Miniaturization of a wideband magnetoelectric dipole antenna by folding

Abstract

In this Letter, we investigate a wideband magnetoelectric dipole antenna miniaturized by folding. In the proposed design, a folded L‐shaped electric dipole is used instead of the conventional half‐wavelength horizontal electric dipole, and a pair of vertically folded shorted patches act as a magnetic dipole, producing a miniaturized radiator. Furthermore, a small‐size U‐shaped reflector replaces the traditional large‐size planar reflector, resulting in a decrease in the low end of the frequency band, while the high end of the frequency band remains almost unchanged. A better impedance matching is also obtained over the entire operating frequency band. Ultimately, a miniaturized overall structure and a wide bandwidth are obtained simultaneously. The overall size of the proposed antenna is only bold-italic0 bold-italic. bold-italic25 λ L bold-italic× bold-italic0 bold-italic. bold-italic25 λ L bold-italic× bold-italic0 bold-italic. bold-italic12 λ L ${\boldsymbol{0}}{\boldsymbol{.}}{\boldsymbol{25}}{{\boldsymbol{\lambda }}}_{{\boldsymbol{L}}}{\boldsymbol{\times }}{\boldsymbol{0}}{\boldsymbol{.}}{\boldsymbol{25}}{{\boldsymbol{\lambda }}}_{{\boldsymbol{L}}}{\boldsymbol{\times }}{\boldsymbol{0}}{\boldsymbol{.}}{\boldsymbol{12}}{{\boldsymbol{\lambda }}}_{{\boldsymbol{L}}}$ (where λ L ${{\boldsymbol{\lambda }}}_{{\boldsymbol{L}}}$ is the longest operating wavelength), which is 82% smaller than the size of the original design, but the proposed antenna can still obtain a large bandwidth of 120% (1–4 GHz) for VSWR < 2. Furthermore, stable radiation patterns are realized with an average gain of 5 dBi within the operating frequency band.

High‐gain miniaturized magnetoelectric dipole antenna array for millimeter‐wave applications

“…The measurement shows that the impedance bandwidth of the antenna is 29%, ranging from 22.4 to 30 GHz, with a mean gain of 8.04 dBi. Although Li et al 6 and Shen et al 7 achieve wide impedance bandwidth, the actual size is large and the gain is low. In this paper, a high-gain miniaturized MED antenna array for mmW applications is proposed.…”

“…However, the actual size of the antenna array is too large, which is not conducive to processing integration. In Li et al, 6 the MED antenna consists of an L‐shaped folded patch as the electric dipole and a pair of vertically folded shorted patches as the magnetic dipole. The manufactured MED antenna has a measured impedance bandwidth that can reach 120% (1–4 GHz) with an average gain of 5 dBi.…”