Vertical Transition Shielding via Isolating Slot
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Solution Overview
Problem
Vertical transitions in multilayer printed circuit boards (PCBs) experience high leakage losses and poor shielding properties at higher frequencies due to resonances with parallel-plate modes, which degrade electrical performance.
Innovation Solution
Incorporating a closed ground stripline and an isolating slot around the signal via, with a clearance hole filled by a material having different constitutive parameters than the PCB isolating material, to reduce resonance influences and improve shielding and electrical performance across a wide frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ground vias are used to improve shielding properties, then shielding properties improve, but leakage loss increases due to parallel-plate mode resonances
Solution Approach 1:
An isolating slot is introduced as an intermediary element between the ground vias and the signal via. This slot acts as a mediator that prevents the excitation of parallel-plate modes while maintaining the shielding effect of the ground vias, thereby reducing leakage loss without compromising shielding properties.
Solution Approach 2:
The ground via structure is segmented by introducing an isolating slot that divides the continuous ground plane into separate regions. This segmentation prevents the formation of resonant parallel-plate modes between adjacent ground planes, reducing energy leakage while preserving the local shielding effect around the signal via.
2Loss of energy
If ground via fence is used to reduce leakage loss, then leakage loss decreases, but device complexity increases due to additional structures
Solution Approach 1:
Instead of implementing a complex ground via fence with multiple ground vias surrounding the signal via, the invention uses a simple isolating slot that segments the ground plane. This single slot structure achieves leakage reduction with minimal added complexity compared to multiple ground vias.
Solution Approach 2:
The isolating slot acts as a simple intermediary element that provides the necessary leakage suppression without requiring the complex ground via fence structure. This mediator approach achieves the same functional result with significantly reduced structural complexity.
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
This configuration significantly reduces resonance effects, enhancing the electrical performance and shielding properties of vertical transitions in multilayer PCBs by controlling characteristic impedance and minimizing return losses across a wide frequency range.
Implementation Method 1
parallel-plate modes can excite between conductor planes including space between power supply and ground layers... The parallel-plate modes (PPMs) can resonate with via structures
Implementation Method 2
The electric field of the TEM mode is normal to the planes (in the x direction) so that the associated magnetic field is parallel to the planes (in the y direction)
Implementation Method 3
ground vias surrounding a signal via can be used... ground vias 102 passing through the ground planes are electrically connected to these planes
Data Source
AI summary
Provided are vertical transitions which have the high electrical performance and the high shielding properties in the wide frequency band in a multilayer PCB, printed circuit boards with the vertical transitions and semiconductor packages with the printed circuit boards and semiconductor chips. In vertical transitions for a multilayer PCB, a wave guiding channel is a conductor which includes at least more than one of signal vias 201, an assembly of ground vias 202 surrounding the signal via, ground plates from conductor layers of the PCB connected to the ground vias, closed ground striplines 205 connecting the ground vias and power supply layer.