Dual-Band Antenna Matching Using Variable Reactance Ratios
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Solution Overview
Problem
Mobile cellular devices face inefficiencies in communication due to changes in antenna impedance when the device context changes, particularly when operating in multiple resonant frequency bands, making it difficult to maintain efficient communication across both bands.
Innovation Solution
An apparatus comprising a matching circuit, first and second variable reactance components, a detector, and a controller that determines and adjusts optimum reactance ratios to maintain efficient communication across both frequency bands by detecting impedance changes and adapting the reactance values of the antenna element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the antenna element operates in multiple resonant frequency bands, then the communication versatility is improved, but the impedance matching becomes difficult to maintain efficiently
Solution Approach 1:
The patent employs variable reactance components that can dynamically adjust their reactance values to match the antenna impedance across different frequency bands. The first variable reactance component (series) and second variable reactance component (shunt) are controlled by a controller that receives feedback from a detector, enabling real-time adaptation of the matching circuit parameters to maintain efficient operation in both first and second resonant frequency bands.
2Adaptability or versatility
If the device context changes causing antenna impedance changes, then the adaptability to different usage scenarios is improved, but the communication efficiency deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where a detector measures the antenna impedance (or VSWR) and provides this information to a controller. The controller then adjusts the reactance values of the variable reactance components based on this feedback to optimize the impedance matching. This closed-loop control ensures that communication efficiency is maintained despite changes in device context such as user handling or environmental conditions.
3Device complexity
If a single antenna element is used for multiple frequency bands, then the device complexity is reduced, but the difficulty of maintaining efficient performance across bands increases
Solution Approach 1:
The patent changes the electrical parameters of the matching circuit by using variable reactance components whose reactance values can be adjusted. The controller modifies the reactance values of the first and second variable reactance components based on the detected frequency band and impedance conditions. This parameter adjustment allows a single antenna element to efficiently operate across multiple frequency bands without requiring multiple antenna elements, thus maintaining low device complexity while enabling effective impedance compensation.
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 solution enables adaptive tuning of the antenna element, ensuring efficient communication by compensating for impedance changes and optimizing performance in both resonant frequency bands, thereby improving signal strength and operational efficiency.
Implementation Method 1
a matching circuit; a first variable reactance component, having a first range of reactance values, and connected to the matching circuit and connectable to an antenna element operable in a first frequency band and a second frequency band
Implementation Method 2
a detector for detecting a parameter, indicative of the impedance of the apparatus, over at least a part of the first range and second range of reactance values
Data Source
AI summary
An apparatus including a matching circuit; a first variable reactance component, having a first range of reactance values, and connected to the matching circuit and connectable to an antenna element operable in a first frequency band and a second frequency band; a second variable reactance component, having a second range of reactance values, and connected to the matching circuit; a detector for detecting a parameter, indicative of the impedance of the apparatus, over at least a part of the first range and second range of reactance values; and a controller configured to determine, using information provided by the detector, optimum ratios of second reactance values to first reactance values, at a frequency in the first frequency band, and configured to select a first optimum ratio when the second frequency band is greater than the first frequency band and configured to select a second different optimum ratio when the second frequency band is less than the first frequency band.