Overlapping Multiplexer Filter Layout for Better Isolation

Solution Overview

Problem

Existing multiplexers face challenges in achieving optimal isolation characteristics while minimizing size, as overlapping filters lead to interference and non-overlapping configurations result in increased size.

Innovation Solution

The multiplexer design includes a first and second substrate with filters having series and parallel resonators connected through wiring lines, where parts of the filters overlap in plan view to optimize electrostatic capacitance ratios, improving isolation characteristics without increasing size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If filters are arranged to overlap in plan view, then the size of the multiplexer is reduced, but isolation characteristics deteriorate due to interference between filters

Engineering Contradiction:

Improvesize of multiplexerVSAvoidisolation characteristics

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the treatment of resonators based on their spatial relationship with the other filter. First resonators are positioned to overlap with the other filter in plan view and are designed with specific electrostatic capacitance ratios, while second resonators are positioned to not overlap with the other filter. This localized differentiation allows the multiplexer to achieve both compact size and good isolation characteristics.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the electrostatic capacitance parameters of the resonators to resolve the contradiction. Specifically, for first resonators that overlap with the other filter, the ratio of electrostatic capacitance between the series resonator and parallel resonator is set to be less than 1, while for second resonators that do not overlap, the ratio is set to be greater than 1. This parameter differentiation enables the system to achieve both size reduction and maintained isolation characteristics.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If filters are arranged not to overlap in plan view, then isolation characteristics are improved, but the size of the multiplexer increases

Engineering Contradiction:

Improveisolation characteristicsVSAvoidsize of multiplexer

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent applies local quality by differentiating the treatment of resonators based on their spatial relationship with the other filter. First resonators are positioned to overlap with the other filter in plan view and are designed with specific electrostatic capacitance ratios, while second resonators are positioned to not overlap with the other filter. This localized differentiation allows the multiplexer to achieve both compact size and good isolation characteristics.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the electrostatic capacitance parameters of the resonators to resolve the contradiction. Specifically, for first resonators that overlap with the other filter, the ratio of electrostatic capacitance between the series resonator and parallel resonator is set to be less than 1, while for second resonators that do not overlap, the ratio is set to be greater than 1. This parameter differentiation enables the system to achieve both size reduction and maintained isolation characteristics.

Inventive Principle:

Principle #35Parameter changes

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 effectively suppresses signals in specific bands, enhancing isolation characteristics while reducing the overall size of the multiplexer by strategically overlapping filter components.

Implementation Method 1

electrostatic capacitance values of a series resonator and a parallel resonator in one or more first basic sections including the one or more first resonators are respectively represented by Cs1 and Cp1

Methodology Applied

Scientific EffectElectrostatic capacitance: Capacitance

Data Source

PatentUS10826460B2Multiplexer

Publication Date: 2020.11.03 TAIYO YUDEN KK

AI summary

A multiplexer includes: a filter located on a surface of a substrate and including first series and parallel resonators and a first wiring line; and another filter located on another surface of another substrate and including second series and parallel resonators and a second wiring line, each of first resonators among the second series and parallel resonators overlapping with the first series and parallel resonators, and/or the first wiring line, each of second resonators other than the first resonators among the second series and parallel resonators overlapping with none of the first series and parallel resonators and the first wiring line, when capacitances of series and parallel resonators in first basic sections including the first resonators are represented by Cs1 and Cp1, and capacitances of series and parallel resonators in second basic sections not including the first resonators are represented by Cs2 and Cp1, Cp1/Cs1 being less than Cp2/Cs2.