Duplexer Impedance Tuning Using ML Leakage Feedback

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Solution Overview

Problem

Determining the impedance of an antenna in radio frequency devices is challenging, leading to inefficient isolation between transmitter and receiver signals, as existing impedance tuners often overshoot or mismatch, resulting in poor isolation performance.

Innovation Solution

The implementation of a radio frequency device with a voltage standing wave ratio (VSWR) detector and machine-learning models to accurately determine antenna impedance, adjusting impedance tuner settings based on measured leakage values and reflection coefficients, and using multiple smaller machine-learning models for efficient impedance matching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional impedance tuning methods are used, then the impedance tuner can be adjusted, but it often overshoots or mismatches the antenna impedance, resulting in poor isolation performance

Engineering Contradiction:
Improveantenna impedance determination accuracyVSAvoidisolation performance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the system measures transmitter leakage and receiver leakage, uses these measurements to estimate antenna impedance through a machine learning model, and adjusts the impedance tuner accordingly. This closed-loop feedback system continuously optimizes the impedance matching, preventing overshoot and mismatch issues inherent in traditional open-loop tuning methods.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces traditional mechanical or manual impedance tuning mechanisms with a machine learning-based estimation system. Instead of relying on conventional tuning procedures that may overshoot, the system uses trained machine learning models to predict optimal impedance settings based on leakage measurements, achieving more precise and reliable impedance matching.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If multiple test impedance settings are applied to determine antenna impedance, then measurement accuracy improves, but the tuning process becomes more complex and time-consuming

Engineering Contradiction:
Improveantenna impedance measurement accuracyVSAvoidtuning time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs pre-trained machine learning models that have already learned the relationship between leakage patterns and antenna impedance characteristics during the training phase. During actual operation, the system only needs to perform a single or minimal number of leakage measurements and apply the pre-trained model, eliminating the need for multiple iterative test settings and significantly reducing tuning time while maintaining high measurement accuracy.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If a single large machine-learning model is used for impedance matching, then accuracy is maintained, but computational complexity and processing requirements increase

Engineering Contradiction:
Improveimpedance estimation accuracyVSAvoidmachine-learning model complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the impedance matching task into multiple independent stages, each handled by a specialized machine learning model. One model estimates antenna impedance from leakage measurements, while another determines optimal impedance tuner settings based on the estimated impedance. This segmentation reduces the complexity of individual models, making them more computationally efficient and easier to implement while maintaining overall system accuracy.

Inventive Principle:
Principle #1Segmentation

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 approach enables efficient and accurate determination of antenna impedance, improving isolation between transmitter and receiver signals by precisely matching impedance tuner settings, reducing unnecessary tuning adjustments and enhancing communication quality.

Implementation Method 1

a voltage standing wave ratio detector coupled to the duplexer and the antenna. The voltage standing wave ratio detector determines an antenna impedance at the antenna.

Methodology Applied
Scientific EffectVoltage standing wave ratio: Reflection

Data Source

PatentUS12040772B2Machine-learning based tuning algorithm for duplexer systems
Publication Date: 2024.07.16 APPLE INC
  • US12040772B2 patent drawing
  • US12040772B2 patent drawing
  • US12040772B2 patent drawing

AI summary

This disclosure provides techniques for impedance matching. A radio frequency (RF) device includes a power detector to determine a transmitter leakage and a post-processing unit to determine a receiver leakage, and determines if isolation is acceptable based on the leakages. The RF device may include a device for measuring antenna impedance. Otherwise, the RF device may select multiple tuner settings (e.g., capacitor values) for test signals to be transmitted and received at a target frequency, determine multiple sets of leakage values, determine multiple reflection coefficients based on the multiple sets of leakage values, and determine an estimated antenna impedance at the target frequency based on the reflection coefficients. The RF device then determines impedance tuner settings based on the measured or estimated antenna impedance. Alternatively, the RF device determines impedance tuner settings using an inverse machine-learning model based on a determined matching impedance.