RF Circuit Impedance Calibration Using Antenna Tuner Feedback
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Solution Overview
Problem
The calibration of radio frequency circuits for multiple transmission bands during manufacturing is time and cost intensive, and existing methods require multiple impedance measurements for different antenna tuner settings, which can be cumbersome and expensive.
Innovation Solution
A control circuit and apparatus that determine calibration values for radio frequency circuits based on at least two impedance measurements and antenna tuner configurations, using a feedback receiver to measure impedance between the transmit unit and antenna, and applying correction values to ensure accurate impedance matching without factory calibration, allowing for online calibration during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If factory calibration is performed for multiple transmission bands, then manufacturing precision is improved, but loss of time and manufacturing cost increase
Solution Approach 1:
The system performs self-calibration by automatically determining calibration values through impedance measurements and signal processing, eliminating the need for manual factory calibration across multiple transmission bands. The control circuit autonomously adjusts calibration parameters based on measured impedance data, enabling the device to calibrate itself during operation rather than requiring time-consuming factory calibration procedures.
Solution Approach 2:
The patent changes the calibration approach by determining calibration values dynamically through impedance measurements and signal processing algorithms rather than using fixed factory-calibrated values. The system measures impedance at different frequencies and transmission bands, then calculates appropriate calibration parameters based on these measurements, allowing adaptation to actual operating conditions without manual intervention.
2Measurement precision
If multiple impedance measurements are taken for different antenna tuner settings, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The control circuit performs multiple functions using a single integrated system: it measures impedance, processes signals, determines calibration values, and adjusts transmission parameters. The same control circuit handles impedance measurements across multiple transmission bands and frequencies, eliminating the need for separate dedicated circuits for each function and reducing overall system complexity while maintaining measurement precision.
Solution Approach 2:
The system uses feedback from impedance measurements to automatically determine calibration values. The control circuit measures impedance, compares it against expected values, and adjusts calibration parameters accordingly. This closed-loop feedback mechanism enables accurate impedance matching without requiring complex manual calibration procedures or multiple separate measurement systems.
Data Source
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AI summary
Examples provide a control circuit and a control apparatus, a radio frequency circuit and a radio frequency apparatus, a transceiver, a mobile terminal, methods and computer programs for determining calibration values for a radio frequency circuit. A control circuit (10) is configured to determine calibration values for a radio frequency circuit (100) with a transmit unit (102) coupled to an antenna (104) through an antenna tuner (106). The control circuit (10) is configured to determine the calibration values for the radio frequency circuit (100) based on at least two impedance measurements and based on at least two antenna tuner configurations.