Quasi-Degenerated Modes in High-ε Dielectric Cavities

Abstract

This paper deals with resonance effects in circularly cylindrical solid bodies of high-ε dielectrics such as titanates, these bodies being either not metallized or partly or fully metallized by fired-on silver. The high dielectric constant has two pronounced effects: (a) Miniaturization, a linear reduction in size in the order of magnitude of 1/100, and (b) Realization of boundary conditions approaching infinite wave impedance. All four combinations of radial and axial wave impedance being zero (metallized) or infinite (interface dielectric/air) are investigated mathematically and experimentally. Special consideration is given to degenerated modes; that is, modes for which the axial dimensions of the cavity do not contribute to the resonance wavelength. Because of the inherent magnetic leakage through the dielectric, this is only conditionally true. These modes are therefore termed quasi-degenerated. In contrast to conventional cavity theory dealing only with metallic boundaries, quasi-degenerated TE modes are realizable; namely, if the faces of the cylindrical cavities are not metallized. These cavities can be tuned by introducing magnetic rods into them or by application of conductive disks outside of them in the proper position. A novel type of antenna can be evolved from the TE010∞∞ mode, comprising a dielectric spiral encircling a magnetic rod. In many cases the relatively high temperature coefficient, dissipation factor, and noise level prevent for the time being the potential application of these high-ε dielectrics.

Excitation of Enhanced Hybrid Cylindrical Dielectric Resonator Antenna to be used for Wireless Applications

“…The concept of the (DRA) was firstly exploited in 1938 and been used as a device for energy storage [1]. A few years later and in 1953, Schlike has come up with the fact that there are such materials with high permittivity εr greater than 1000 exists [2]. A decade ahead Okaya and Barash carried out research to study the TExyz and TMxyz modes propagation and distribution within the dielectric slab [3].…”

“…Both the resonant frequencies and the size are directly related and considered by the following;The slot length is equivalent to: fr presents the resonant frequency, and the active relative constant within the slot εre can be expressed by:εrs presents the relative permittivity of the substrate. Uisng both (1),(2) and(3), this can predict:…”

Four Identical Elements Triangular Dielectric Resonator Antenna with L-shaped Coaxial Feed for wireless applications

“…The dielectric resonators were firstly (in 1939) exploited for the realization of energy storage devices [1]. By the production of high permittivity materials in 1953 [2], these structures earned their place for the antenna applications. Since the early sixties, the field distribution of the TMxyz and TExyz modes and the propagations have been studied [3].…”

External Q of loop coupled dielectric resonator

“…To date, works have been reported on the resonant frequency, resonant modes, the effect of the metal wall on the resonator loss and the measurement of dielectric materials [2][3][4][5][6], as well as on the filters made of dielectric resonators [7][8][9][10][11]. In the case of designing filters and resonators for frequency-stabilized oscillators, it is necessary to know the external Q of the resonator.…”