A novel 3D two-ways folded microstrip line and its application in super-miniaturized microwave wireless components

Abstract

A novel 3D folded two-ways microstrip lines (MLs) are proposed for realizing the super-miniaturization of electron devices. The 3D structure realized with two-ways folded MLs, which consists of several groups of cross-connected MLs and conductive vias, has the potential to have an advanced performance than the corresponding conventional, meandering and 3D one-way MLs. Longer MLs can be arranged in limited space. The superficial area of the 3D folded structure is significantly smaller than those proposed MLs in similar return loss. The methodology is validated with the design of single band, reduced size Wilkinson power divider (WPD), and branch-line hybrid coupler (BLHC) at 433 MHz. Reduction of the transmission line segments is from λ/4 to λ/32. The physical sizes have been reduced by 98.15 and 95.54%, compared with the conventional WPD and BLHC. This paper summarizes the longest 50 Ω MLs in a particular size and gets the conclusion that the structure could be used more effectively in the lower working frequency.