Closed-Loop Antenna Impedance Tuning Without Lookup Tables
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Solution Overview
Problem
Impedance mismatch in radio antenna transmission systems leads to power reflection and reduced transmission efficiency, particularly in mobile devices with limited power supply, where conventional impedance tuning methods are inefficient due to hardware uncertainties and reliance on ideal tuner responses.
Innovation Solution
A data-driven method for configuring antenna impedance tuners using a tuner code search algorithm, which determines an optimal tuner code based on cost functions learned from data, incorporating both analytic and black box models, such as neural networks, to maximize instantaneous and asymptotic performance by adjusting tuner components like switches and inductors/capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lookup table-based impedance tuning methods are used, then the system is simple to implement, but it cannot effectively compensate for hardware uncertainties and environmental changes
Solution Approach 1:
The patent implements a feedback-based impedance tuning algorithm that continuously monitors the antenna impedance and adjusts tuner components accordingly. The algorithm uses measured impedance data to iteratively optimize the matching network configuration, enabling the system to adapt to hardware uncertainties and environmental changes rather than relying on pre-stored lookup tables
Solution Approach 2:
The impedance tuning system performs self-calibration by automatically measuring its own impedance characteristics and adjusting its configuration without external intervention. The algorithm uses the device's own operational data to learn and optimize tuning parameters, enabling the system to adapt to its specific hardware variations and operating conditions
2Reliability
If ideal response-based cost functions are used, then the computational model is simple, but it does not account for hardware uncertainties
Solution Approach 1:
The patent transforms the cost function from using idealized electrical parameters to using empirically measured operational parameters. The algorithm replaces theoretical impedance values with actual measured data from the hardware, allowing the cost function to reflect real-world behavior including hardware uncertainties and environmental variations
3Measurement precision
If exhaustive tuner code search is performed, then the optimal tuning solution is found, but the computational complexity and time consumption increase significantly
Solution Approach 1:
The patent performs preliminary exploration of the tuner code space by evaluating a subset of candidate configurations before final optimization. The algorithm uses initial measurements and preliminary tuning results to guide subsequent search directions, reducing the need for exhaustive search while maintaining optimization accuracy
Solution Approach 2:
The tuning algorithm dynamically adapts its search strategy based on real-time measurements and progress. Rather than using a static exhaustive search, the algorithm adjusts its exploration behavior according to the observed impedance landscape, intensifying search in promising regions and reducing search in already-explored areas
Data Source
AI summary
According to an embodiment, a method in a closed-loop antenna impedance tuning (CL-AIT) system is provided. The method includes determining whether a transmitted power is above a pre-determined threshold, when the transmitted power is above the pre-determined threshold, determining a bypass input reflection coefficient, determining whether the bypass input reflection coefficient is greater than a bypass threshold, and when the bypass input reflection coefficient is greater than the bypass threshold, determining an optimal tuner code based on a tuner code search algorithm.