Analysis of TE(<i>z</i>)-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(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(z) modes excitation and manipulation. The fundamental TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">111</sub> (y) mode generated from the whole mass, as well as three higher-order TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1α1</sub> (y) (α=2,4,6) modes generated from the upside content, are 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 8.82dBi can be achieved over a wide bandwidth of 65.4% from 1.75 GHz to 3.45 GHz.