Tunable Matching Network Impedance Adjustment via DC-Offset
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Solution Overview
Problem
Mobile devices face challenges in maintaining optimal antenna impedance matching due to changing environments, leading to inefficiencies in RF front-end performance and battery life, particularly due to the antenna proximity effect, which requires adjustable tunable matching networks (TMNs) for precise impedance adjustment.
Innovation Solution
A method for adjusting the impedance of a TMN by measuring output DC-offset values caused by self-mixing between the transmitter and receiver, determining the maximum DC-offset value, and tuning the TMN to achieve optimal impedance matching, utilizing tunable capacitors and a tunable bank with series and shunt capacitors to minimize losses and hardware costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed impedance matching network is used in mobile devices, then the device structure is simple and manufacturing cost is low, but the antenna impedance matching becomes ineffective due to constantly changing environment and proximity effect
Solution Approach 1:
The patent implements a tunable matching network (TMN) where the impedance matching components can dynamically adjust their values based on environmental conditions and proximity effects. The matching network transitions from a fixed configuration to a dynamically adjustable one, allowing real-time optimization of impedance matching while maintaining reasonable manufacturing costs through integrated tuning mechanisms.
Solution Approach 2:
The patent changes the impedance parameters of the matching network components (inductors, capacitors) to adapt to varying environmental conditions. By adjusting the values of these components, the system maintains optimal impedance matching despite changes in antenna proximity to other components or environmental factors, resolving the contradiction between fixed simple structure and adaptive performance.
2Reliability
If an adjustable tunable matching network is used to improve impedance matching, then the RF front-end performance is improved, but the device complexity and additional hardware costs increase
Solution Approach 1:
The patent designs the tunable matching network to serve multiple functions: impedance matching for both transmit and receive paths, environmental adaptation, and proximity effect compensation. By making the matching network multi-functional, the patent reduces the need for separate dedicated circuits for each function, thereby improving RF performance while limiting the increase in overall device complexity.
Solution Approach 2:
The patent implements self-adjustment mechanisms where the matching network automatically tunes itself based on detected environmental conditions or performance metrics. This self-service capability reduces the need for complex external control systems and manual calibration, achieving improved RF performance with minimal additional hardware complexity.
3Ease of manufacture
If traditional impedance matching methods are used, then the hardware cost is low, but the correction time for impedance mismatch is long and power consumption is high
Solution Approach 1:
The patent performs preliminary impedance matching adjustments during the initialization phase or before critical operations. By pre-tuning the matching network to anticipated conditions or performing quick calibration routines in advance, the system reduces the correction time required during actual operation, maintaining low hardware costs through efficient use of the tunable components.
Solution Approach 2:
The patent implements periodic tuning or calibration cycles where the matching network is adjusted at regular intervals or triggered by specific events. This periodic action maintains optimal impedance matching over time without requiring continuous complex control, balancing hardware cost with reduced correction time and lower power consumption compared to continuous adjustment.
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 precise self-adjustment of TMN impedance, reducing correction times and power consumption, while maintaining low additional hardware costs and minimizing manufacturing costs, thus improving RF front-end performance and battery life.
Implementation Method 1
measuring values of an output DC-offset at the receiver in the Tx mode while tuning the TMN, wherein the output DC-offset is caused by a coupling between the transmitter and the receiver
Data Source
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AI summary
The present invention relates to a method for adjusting an impedance of a tunable matching network (TMN) connected between an antenna and a transceiver front-end. The TMN comprises a receive path to provide signals from the antenna to a receiver during a receive (Rx) mode, and a transmit path to provide signals from a transmitter to the antenna during a transmit (Tx) mode. The method comprises the steps of: tuning the TMN, measuring values of an output DC-offset at the receiver in the Tx mode while tuning the TMN, wherein the output DC-offset is caused by a coupling between the transmitter and the receiver; determining a maximum value of the output DC-offset from the measured output DC-offset values; and adjusting the impedance of the TMN by tuning the TMN to the output DC-offset maximum value.