Triple Inductor Transformer Layout for Multiband Port Isolation

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Solution Overview

Problem

Current diplexers and duplexers in wireless communications systems require separate components for each radio frequency band and transmission technology, leading to increased size and cost, and suffer from electromagnetic coupling issues that affect performance.

Innovation Solution

A triple inductor transformer is integrated into diplexers or duplexers, featuring a first inductor with a shared port and second and third inductors oriented at different angles to reduce magnetic coupling, allowing for independent signal transmission and reception across multiple bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate components are used for each radio frequency band and transmission technology, then reliability and performance are improved, but device size and cost increase

Engineering Contradiction:
ImproveperformanceVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent combines multiple separate diplexer/duplexer components into a single integrated triple inductor transformer that handles multiple radio frequency bands and transmission technologies simultaneously. The three inductors are magnetically coupled to provide separate signal paths for different frequency bands, eliminating the need for multiple discrete components while maintaining performance.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The triple inductor transformer is designed to perform multiple functions within a single device, supporting both diplexer and duplexer operations across multiple frequency bands. The structure enables simultaneous handling of different transmission technologies (e.g., LTE, WiFi, Bluetooth) through its three magnetically coupled inductors, each configured for specific frequency ranges.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If separate components are used for each radio frequency band and transmission technology, then reliability and performance are improved, but device cost increases

Engineering Contradiction:
ImproveperformanceVSAvoiddevice cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple separate diplexer/duplexer components into a single integrated triple inductor transformer that handles multiple radio frequency bands and transmission technologies simultaneously. The three inductors are magnetically coupled to provide separate signal paths for different frequency bands, eliminating the need for multiple discrete components while maintaining performance.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If traditional diplexer/duplexer structures are used, then signal transmission is achieved, but electromagnetic coupling between components causes performance degradation

Engineering Contradiction:
Improvesignal transmissionVSAvoidelectromagnetic coupling
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent utilizes magnetic coupling between the three inductors as a beneficial mechanism to achieve signal separation and filtering. By designing the inductors with specific magnetic coupling coefficients, the structure converts what is typically a harmful effect (electromagnetic coupling) into a useful function for frequency-selective signal routing, where the coupled inductors naturally filter different frequency bands without requiring additional shielding or isolation components.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

The triple inductor transformer reduces electromagnetic coupling, minimizes insertion loss, and achieves high isolation between ports, enabling efficient multiband operation while reducing the size and cost of wireless communication devices.

Implementation Method 1

The second inductor includes a first portion configured to permit current flow in a clockwise direction and a second portion configured to permit current flow in a counter-clockwise direction. The counter-clockwise direction is opposite the clockwise direction to reduce magnetic coupling between the second inductor and the third inductor based on magnetic coupling cancellation.

Methodology Applied
Scientific EffectMagnetic coupling cancellation: Electromagnetic Induction

Data Source

PatentEP3803919B1Triple inductor transformer for multiband radio frequency integrated circuits
Publication Date: 2025.01.08 QUALCOMM INC
  • EP3803919B1 patent drawingFigure 1
  • EP3803919B1 patent drawingFigure 2
  • EP3803919B1 patent drawingFigure 3

AI summary

A transformer has a first inductor that includes a first port. The transformer also has a second inductor magnetically coupled to the first inductor. The second inductor includes a second port. The second inductor includes a first portion configured to permit current flow in a clockwise direction and a second portion configured to permit current flow in a counter-clockwise direction. The transformer also has a third inductor magnetically coupled to the first inductor. The third inductor includes a third port. The counter-clockwise direction is opposite the clockwise direction to reduce magnetic coupling between the second inductor and the third inductor based on magnetic coupling cancellation.