ANALYSIS OF A BROAD-BAND SLOT-COUPLED DIELECTRIC-COATED HEMISPHERICALDIELECTRIC RESONATOR ANTENNA

Dielectric-coated hemispherical dielectric resonator (DR) antennas fed by a microstrip line through a coupling slot are analyzed. The broads ide TE111 mode is studied, and the reciprocity theorem is applied in t his analysis. In this case the dielectric-coated DR antenna can be vie wed as a series load at the slot position as seen by the microstrip li ne. The impedance of this series load is calculated by using a Green's -function formulation, and the input impedance of the slot-coupled DR antenna can then be obtained using transmission-line theory. Numerical results for the input impedance are calculated and presented, and the antenna bandwidth is discussed. It is observed that the antenna bandw idth of a dielectric-coated DR antenna can be as high as two times tha t of a DR antenna without a coating. (C) 1995 John Wiley & Sons, Inc.