Network Analyzer Calibration Device Using Series Transistor Loads
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Solution Overview
Problem
Current electronic calibration devices for network analyzers are complex and require a large number of transistors, limiting their upper-frequency threshold and increasing the complexity and time required for calibration, especially for multi-port analyzers.
Innovation Solution
A calibration device with a minimal number of components, utilizing a series connection of first and second transistors as adjustable loads, which can be set using gate voltage or base current, and a thermostatic control to maintain constant temperature, allowing for rapid and accurate calibration across multiple ports without the need for separate terminations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate terminations are provided for each port, then calibration accuracy is improved, but device complexity and chip area increase significantly
Solution Approach 1:
The patent implements a universal calibration circuit that can calibrate multiple ports (up to 8 ports) using a single integrated circuit structure. The same calibration circuit is reused for each port through sequential connection, eliminating the need for separate termination components for each port. This multi-functional approach maintains calibration accuracy while dramatically reducing device complexity and chip area.
Solution Approach 2:
The patent merges the calibration functions for multiple ports into a single integrated calibration circuit. Instead of providing separate terminations and calibration components for each port, the invention combines all calibration functionality into one shared circuit that can be sequentially connected to different ports, reducing the overall number of components and simplifying the device structure.
2Reliability
If more transistors are used to increase frequency threshold, then upper-frequency threshold is improved, but device complexity and chip area increase
Solution Approach 1:
The calibration circuit uses a minimal set of transistors (first and second transistors per port) that serve multiple functions: switching, signal routing, and calibration. These transistors are reused across different ports and calibration modes, achieving high frequency threshold performance without requiring a proportional increase in transistor count for each additional port.
Solution Approach 2:
The patent employs dynamically controllable transistors with adjustable gate voltages or base currents to optimize performance across different frequency ranges. The transistors can be adjusted to operate at optimal points for different frequency thresholds, allowing the same hardware configuration to maintain high frequency performance without requiring additional transistors for each frequency range.
3Measurement precision
If calibration device is connected successively to different ports, then complete calibration is achieved, but calibration time increases
Solution Approach 1:
The calibration circuit is pre-configured with all necessary calibration standards (open, short, match, through) and control logic integrated into a single device. This preliminary preparation allows the calibration to proceed through rapid sequential port connections without requiring intermediate setup or reconfiguration, minimizing the time lost during port-to-port transitions while ensuring complete calibration coverage.
4Ease of operation
If screw connections are used for port connections, then physical connection is achieved, but connection errors and reflection sites increase
Solution Approach 1:
The patent replaces mechanical screw connections with integrated electrical connections through the unified calibration circuit design. The calibration device provides standardized electrical interfaces that connect directly to network analyzer ports, eliminating mechanical assembly steps and associated errors such as improper tightening or created reflection sites, while maintaining reliable physical connection.
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 configuration reduces the size of the calibration device, increases the upper-frequency threshold, and accelerates the calibration process while minimizing errors, making it suitable for network analyzers with several ports and maintaining accuracy across varying temperatures.
Implementation Method 1
Moreover, an advantage is achieved if the calibration device provides a thermostatic control, so that the calibration device can be heated to a constant temperature. As a result, the temperature-dependent properties of the transistors are taken into consideration and compensated in an improved manner, because the calibration circuit always provides the same temperature.
Implementation Method 2
A further advantage is achieved if the adjustable load of the first transistor can be set by applying a gate voltage or a base current. In this manner, the operating point of the transistor can be matched in a very simple manner. This occurs very rapidly, so that the calibration procedure can be concluded very quickly.
Data Source
AI summary
A calibration device for a network analyzer with several ports provides a calibration circuit, which is connected in each case via a terminal port respectively to one of the several ports of the network analyzer. A first transistor and a second transistor are connected in series to each terminal port. In this context, both transistors are connected by their common connection to the terminal port. The first transistor and/or the second transistor is operated as an adjustable load.