Departmental Papers (ESE)


We suggest an idea for miniaturization of cavities by utilizing a properly designed metamaterial thin surface inserted inside the cavities. This metamaterial surface is constituted by a thin dielectric slab on both sides of which “gangbuster” dipoles are printed. Inserting the thin slab inside a parallel-plate one-dimensional (1-D) cavity resonator has the effect of decreasing the resonant frequency. Placing the metamaterial slab at the center of a rectangular waveguide also lowers the cut-off frequency of the dominant mode of the waveguide. The corresponding dispersion curve exhibits a smooth transition from a fast-wave to a slow-wave regime and then asymptotically tends to the dispersion curve of the first TE surface-wave mode of the metamaterial slab. This suggests a natural way to conceive a 3-D compact cavity resonator by placing two perfectly electric conducting walls, a half of the wavelength of the slow-wave mode apart, inside the above rectangular waveguide. The analysis, performed by a circuit network theory and validated by a full-wave numerical analysis, provides simple formulas to predict the resonant frequency and the dispersion diagrams of these structures.

Document Type

Journal Article

Date of this Version



Copyright 2004 IEEE. Reprinted from IEEE Antennas and Wireless Propagation Letters, Volume 3, Issue 1, December 2004, pages 261-264. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to By choosing to view this document, you agree to all provisions of the copyright laws protecting it.


Electromagnetic bandgap structures, frequency selective surfaces, metamaterials, periodic surfaces, resonators, transmission line networks, waveguides



Date Posted: 17 May 2006

This document has been peer reviewed.