RF Front-End Circuit with Segmented Switching for 5G Isolation

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Solution Overview

Problem

The existing radio frequency front-end circuits in 5G mobile terminals suffer from high insertion loss, poor isolation, and complex design, which are exacerbated by the use of three-pole three-throw switches, leading to increased costs and reduced reception performance due to long wiring and layout restrictions.

Innovation Solution

The implementation of a double-pole four-throw switch and two single-pole double-throw switches replaces the three-pole three-throw switch, allowing for a more compact layout, reduced line insertion loss, and improved signal isolation, with components deployed near the antenna side to minimize RF cables and sockets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a three-pole three-throw switch is used in high frequency and large bandwidth applications, then the circuit can achieve signal switching functionality, but the insertion loss increases due to larger line loss

Engineering Contradiction:
Improvesignal switching functionalityVSAvoidinsertion loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent divides the signal switching function into multiple independent single-pole double-throw switches instead of using a single three-pole three-throw switch. Each switch handles a specific signal path independently, reducing the line loss for each individual path while maintaining overall switching functionality. This segmentation allows for shorter and more direct signal routes for each switch component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple single-pole double-throw switches to collectively perform the function of a three-pole three-throw switch. By merging these simpler switch components, the system achieves the required signal routing capability while reducing insertion loss through optimized signal paths and shorter wiring for each individual switch.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If a three-pole three-throw switch with many switching paths is used, then signal routing flexibility is achieved, but isolation between paths becomes insufficient leading to transmitted signal interference with received signal

Engineering Contradiction:
Improvesignal routing flexibilityVSAvoidsignal interference
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the signal switching into multiple independent single-pole double-throw switches, each handling a specific signal path. This segmentation improves isolation between paths because each switch operates independently with its own dedicated connections, preventing transmitted signals from interfering with received signals while maintaining routing flexibility through coordinated switching of multiple independent components.

Inventive Principle:
Principle #1Segmentation

3Reliability

If improvements are made to address the shortcomings of three-pole three-throw switches, then performance is improved, but the cost increases making it much higher than a DPDT switch

Engineering Contradiction:
Improveswitching performanceVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the expensive three-pole three-throw switch with multiple single-pole double-throw switches that are more cost-effective. By using simpler, cheaper switch components in multiple units, the overall system achieves comparable or superior performance while significantly reducing the cost per switch component, making the solution more economically viable for 5G NR systems.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Reliability

If existing components are used with long wiring between modules, then circuit functionality is achieved, but frequency loss increases due to longer path length

Engineering Contradiction:
Improvecircuit functionalityVSAvoidfrequency loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent integrates the single-pole double-throw switches directly into the antenna module assembly, merging previously separate components into a unified structure. This integration eliminates the need for long external wiring between modules, significantly reducing the signal path length and associated frequency loss while maintaining full circuit functionality for 5G NR operations.

Inventive Principle:
Principle #5Merging (Combining)

5Device complexity

If layout restrictions of two three-pole three-throw switches are considered, then circuit design is constrained, but reception performance loss increases by 2 to 3 dB

Engineering Contradiction:
Improvecircuit design constraintsVSAvoidreception performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments the switching function into multiple single-pole double-throw switches that can be independently arranged and integrated into the antenna module. This segmentation provides greater layout flexibility compared to two large three-pole three-throw switches, allowing for optimized signal paths and shorter connections that reduce reception performance loss by minimizing the distance signals must travel through lossy interconnections.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4016855B1Radio frequency front-end circuit and mobile terminal
Publication Date: 2025.08.27 VIVO MOBILE COMM CO LTD
  • EP4016855B1 patent drawingFigure 1
  • EP4016855B1 patent drawingFigure 2
  • EP4016855B1 patent drawingFigure 3

AI summary

Embodiments of this disclosure provide a radio frequency front-end circuit and a mobile terminal. The radio frequency front-end circuit includes: a first transmit path, a first receive path, a second receive path, a third receive path, a fourth receive path, a double-pole four-throw switch, a first single-pole double-throw switch, a second single-pole double-throw switch, a third single-pole double-throw switch, a first antenna, a second antenna, a third antenna, and a fourth antenna.