Multilayer Filter Layout With Tolerance-Stable Overlap Capacitance

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Solution Overview

Problem

Conventional filter designs using discrete components on printed circuit boards face challenges with space optimization, symmetry, and manufacturing tolerance issues, particularly in achieving low manufacturing tolerances and compact, symmetrical capacitance structures.

Innovation Solution

The design incorporates a filter with an electrical circuit arrangement featuring conductive surfaces on a substrate, where at least one surface is smaller in dimension and overlaps on both sides by a larger surface, maintaining a constant capacitance even with displacement, and includes spatially concentrated inductances and capacitances integrated on a ceramic or dielectric substrate, ensuring symmetry and reduced space usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If discrete components are used on printed circuit boards, then manufacturing accuracy can be achieved, but space requirement increases and symmetry is compromised

Engineering Contradiction:
Improvecomponent toleranceVSAvoidspace requirement
Core Design Contradiction:
Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The patent merges multiple discrete components (capacitors and inductors) into an integrated circuit board structure. Capacitors are formed by conductive surfaces on different layers of the substrate, and inductors are formed by conductor tracks, all integrated within the same substrate structure. This consolidation reduces the overall space requirement while maintaining manufacturing precision through controlled fabrication processes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from two-dimensional discrete component placement on a single plane to three-dimensional integration using multiple layers of the substrate. Conductive surfaces on different layers form capacitors, and conductor tracks on various layers form inductors. This multi-layer approach significantly reduces the footprint area while preserving component functionality and tolerance control.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If conductor tracks are applied directly on multi-layer substrate, then space requirement is reduced, but manufacturing tolerances are not compensated

Engineering Contradiction:
Improvespace requirementVSAvoidtolerance compensation
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent incorporates compensation mechanisms directly into the conductor track design. The tracks are configured with geometric features that pre-compensate for expected manufacturing variations in layer alignment and dimensions. This beforehand cushioning ensures that even with typical manufacturing tolerances, the final electrical characteristics (inductance values) remain within specified ranges.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Area of stationary object

If integrated capacitances are used, then space requirement is reduced, but capacitance value is limited and symmetry condition is not optimally fulfilled

Engineering Contradiction:
Improvespace requirementVSAvoidcapacitance accuracy
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent employs asymmetric conductor surface configurations to achieve symmetric electrical characteristics. By carefully designing the geometry and positioning of conductive surfaces on different layers, the physical asymmetry compensates for manufacturing tolerances, ensuring that the capacitance values meet symmetry requirements. The asymmetric design allows for tolerance compensation while maintaining the desired electrical symmetry.

Inventive Principle:
Principle #4Asymmetry

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 approach results in a compact, symmetric filter with stable high-frequency properties and reduced manufacturing tolerances, effectively addressing space and symmetry issues while maintaining consistent capacitance and improved high-frequency performance.

Implementation Method 1

The conductive surfaces form a capacitance. The conductive surfaces partially overlap and form an overlap area.

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a first inductance, which is spatially concentrated... The lumped inductance is implemented as a conductor track on the substrate.

Methodology Applied
Scientific EffectInductance: Inductor

Data Source

PatentEP2215900B1Filter in a multi-layer substrate with an electrical circuit arrangement having compact elements
Publication Date: 2011.06.22 ROHDE & SCHWARZ GMBH & CO KG
  • EP2215900B1 patent drawingFigure 1
  • EP2215900B1 patent drawingFigure 2
  • EP2215900B1 patent drawingFigure 3

AI summary

The invention relates to an electrical circuit arrangement, having a substrate (16) and at least two conductive surfaces (10, 11, 12, 13). The substrate (16) comprises at least one layer. At least one layer of the substrate (16) is located between the at least two conductive surfaces (10, 11, 12, 13). The at least two conductive surfaces (10, 11, 12, 13) form a capacity. The conductive surfaces (10, 11, 12, 13) partially overlap and form an overlap surface. The resulting overlap surface remains extensively constant when the conductive surfaces (10, 11, 12, 13) are displaced up to a limit value of displacement.