Theoretical and experimental investigations on rectangular dielectric resonator antennas having a value of /spl epsiv//sub r/, in the range of 10 to 100 are reported. The resonant frequencies and radiation Q-factors of the lowest order "magnetic-dipole" modes are derived on the basis of a first-order theory. The accuracy of the model in predicting the resonant frequency and radiation Q-factor is verified by comparison with results of a rigorous theory and experiments. Various feeds for the antennas such as probe, microstrip slot, and microstrip line are described. Measured radiation patterns are shown and the effect of feed and mode degeneracy on the cross-polarisation levels is discussed.

Theoretical and experimental investigations on rectangular dielectric resonator antennas

This article presents a historical review of the research carried out on dielectric resonator antennas (DRAs) over the last three decades. Major research activities in each decade are highlighted. The current state of the art of dielectric-resonator-antenna technology is then reviewed. The achievable performance of dielectric resonator antennas designed for compactness, wide impedance bandwidth, low profiles, circular polarization, or high gain are illustrated. The latest developments in dielectric-resonator-antenna arrays and fabrication techniques are also examined.

Dielectric Resonator Antennas: A Historical Review and the Current State of the Art

This paper features some of the advances in dielectric-resonator antenna technology at the Communications Research Centre. Several novel elements are presented that offer significant enhancements to parameters such as impedance bandwidth, circular-polarization bandwidth, gain, or coupling to various feed structures. Several linear and planar arrays are also presented, to illustrate the performance of dielectric-resonator antenna elements in the array environment.

Recent advances in dielectric-resonator antenna technology

An apparatus for transmitting power wirelessly is provided. The apparatus comprises: a dielectric resonator which generates evanescent waves in a predetermined direction in order to transmit power; and a loop antenna which is coupled to a surface of the dielectric resonator and supplies power to the dielectric resonator. The dielectric resonator transmits power by means of evanescent waves generated in directions perpendicular to top and bottom surfaces of the dielectric resonator and by radiation in directions parallel to the top and bottom surfaces of the dielectric resonator. Accordingly, efficient power transmission over short and long distance ranges is possible.

Apparatus and system for transmitting power wirelessly

The present invention provides a dielectric resonator antenna comprising: a dielectric resonator; a ground plane, operatively coupled with the dielectric resonator, the ground plane having four slots; and a substrate, operatively coupled to the ground plane, having a feeding network consisting of four microstrip lines; wherein the four slots are constructed and geometrically arranged to ensure proper circular polarization and coupling to the dielectric resonator; and wherein the antenna feeding network combines the four microstrip lines with a 90 degree phase difference to generate circular polarization over a wide frequency band.

Wideband circularly polarized hybrid dielectric resonator antenna

Open dielectric resonators (DRs) have been increasingly studied as antenna elements in recent years. They offer advantages such as small size, mechanical simplicity, no conduction loss, easy coupling to most transmission lines, ability to obtain different radiation characteristics using different modes of the DR, etc. Further, desired impedance bandwidth (in the range of about 1%-20%) can be obtained by the suitable choice of DR shape and permittivity. Of various possible shapes, a rectangular shaped DR antenna (DRA) provides advantages over other shapes, such as cylindrical and spherical. It is known that three TE/sub 111/ modes (TE/sub 111//sup x/,TE/sub 111//sup y/ and TE/sub 111//sup z/) of a rectangular shaped DRA radiate like x, y and z directed magnetic dipoles respectively. Given the advantages of DRAs, a circularly polarized (CP) element may provide useful benefits over other existing designs. In this paper, we report the development of a new rectangular CP DRA with a single slot or probe feed. The circular polarization is obtained by the excitation of two nearly degenerate orthogonal magnetic dipole modes. Measured results show that the antenna has a low axial ratio (AR) over a wide frequency band and has a wide beamwidth. The antenna element is easy to design and construct, and the dimensional tolerances are not stringent. The slot fed antenna is also compatible with MIC's and MMIC's and should be therefore useful in high frequency applications. Theoretical development, design and experimental results on DRAs of various permittivities (/spl epsiv//sub r/=10.8, 20 and 40) with both slot and probe feed are presented.

R.K. Mongia

Papers

A new broadband circularly polarized dielectric resonator antenna