Analysis of TE(z)-Mode Cluster in a Stacked Dielectric Resonator Antenna and Its Bandwidth Diversity Application

A novel stacked dielectric resonator antenna (DRA) using the higher order TE(
$\textit {z}$
)-mode cluster to realize bandwidth diversity is reported for the first time. A significant difference in the permittivity between the upside and downside content is the essential condition for higher order TE(
$\textit {z}$
) modes excitation and manipulation. The fundamental TE111(
$y$
) mode generated from the whole mass, as well as three higher order TE
$_{1\alpha 1}$
(
$y$
) (
$\alpha $
= 2, 4, and 6) modes generated from the upside content, is excited simultaneously, resulting in a flexible bandwidth performance. The four modes are verified and analyzed through theoretical calculation. Further parametric study reveals their unique manipulation for giving a desired bandwidth. To demonstrate our proposal, one of the wideband prototypes is fabricated with the upside and downside materials chosen as water and K9 glass, respectively. The DRA is differential-fed by a pair of L-shaped strips. The measured results show that a broadside radiation pattern with a maximum gain of 8.82 dBi can be achieved over a wide bandwidth of 65.4% from 1.75 to 3.45 GHz.