Impedance Matching Network Using Unun Transformers
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Solution Overview
Problem
Existing line flatteners are complex and costly, using discriminator tuning to achieve coarse impedance matching, which is inefficient and not suitable for modern radio systems requiring precise impedance matching across a wide range of standing wave ratios.
Innovation Solution
A passive broadband impedance matching network with a watt meter, unbalanced to unbalanced transformers, and a microprocessor for automatic tuning, which iteratively determines the optimal transformer and coaxial transmission line configuration to minimize standing wave ratio, reducing the complexity and cost while achieving precise impedance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If discriminator tuning is used to achieve coarse impedance matching, then impedance matching capability is provided, but device complexity and cost increase significantly
Solution Approach 1:
The patent extracts and removes the complex discriminator tuning subsystem from the impedance matching network, replacing it with simple unun transformers and coaxial transmission lines. This eliminates the need for complex electronic measurement and control hardware while maintaining impedance matching functionality through passive component selection.
Solution Approach 2:
The patent replaces expensive, complex electronic discriminator tuning components with inexpensive passive components (unun transformers and coaxial cables). These simple components achieve the same impedance transformation function without requiring complex electronics, microprocessors, or expensive measurement subsystems.
2Loss of energy
If passive electronic circuit is used for impedance transformation, then power transfer efficiency is improved, but measurement precision of impedance matching deteriorates
Solution Approach 1:
The patent incorporates a watt meter that provides feedback on forward and reflected power measurements. The microprocessor uses this feedback information to calculate SWR and determine which unun configuration provides the best impedance match, enabling precise measurement and optimization of power transfer efficiency.
Solution Approach 2:
The patent replaces complex mechanical discriminator tuning mechanisms with an automated electronic system using solid-state switches, a microprocessor, and software control. This substitution enables more precise and repeatable impedance matching measurements while maintaining the benefits of passive component-based power transfer.
3Measurement precision
If automated tuning with microprocessor is implemented, then impedance matching precision is improved, but device complexity increases
Solution Approach 1:
The microprocessor serves multiple functions: it controls the switching of unun transformers, reads the watt meter measurements, calculates SWR, determines the optimal configuration, and stores results in memory. This multi-functionality consolidates what could be multiple separate control circuits into a single integrated component, reducing overall system complexity while maintaining precision.
Solution Approach 2:
The system performs self-testing and self-configuration by automatically measuring forward and reflected power, calculating SWR, and selecting the optimal unun configuration without external intervention. The microprocessor autonomously controls the switching matrix and stores the results, eliminating the need for manual tuning or external calibration equipment.
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 effectively reduces the standing wave ratio from 4:1 to 1.5:1 or less, ensuring efficient power transfer and reducing the need for complex electronic subsystems, thereby improving the efficiency and reducing the cost of impedance matching in radio systems.
Implementation Method 1
A first unbalanced to unbalanced transformer ('first unun') with an impedance ratio of N:1 is selectively coupled in series with the watt meter
Data Source
AI summary
An impedance matching network between a transmitter and an antenna. The impedance matching network comprises of a watt meter coupled to the transmitter for measuring a standing wave ratio (“SWR”). A first unbalanced to unbalanced transformer (“first unun”) with an impedance ratio of N:1 is selectively coupled in series with the watt meter. A microprocessor is coupled to the watt meter for determining iteratively whether the first unun lowers the standing wave ratio (“SWR”) in response to switching the first unun in and out of a series connection with the antenna.