Stacked Filter Assembly for Compact RF Signal Processing

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Solution Overview

Problem

The existing technologies for RF filters face challenges in achieving a cost-effective and compact design, particularly in the fabrication of distributed element filters, which require tight tolerances and are costly to produce, while also needing to be packaged in a space-efficient manner.

Innovation Solution

A filter circuit is designed with multiple conductive and dielectric layers on a printed wiring board, where distributed element filters are formed by conductors sandwiched between dielectric and ground layers, connected via vias and solder joints, allowing for a compact and modular structure that reduces fabrication costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If distributed element filters are fabricated using conventional methods, then filter performance is achieved, but fabrication cost increases due to tight tolerances

Engineering Contradiction:
Improvetight tolerancesVSAvoidfabrication cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent transitions from planar 2D filter layouts to a 3D stacked configuration with multiple conductive layers separated by dielectric layers. This vertical stacking allows filters to be arranged in three dimensions, reducing the footprint area while maintaining filter performance and relaxing fabrication tolerance requirements through the additional dimensional freedom.

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

Solution Approach 2:

The patent implements a nested structure where multiple conductive layers are embedded within dielectric layers, forming a layered sandwich structure. Each conductive layer containing filter elements is nested between dielectric layers, allowing compact integration of multiple filters in a vertical stack, thereby reducing overall device area and fabrication complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Area of stationary object

If distributed element filters are packaged conventionally, then individual filters are accommodated, but space efficiency is reduced

Engineering Contradiction:
Improvepackaging areaVSAvoidspace efficiency
Core Design Contradiction:
Area of stationary objectVSProductivity

Solution Approach 1:

The patent employs vertical stacking of multiple conductive layers containing filters, transitioning from horizontal 2D packaging to 3D vertical packaging. This approach consolidates multiple filters into a compact vertical column, dramatically reducing the horizontal footprint area while increasing space efficiency through utilization of the vertical dimension.

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

Solution Approach 2:

The patent merges multiple individual filter packages into a single integrated stacked structure. Multiple conductive layers with filters are combined vertically within a unified package, sharing common support structures and interconnection pathways, thereby reducing total packaging area and improving space efficiency compared to separate individual packages.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3400626B1Stacked filters
Publication Date: 2021.03.17 RAYTHEON CO
  • EP3400626B1 patent drawingFigure 1A~1B
  • EP3400626B1 patent drawingFigure 1C
  • EP3400626B1 patent drawingFigure 2

AI summary

A filter assembly in a multi-layer printed wiring board. One or more conductors is formed on an internal layer of a printed wiring board. Surrounding dielectric layers and ground layers form, together with the conductors of the internal layer, microstrip or stripline transmission lines and distributed element filters. The filter assembly may include a plurality of internal conductive layers, each sandwiched between dielectric layers and ground layers, and each internal layer may include a plurality of distributed element filters. Connections from each filter to the surface of the filter assembly are formed by vias, and connections from the surface of the filter assembly to a host board are formed by solder joints.