Carrier Aggregation Phase Control for Band Isolation and Low Noise

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Solution Overview

Problem

Existing radio-frequency (RF) carrier aggregation systems face challenges in maintaining low noise figure and sufficient band isolation, especially when aggregating frequency bands that are close to each other, often requiring additional high-Q filters that increase cost and complexity.

Innovation Solution

A carrier aggregation (CA) circuit with a diplexer configuration that includes phase shifting circuits and switches, allowing for impedance matching and open-circuit conditions for non-target frequency bands, thereby improving noise figure performance without the need for additional high-Q filters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional high-Q filters are used to improve band isolation and noise figure, then isolation between frequency bands is improved, but device complexity and cost increase

Engineering Contradiction:

Improvenoise figureVSAvoidfilter configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The signal path is divided into separate first and second paths, each handling a specific frequency band. The first path processes the first frequency band while the second path processes the second frequency band, allowing independent optimization of each path without requiring additional high-Q filters for isolation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each path is configured with specific impedance characteristics tailored to its frequency band. The first path provides matched impedance for the first band and open-circuit impedance for the second band, while the second path provides matched impedance for the second band and open-circuit impedance for the first band, achieving band-specific optimization.

Inventive Principle:

Principle #3Local quality

2Reliability

If additional high-Q filters are used to improve band isolation, then isolation between frequency bands is improved, but device complexity increases

Engineering Contradiction:

Improveband isolationVSAvoidfilter configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #3Local quality

3Device complexity

If a common path is used for multiple frequency bands, then device complexity is reduced, but noise figure and band isolation deteriorate

Engineering Contradiction:

Improvecircuit configurationVSAvoidnoise figure

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first and second paths are combined at a common output node, allowing the system to achieve the performance benefits of separate paths while maintaining a compact structure. The combined configuration enables carrier aggregation functionality without the full complexity of completely separate processing chains.

Inventive Principle:

Principle #5Merging (Combining)

4Device complexity

If a common path is used for multiple frequency bands, then device complexity is reduced, but band isolation deteriorates

Engineering Contradiction:

Improvecircuit configurationVSAvoidband isolation

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10784903B2Phase control for carrier aggregation

Publication Date: 2020.09.22 SKYWORKS SOLUTIONS INC

AI summary

Phase control for carrier aggregation. In some embodiments, a carrier aggregation circuit can include a first filter configured to allow operation in a first frequency band, and a second filter configured to allow operation in a second frequency band. The circuit can further include a first path implemented between the first filter and a common node, with the first path being configured to provide a substantially matched impedance for the first frequency band and a substantially open-circuit impedance for the second frequency band. The circuit can further include a second path implemented between the second filter and the common node, with the second path being configured to provide a substantially matched impedance for the second frequency band and a substantially open-circuit impedance for the first frequency band.