3-D Transmitting Pattern Manipulation Structures Using Slotline Bandpass Filter Elements: Synthetic Design and Implementation

This article proposes a novel design concept of 3-D transmitting pattern manipulation structures (PMSs) using slotline bandpass filter (BPF) elements. First, the parallel-coupled slotline is utilized to synthetically design a slotline element by employing the equivalent transmission line model. Then, two types of elements are designed to implement the proposed PMS. The element-I with a variable transmission phase is realized by adjusting the resonant frequency of slotline structure, while keeping the transmission magnitude almost equal to 0 dB within an operating bandwidth of 13.2%. The element-II is obtained by connecting two element-Is in series for a larger range of transmission phase with an operating bandwidth of 10.3%. After that, two 3-D transmitting PMSs (PMS-I with
$8\times20$
elements and PMS-II with
$10\times30$
elements) are obtained by quasi-periodically arranging element-I and element-II, respectively. Finally, two prototypes of PMS-I and PMS-II are fabricated and tested to validate our design concept. Measurements and simulations agree well with each other, showing the desired transmission angles of (
$\theta _{I}=10^{\circ }$
and
$\phi _{I}$
= 90°) for PMS-I and (
$\theta _{II}=20^{\circ }$
and
$\phi _{II}$
= 90°) for PMS-II with the highest efficiencies of 92.8% and 88.9%. Therefore, the proposed 3-D transmitting PMS can be evidently used as a promising candidate to form the transmission waves for the future smart radio environment.