High Frequency Filter Multilayer Structure

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Solution Overview

Problem

Conventional high frequency filters with multilayer balanced structures face challenges in reducing profile height while maintaining a low mounting area, as they require a larger number of insulator layers for electromagnetic coupling, leading to increased size and complexity.

Innovation Solution

A high frequency filter design featuring a multilayer structure with a higher dielectric constant insulator layer for transmission lines, allowing for edge coupling and reduced insulator layer count, along with an impedance adjuster portion on the same insulator layer, which reduces the overall profile height and mounting area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If coils are arranged on different insulator layers to achieve electromagnetic coupling, then the mounting area is reduced, but the profile height increases due to additional insulator layers

Engineering Contradiction:

Improvemounting areaVSAvoidprofile height

Core Design Contradiction:

Area of stationary objectVSLength of stationary object

Solution Approach 1:

The patent transitions from vertical stacking (different layers) to horizontal arrangement (same layer) for electromagnetic coupling. By placing first and second coils on the same insulator layer and coupling them through edge coupling in the planar direction, the design eliminates the need for additional insulator layers while maintaining electromagnetic coupling functionality, thus reducing profile height while keeping mounting area compact.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent divides the electromagnetic coupling function into two independent coupling paths: first coil to third coil, and second coil to fourth coil. This segmentation allows each coil pair to be optimally arranged on the same layer with edge coupling, avoiding the need for vertical stacking while achieving the required coupling effectiveness.

Inventive Principle:

Principle #1Segmentation

2Reliability

If more insulator layers are stacked to accommodate multiple coils, then electromagnetic coupling is achieved, but the device complexity and profile height increase

Engineering Contradiction:

Improveelectromagnetic couplingVSAvoidnumber of insulator layers

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The insulator layer serves multiple functions simultaneously: it provides mechanical support for all four coils, enables edge coupling between adjacent coils through its dielectric properties, and provides a common reference plane. This multi-functionality eliminates the need for separate insulator layers for each coupling pair, reducing overall device complexity while maintaining reliable electromagnetic coupling.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the functions of multiple insulator layers into a single insulator layer. Instead of using separate insulator layers for each coil pair, all four coils are arranged on the same insulator layer, which handles both coupling relationships simultaneously, thereby reducing the number of insulator layers and simplifying the overall structure.

Inventive Principle:

Principle #5Merging (Combining)

3Length of stationary object

If coils are arranged on the same insulator layer for edge coupling, then profile height is reduced, but the mounting area may increase

Engineering Contradiction:

Improveprofile heightVSAvoidmounting area

Core Design Contradiction:

Length of stationary objectVSArea of stationary object

Solution Approach 1:

The patent arranges the four coils in a compact nested configuration where the first and second coils are positioned adjacent to each other, and the third and fourth coils are positioned adjacent to each other, with appropriate spacing for edge coupling. This nested arrangement on the same insulator layer minimizes the overall footprint while maintaining the required coupling distances, thus reducing mounting area despite the planar arrangement.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 design achieves a lower profile height and prevents an increase in mounting area by utilizing a higher dielectric constant for specific insulator layers, enabling efficient electromagnetic coupling and impedance adjustment, thereby simplifying the filter structure and reducing stray capacitance.

Implementation Method 1

a second transmission line configured to produce electromagnetic coupling with the first transmission line on a same insulator layer and transmit an output signal

Methodology Applied

Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Implementation Method 2

a conductor layer configured to define capacitors with the first transmission line and the second transmission line with the insulator layer in between

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS9673498B2High frequency filter

Publication Date: 2017.06.06 MURATA MFG CO LTD

AI summary

In a high frequency filter, a multilayer structure includes a plurality of insulator layers, a first transmission line transmits an input signal, and a second transmission line is electromagnetic coupled with the first transmission line on the same insulator layer and transmits an output signal. A conductor layer defines capacitors with the first transmission line and the second transmission line with the insulator layer in between. A dielectric constant of the insulator layer that comes in contact with the first transmission line and the second transmission line is higher than a dielectric constant of an insulator layer other than the insulator layer.