RF Tester Extension Circuit Calibrates Source Reflection Coefficient
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In RF port calibration for ATE systems, the use of additional switches in a fan-out structure degrades RF performance and introduces mismatch errors due to non-50Ω impedance mismatches, leading to increased calibration time and reduced accuracy.
Innovation Solution
A tester with an extension circuit that includes a TX port, a termination switch, and a calibration device with terminations, where one termination is a power sensor, allowing for the measurement of reflection coefficients to determine the source reflection coefficient, thereby calibrating the source power and reducing mismatch errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional switches are used in a fan-out structure to provide multiple RF ports, then the number of RF ports is increased, but RF performance is degraded due to impedance mismatches
Solution Approach 1:
The patent changes the impedance parameter from the conventional 50Ω to a non-50Ω impedance (e.g., 75Ω or other optimized values) to reduce mismatch errors in the fan-out structure. This parameter change allows for better RF performance across multiple ports by optimizing the impedance matching characteristics of the connection circuit and power sensor, thereby resolving the contradiction between providing multiple RF ports and maintaining RF performance.
2Measurement precision
If absolute power measurement at each port over frequency is performed, then accurate power calibration is achieved, but calibration time is excessively long
Solution Approach 1:
The patent performs preliminary characterization of the connection circuit's frequency-dependent insertion loss and mismatch properties before actual calibration. By pre-measuring and storing these parameters, the system can quickly apply correction factors during calibration without performing time-consuming full-sweep measurements at each port, thus achieving accurate calibration with reduced time.
Solution Approach 2:
The patent introduces an intermediary measurement approach where a single power sensor measures power at one port, and the results are transformed to other ports using pre-characterized path loss data. This intermediary method avoids direct measurement at each port while still achieving accurate calibration through mathematical transformation based on the known frequency response of the connection circuit.
3Productivity
If a power sensor is used with non-50Ω impedance, then calibration speed is improved, but mismatch error increases due to impedance mismatch
Solution Approach 1:
The patent changes the impedance parameter of the power sensor from the conventional 50Ω to a non-50Ω impedance that better matches the connection circuit. This parameter change reduces the mismatch error between the power sensor and the fan-out structure, thereby improving power measurement accuracy while maintaining the fast calibration speed enabled by the single-sensor approach.
Solution Approach 2:
The patent replaces direct physical impedance matching (mechanical/electrical connection optimization) with a systematic approach using pre-characterized frequency response data and mathematical transformation. Instead of physically optimizing each connection for perfect matching, the system uses measured insertion loss data to computationally correct for mismatches, achieving high accuracy without complex physical adjustments.
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 approach simplifies the calibration process, reduces calibration time, and improves RF performance by determining the source reflection coefficient using measured reflection coefficients, enabling accurate power calibration across multiple RF ports without external equipment.
Implementation Method 1
one of the terminations is a power sensor, which is configured to measure the power of the source and measuring device at the TX port
Implementation Method 2
the source and measuring device is configured to measure one or more reflection coefficients at the TX port for the one or more terminations provided by the calibration device including the reflection coefficient for the power sensor
Data Source
AI summary
A tester including a source and measuring device and a TX port connected to the source and measuring device is provided. The tester is configured to determine a source reflection coefficient using an extension circuit. The extension circuit includes a TX port connectable to the source and measuring device, a termination switch and a calibration device providing one or more terminations, wherein each of the terminations is individually connectable to the TX port by the termination switch, wherein one of the terminations is a power sensor. The source and measuring device is configured to measure one or more reflection coefficients at the TX port for the one or more terminations provided by the calibration device including the reflection coefficient for the power sensor. The tester is configured to determine the source reflection coefficient based on the one or more measured reflection coefficients including the measured reflection coefficient for the power sensor.