Multilayer Loop Coupler with Floating Plate for Wideband Performance
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Solution Overview
Problem
Conventional couplers face challenges in achieving wideband performance without becoming excessively long and lossy, especially at higher frequencies, due to the inherent coupling roll-off when the length exceeds one-quarter wavelength, and the tight coupling at the center frequency leads to reduced bandwidth.
Innovation Solution
A multilayer coupler design featuring a ground plane and planar signal conductors that form a closed loop with compensated bends, utilizing a floating-potential plate and openings in the ground plane to maintain balanced coupling and reduce even-mode impedance changes, allowing for a wideband design without increased length or loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the coupler length is increased to achieve wideband performance, then the bandwidth is improved, but the loss increases and the coupler becomes excessively long
Solution Approach 1:
The coupler is divided into multiple coupled sections (first, second, and third coupled sections) with different coupling strengths. The center section has tighter coupling while the outer sections have weaker coupling, allowing the overall structure to achieve wideband performance without requiring excessive length. This segmentation enables each section to contribute differently to the overall bandwidth and coupling characteristics.
Solution Approach 2:
Different sections of the coupler have different coupling characteristics - the center section has tight coupling while the outer sections have weaker coupling. This local variation in coupling quality allows the coupler to maintain manageable length while achieving wideband performance, as each local region is optimized for its specific function.
2Adaptability or versatility
If the coupler length is increased to achieve wideband performance, then the bandwidth is improved, but the coupler becomes excessively long
Solution Approach 1:
The coupler is divided into multiple coupled sections (first, second, and third coupled sections) with different coupling strengths. The center section has tighter coupling while the outer sections have weaker coupling, allowing the overall structure to achieve wideband performance without requiring excessive length. This segmentation enables each section to contribute differently to the overall bandwidth and coupling characteristics.
Solution Approach 2:
Different sections of the coupler have different coupling characteristics - the center section has tight coupling while the outer sections have weaker coupling. This local variation in coupling quality allows the coupler to maintain manageable length while achieving wideband performance, as each local region is optimized for its specific function.
3Reliability
If the coupling is made tighter at the center frequency to improve performance, then the coupling efficiency is improved, but the bandwidth is reduced
Solution Approach 1:
Different sections of the coupler have different coupling characteristics - the center section has tight coupling for high efficiency at the center frequency, while the outer sections have weaker coupling to extend the overall bandwidth. This local differentiation resolves the trade-off between coupling efficiency and bandwidth.
Solution Approach 2:
The coupler is divided into multiple coupled sections (first, second, and third coupled sections) with different coupling strengths. The center section has tighter coupling while the outer sections have weaker coupling, allowing the overall structure to achieve wideband performance without requiring excessive length. This segmentation enables each section to contribute differently to the overall bandwidth and coupling characteristics.
4Area of stationary object
If bends are introduced in the signal conductors to achieve compact layout, then the space utilization is improved, but the coupling balance is disrupted and even-mode impedance changes
Solution Approach 1:
A floating-potential plate is introduced as an intermediary element in the bend region. This plate is electrically isolated from the signal conductors and ground plane, serving as a mediator that maintains the electromagnetic field distribution and coupling balance during the transition through the bend, thereby stabilizing the even-mode impedance.
Solution Approach 2:
The ground plane is removed or created with an opening in the bend region, extracting the ground reference from the problematic area. This allows the floating-potential plate to serve as the effective ground reference for the bending conductors, maintaining coupling balance without the constraints of a continuous ground plane.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The multilayer coupler design achieves improved bandwidth and reduced coupling losses in bends, maintaining balanced coupling throughout the loop, thus extending the bandwidth while keeping the coupler length manageable and minimizing losses.
Implementation Method 1
Two conductive lines are coupled when they are spaced apart, but spaced closely enough together for energy flowing in one to be induced in the other
Implementation Method 2
Parallel transmission lines couple both electrically and magnetically
Implementation Method 3
maintain balanced coupling and reduce even-mode impedance changes
Data Source
AI summary
A multilayer coupler may include electromagnetically coupled planar first and second signal conductors that are separated by a gap, extend adjacent each other along a ground plane, and change orientation in a bend. A plate may be positioned along the bend between the ground plane and the signal conductors. The ground plane may have an opening extending along the bend and the plate. A multilayer coupler may include two coupled signal conductors formed in a loop having a four-wire section in which different sections of the two signal conductors overlap in a four-wire section. In a transition region in which the coupler transitions from the four-wire section to a two-wire section, an isolating ground plane may separate the two two-wire sections extending from the four-wire section. A bend in the transition region may include a plate between the two signal conductors and the ground plane.