Dual-Circuit Antenna Matching for Two-Frequency Impedance Tuning
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Solution Overview
Problem
Small electronic devices face challenges in accommodating an antenna device that can efficiently transmit and receive radio waves of multiple frequencies due to limited space and impedance mismatching issues, particularly when handling wide bands.
Innovation Solution
An adjustment method for an antenna device with an annular antenna and a dual-circuit adjustment system, where the first circuit matches resistance values and the second circuit adjusts reactance to complex conjugates at specific frequencies, ensuring impedance matching for two target frequencies while minimizing space and components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If impedance matching is performed near an intermediate frequency of multiple frequencies to handle wide bands, then the space required and number of components are reduced, but impedance mismatching issues occur and transmission/reception efficiency deteriorates
Solution Approach 1:
The adjustment circuit is divided into a first adjustment circuit and a second adjustment circuit connected in series. The first adjustment circuit handles resistance matching while the second handles reactance matching, allowing independent optimization of each function and achieving accurate impedance matching at multiple frequencies without increasing overall space requirements
Solution Approach 2:
The invention changes the approach from matching at a single intermediate frequency to matching at multiple specific frequencies by adjusting circuit constants. The first adjustment circuit sets resistance values equal to target impedance resistance at two different frequencies, while the second adjustment circuit sets reactance values to complex conjugates of target impedance reactance at those same frequencies
2Adaptability or versatility
If an antenna device is designed to transmit and receive radio waves of multiple frequencies, then the adaptability and versatility are improved, but the device complexity and space requirements increase
Solution Approach 1:
The adjustment circuit is segmented into two specialized sub-circuits: one for resistance matching and one for reactance matching. This segmentation allows each sub-circuit to be optimized for its specific function, achieving multi-frequency capability while keeping individual circuit blocks simple and manageable
Solution Approach 2:
The combined adjustment circuit system provides universal impedance matching capability across multiple frequencies (at least two different frequencies). The first and second adjustment circuits work together to handle both resistance and reactance components, creating a multi-functional system that operates efficiently across a wide frequency range
Data Source
AI summary
An adjustment method for an antenna device including an antenna, an adjustment circuit including first and second circuits connected in series with the antenna and a communication circuit connected with the adjustment circuit includes: determining constants of the first circuit such that at two frequencies, values of first resistance of first impedance as viewed from an output end of the first circuit toward the antenna each are equal to resistance of target impedance, and absolute values of first reactance of the first impedance are different from one another; and determining constants of the second circuit such that at the frequencies, while values of second resistance of second impedance as viewed from an output end of the adjustment circuit toward the antenna are kept at the values of the first resistance, values of second reactance of the second impedance each are a complex conjugate with reactance of the target impedance.