RF Switch Circuit With Shunt Grounding for Carrier Aggregation Isolation

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Solution Overview

Problem

Existing radio-frequency switch circuits do not support carrier aggregation (CA) and fail to maintain sufficient isolation between antenna and radio-frequency circuits, especially when multiple frequency bands are used simultaneously.

Innovation Solution

A radio-frequency switch configuration with two switch circuits and shunt switches that selectively connect common terminals to ground, allowing for CA while increasing isolation by switching between conductive and non-conductive states, and incorporating matching networks for improved matching and reduced insertion loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single switch circuit is used to connect antenna to radio-frequency circuits, then the device complexity is reduced, but the ability to support carrier aggregation and maintain isolation is degraded

Engineering Contradiction:

Improvecarrier aggregation supportVSAvoidswitch circuit structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the single switch circuit into multiple independent switch circuits (first switch circuit and second switch circuit), each handling specific frequency bands. This segmentation enables carrier aggregation support while maintaining manageable complexity through modular design, where each switch circuit can be independently controlled and optimized.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent adds a new dimension to the switch circuit architecture by introducing multiple switch circuits operating in parallel for different frequency bands, rather than using a single switch circuit. This dimensional expansion enables simultaneous handling of multiple bands for carrier aggregation while maintaining isolation through independent control of each switch circuit.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the common terminal is connected to ground to increase isolation, then isolation between antenna and radio-frequency circuits is improved, but the ability to perform carrier aggregation is degraded

Engineering Contradiction:

Improveisolation between antenna and radio-frequency circuitVSAvoidcarrier aggregation support

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic control of the shunt switch connection to ground, allowing the system to adapt between isolation mode and carrier aggregation mode. The shunt switch can be dynamically connected or disconnected based on operational requirements, enabling the system to maintain high isolation when needed while supporting carrier aggregation when required.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the electrical parameter (connection state) of the shunt switch between connected and disconnected states. By controlling the shunt switch parameter dynamically, the system can adjust the isolation level and carrier aggregation capability according to operational needs, resolving the contradiction between maintaining isolation and supporting carrier aggregation.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If multiple switch circuits are added to support carrier aggregation, then carrier aggregation capability is improved, but the device complexity increases

Engineering Contradiction:

Improvecarrier aggregation supportVSAvoidnumber of switch circuits

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs each switch circuit to be multi-functional, handling both isolation and carrier aggregation functions within the same circuit structure. The first and second switch circuits can independently perform switching operations for different frequency bands, providing universal functionality that reduces the need for additional specialized components, thereby limiting complexity growth despite enhanced carrier aggregation capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If shunt switches are used to control ground connection, then isolation is improved, but the device complexity increases

Engineering Contradiction:

Improveisolation between common terminal and groundVSAvoidswitch circuit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the shunt switch functionality with the existing switch circuit structure, integrating ground connection control directly into the switch circuit design. This merging approach allows isolation control to be achieved without adding completely separate isolation circuits, thereby improving isolation while limiting the increase in overall device complexity through integrated design.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10985794B2Radio-frequency switch and communication device

Publication Date: 2021.04.20 MURATA MFG CO LTD

AI summary

A radio-frequency switch includes a first switch circuit including a first common terminal, at least two first selection terminals, a first switch that selectively connects the first common terminal and the at least two first selection terminals to each other, and a first shunt switch that switches the first common terminal and ground between a conductive state and a non-conductive state with each other, and a second switch circuit including a second common terminal that is connected to the first common terminal, at least two second selection terminals, and a second switch that selectively connects the second common terminal and the at least two selection terminals to each other.