528/PIER06110803

Abstract

A generalized equivalent circuit model for waveguide transverse slots is proposed for the efficient analysis of waveguide transitions and waveguide slot antennas and slot-excited antennas. The transverse slots on the broad and end waveguide walls analyzed in this paper are decomposed into three structures: two apertures and an auxiliary waveguide section. The slot aperture in the host waveguide is modeled as an inductance-capacitance-transformer (LCT) combination, for which the equivalent inductance and capacitance are determined by first considering the case of zero-thickness slot, then the transformer turns ratio is calculated for the slot on a finite thickness wall. The effect of the wall thickness is accounted for by a waveguide section having cross-sectional dimensions equal to those of the slot, and length equal to the wall thickness. The loaded slot aperture is modeled along with the external load as a lumped load impedance. Expressions for the inductance, capacitance and transformer turns ratio are obtained in terms of the slot length and width. The obtained expressions facilitate the design of a variety of structures, including waveguide couplers, feeding networks and radiators. The equivalent circuit model proved to be accurate compared to the method of moments solution over a wide frequency band. Comparison of the scattering parameters obtained from the circuit analysis, the method of moments, and the finite-difference time-domain solutions exhibit very good agreement.

Citation

Copy Export

Islam Eshrah, Ahmed Kishk, Alexander Yakovlev, and Allen Wilburn Glisson, "Generalized Equivalent Circuit Model for Transverse Waveguide Slots and Applications," , Vol. 69, 1-20, 2007.
doi:10.2528/PIER06110803

References

1. User's Guide Advanced Design System 2003A, Agilent Techn., 2003.

2. Elliott, R. S., Antenna Theory and Design, Prentice-Hall, Englewood Cliffs, NJ, 1981.

3. Elliott, R. S. and W. R. O'Loughlin, "The design of slot arrays including internal mutual coupling," IEEE Trans. Antennas Propag., Vol. 34, No. 9, 1149-1154, 1986.
doi:10.1109/TAP.1986.1143947

4. Casula, G. A. and G. Mazzarella, "A direct computation of the frequency response of planar waveguide slot arrays," IEEE Trans. Antennas Propag., Vol. 52, No. 7, 1909-1912, 2004.
doi:10.1109/TAP.2004.830253

5. Mazzarella, G. and G. Montisci, "Wideband equivalent circuit of a centered-inclined waveguide slot coupler," J. Electromagn. Waves Applicat., Vol. 14, 133-151, 2000.

6. Yee, H. Y., "The design of large waveguide arrays of shunt slots," IEEE Trans. Antennas Propag., Vol. 40, No. 7, 775-781, 1992.
doi:10.1109/8.155742

7. Stegen, R. J., "Slot radiators and arrays at X-band," IEEE Trans. Antennas Propag., Vol. 1, No. 2, 62-64, 1952.

8. Elliott, R. S., "An improved design procedure for small arrays of shunt slots," IEEE Trans. Antennas Propag., Vol. 31, No. 1, 48-53, 1983.
doi:10.1109/TAP.1983.1143002

9. Eshrah, I. A., A. A. Kishk, A. B. Yakovlev, and A. W. Glisson, "Theory and implementation of dielectric resonator antenna excited by waveguide slot," IEEE Trans. Antennas Propag., Vol. 53, No. 1, 483-494, 2005.
doi:10.1109/TAP.2004.838782

10. Eshrah, I. A.A. A. Kishk, A. B. Yakovlev, and A. W. Glisson, "Load-independent equivalent circuit model for transverse waveguide slots," Proc. IEEE AP-S Int. Symp., No. 7, 2005.

11. Eshrah, I. A., A. A. Kishk, A. B. Yakovlev, A. W. Glisson, and C. E. Smith, "Analysis of waveguide slot-based structures using wideband equivalent circuit model," IEEE Trans. Microwave Theory Tech., Vol. 52, No. 12, 2691-2696, 2004.
doi:10.1109/TMTT.2004.837320

12. QuickWave3D: A general purpose electromagnetic simulator based on conformal finite-difference time-domain method v.2.2, 1998.