Remote Antenna Impedance Measurement via Automatic Tuner
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for measuring antenna impedance at the feed point are cumbersome and unreliable, especially when the antenna is remote from the transmitter, as they require disconnecting the antenna and using low-power analyzers that can be swamped by local RF signals, making it difficult to obtain accurate measurements under actual operating conditions.
Innovation Solution
An automatic antenna tuner is inserted between the transmitter and the transmission line, which automatically adjusts capacitive and inductive components to achieve a minimum SWR, allowing for the direct calculation of antenna input impedance using the tuner's impedance values, transmission line length, and velocity factor, enabling remote measurement at full power without disconnecting the antenna.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a low-power antenna analyzer is used to measure antenna impedance, then the measurement can be performed with minimal power consumption, but the measurement precision deteriorates because the low-power signal is swamped by local RF signals
Solution Approach 1:
The patent introduces an automatic antenna tuner as an intermediary device between the transmitter and the antenna. The tuner measures the complex impedance at its input terminals using the full-power transmitter signal, then calculates the antenna feed point impedance by compensating for the transmission line effects. This mediator approach allows accurate measurement without using a low-power analyzer that would be swamped by RF signals.
Solution Approach 2:
The patent replaces the mechanical/physical approach of using a low-power antenna analyzer with an electrical calculation approach. Instead of directly measuring with a vulnerable low-power device, the system uses the robust full-power signal already present in the system, measures impedance electrically at the tuner, and computes the desired value through mathematical compensation for transmission line effects.
2Measurement precision
If the antenna is disconnected from the transmitter to perform impedance measurement, then the measurement can be isolated from other RF signals, but the ease of operation deteriorates due to the complicated measurement procedure
Solution Approach 1:
The automatic antenna tuner performs the impedance measurement function on its own while remaining connected to the antenna and transmitter. The tuner's microprocessor automatically measures the complex impedance at its input, calculates the antenna feed point impedance, and displays the result without requiring technician intervention to disconnect components or set up special measurement configurations.
Solution Approach 2:
The automatic antenna tuner is designed to perform multiple functions: it serves as an impedance matching device for normal operation and simultaneously functions as an impedance measurement device. This multi-functionality eliminates the need for separate measurement equipment and complex disconnection procedures, allowing the same device to handle both operational and diagnostic tasks.
3Ease of operation
If an automatic antenna tuner is used to remotely measure antenna impedance, then the ease of operation improves by eliminating disconnection requirements, but the device complexity increases
Solution Approach 1:
The automatic antenna tuner acts as an intermediary that bridges the gap between the transmitter and the remote antenna. It incorporates a microprocessor-based impedance measurement system that automatically measures the complex impedance at its input terminals and calculates the antenna feed point impedance by compensating for transmission line effects, providing remote measurement capability without requiring additional complex equipment at the antenna location.
Solution Approach 2:
The patent replaces complex physical measurement procedures with electrical calculations performed by a microprocessor. Instead of requiring physical disconnection and manual measurement setups, the system uses the existing full-power RF signal, measures impedance electrically at the tuner location, and computes the antenna impedance through mathematical compensation for transmission line effects, thereby managing complexity through software rather than hardware complexity.
4Measurement precision
If measurements are performed at full transmitter power, then the measurement precision improves by avoiding signal swamping, but the loss of energy increases due to continuous full-power operation
Solution Approach 1:
The system maintains continuous full-power operation to the antenna through the automatic antenna tuner. The tuner measures the complex impedance using the full-power transmitter signal that is already being transmitted, eliminating the need to reduce power or interrupt service for measurements. This continuous operation ensures both measurement precision and uninterrupted useful action.
Solution Approach 2:
The automatic antenna tuner performs impedance measurements using the full-power signal already present in the system during normal operation. The tuner's microprocessor automatically captures the complex impedance data from the full-power signal, calculates the antenna feed point impedance, and provides readings without requiring separate low-power measurement operations, thereby eliminating energy loss associated with switching between power levels.
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 method provides a simplified and accurate remote measurement of antenna input impedance under actual operating conditions, eliminating the need for low-power analyzers and ensuring measurements are not affected by local RF signals, thus improving the efficiency and reliability of antenna performance monitoring.
Implementation Method 1
An automatic antenna tuner is inserted between the transmitter and the transmission line, which automatically adjusts capacitive and inductive components to achieve a minimum SWR
Implementation Method 2
automatically adjusts capacitive and inductive components
Implementation Method 3
automatically adjusts capacitive and inductive components
Implementation Method 4
allowing for the direct calculation of antenna input impedance using the tuner's impedance values
Data Source
AI summary
A system for remotely measuring antenna input impedance utilizing an automatic antenna tuner in which, for any tuner, the tuner input impedance may be established by the values of the components in the circuit at the time that the SWR is at a minimum, with these values being automatically available in terms of the components that are switched in to achieve low SWR. Once having established the input impedance to the tuner, the complex conjugate of the tuner input impedance yields the antenna input impedance, with antenna input impedance sensed at full power at a position remote from the antenna input.