Front End Module Diplexer with Notch Filter Extractor Path

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Solution Overview

Problem

Existing frontend modules for carrier aggregation in mobile phone systems face challenges in efficiently separating signals across multiple frequency bands with minimal losses, especially when using a single antenna or metallic housings, which complicate signal separation and increase costs.

Innovation Solution

The proposed frontend module incorporates a diplexer with a high diplex distance and a notch filter to separate frequency ranges, along with an extractor path and band pass filter to extract signals within a specific blocking area, allowing for simpler and more efficient signal separation across multiple frequency bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single-antenna solution with a cellular hexaplexer is used for carrier aggregation, then band separation is achieved, but the device complexity and cost increase significantly

Engineering Contradiction:
Improveband separation capabilityVSAvoidmultiplexer design complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the frequency band separation task into multiple stages: a first diplexer separates the first frequency band from the second frequency band, and a second diplexer separates the second frequency band into third and fourth bands. This segmentation approach replaces the need for a complex hexaplexer with simpler, cascaded diplexers, reducing device complexity while maintaining band separation capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an extractor path as an additional dimension to the signal path, branching off from the main path between the first and second diplexers. This extractor path handles the second frequency band separately, allowing the main path to focus on separating the first and fourth bands. This dimensional addition simplifies the overall multiplexer design by distributing the separation task across multiple paths.

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

2Adaptability or versatility

If a triplexer with narrow diplexer spacing is used to separate LB, MB, and HB bands, then band separation is achieved, but insertion loss increases and implementation becomes difficult

Engineering Contradiction:
Improvemulti-band separationVSAvoidinsertion loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent segments the band separation into distinct stages using cascaded diplexers with optimized spacing. The first diplexer separates the first frequency band (e.g., LB) from the second frequency band (e.g., MB+HB), and the second diplexer further separates the second frequency band into third and fourth bands. This segmentation allows each diplexer to be designed with appropriate diplexer spacing, avoiding the narrow spacing required in a single-stage triplexer, thereby reducing insertion loss.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the second frequency band partially through the extractor path before it reaches the second diplexer. This partial extraction reduces the burden on the second diplexer, allowing it to operate with optimized spacing and reduced insertion loss. The extractor path handles part of the separation task, enabling the main path to focus on the remaining bands with more favorable spacing conditions.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If multiple receive channels are connected in parallel for carrier aggregation, then data transmission rate increases, but signal paths block each other and signals leak into other bands

Engineering Contradiction:
Improvedata transmission rateVSAvoidpower loss due to signal blocking and leakage
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent segments the signal paths for different frequency bands using cascaded diplexers and an extractor path. Each diplexer and the extractor path provide physical separation for different frequency ranges, ensuring that signals in parallel receive channels do not block or leak into each other. This segmentation maintains signal integrity while enabling parallel operation of multiple receive channels for carrier aggregation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The extractor path acts as an intermediary that branches off from the main signal path between the first and second diplexers. It provides an intermediate separation stage for the second frequency band, preventing potential signal blocking or leakage between the first and fourth frequency bands. This intermediary path ensures clean signal separation while maintaining the parallel structure needed for high data transmission rates.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution enables efficient separation of multiple frequency ranges with reduced insertion losses, facilitating the use of simpler technologies like LTCC or laminates for diplexer implementation, and allowing for independent operation of frequency ranges without mutual interference.

Implementation Method 1

a diplexer (or higher multiplexer) in a first signal path coupled to an antenna connection. The diplexer separates a first and a second frequency range from each other and assigns them to a first and a second sub-path on the output side, respectively

Methodology Applied
Scientific EffectFrequency separation: Filter (electronic)

Implementation Method 2

a notch filter is provided, which is coupled to the diplexer and has a first stopband. The notch filter is coupled between the antenna connection and the diplexer. The notch filter is designed such that its stopband is located between the first and second frequency ranges, but does not overlap with either of the two adjacent frequency ranges

Methodology Applied
Scientific EffectStopband filtering: Filter (electronic)

Implementation Method 3

A first extractor path is coupled to a node located in the signal path between the antenna connector and the first notch filter. Signals within the stopband can thus be extracted from the signal line via the first extractor path

Methodology Applied
Scientific EffectSignal extraction: Filter (electronic)

Implementation Method 4

A bandpass filter is also arranged in the extractor path, which is permeable to the extractor band but attenuates other frequencies

Methodology Applied
Scientific EffectBandpass filtering: Filter (electronic)

Data Source

PatentEP3411954B1Front end module for carrier aggregation operation
Publication Date: 2025.04.23 SNAPTRACK INC
  • EP3411954B1 patent drawingFigure 1A~1B
  • EP3411954B1 patent drawingFigure 2A~2B
  • EP3411954B1 patent drawingFigure 3~4

AI summary

For improved band separation in a front end module, an extractor band is extracted by means of an extractor arrangement comprising a notch filter and an extractor path togther with a bandpass filter. The front end module also comprises a diplexer which separates a first and a second frequency range by a diplexer distance. The extractor band is located between the two frequency ranges such that it does not overlap with either of the two frequency ranges. As a result, the distance between the two frequency ranges increases beyond the diplexer distance itself.