VNA Calibration Unit With Isolation Circuit For Multi-Port Testing
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Solution Overview
Problem
Current vector network analyzer (VNA) calibration methods require frequent disconnection and reconnection of calibration units, leading to increased calibration time and connector wear, especially when performing transmission tracking and load match measurements across multiple ports over a wide frequency band.
Innovation Solution
A calibration unit and system that integrates a calibration circuit providing open, short, and match standards, along with an isolation circuit, allowing for simultaneous connection of multiple calibration units to reduce the need for manual reconnection and enable continuous calibration without disconnecting from the device-under-test, utilizing switching units and distribution units to manage connections efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration units are disconnected and reconnected during calibration routine, then transmission tracking and load match measurements can be performed, but calibration time increases and connector wear increases
Solution Approach 1:
The calibration unit is segmented into separate functional modules: a calibration circuit providing calibration standards (open, short, match) and an isolation circuit with through connection. This segmentation allows different calibration measurements to be performed through dedicated paths without requiring physical disconnection and reconnection of the entire calibration setup.
Solution Approach 2:
The isolation circuit acts as an intermediary element between the calibration circuit and the device-under-test. It provides a stable through connection that maintains signal path continuity while enabling calibration measurements to be performed without altering the overall connection topology, thereby reducing calibration time and connector wear.
2Measurement precision
If multiple calibration units are connected to multiple DUT ports, then comprehensive calibration can be performed, but the disconnecting process takes more time
Solution Approach 1:
The calibration unit is designed as a universal module that can be connected to multiple DUT ports simultaneously. Each calibration unit contains both calibration standards and a through connection, enabling it to serve multiple calibration functions (reflection calibration, transmission tracking, load match) across different ports without requiring separate dedicated equipment for each function.
Solution Approach 2:
The isolation circuit with through connection is pre-configured and permanently connected, eliminating the need for preliminary disconnection actions before performing transmission tracking and load match measurements. This preliminary setup allows calibration measurements to be performed continuously without interrupting the connection to the device-under-test.
3Measurement precision
If calibration is performed over wide frequency band with high resolution, then measurement accuracy is improved, but each calibration measurement takes more time
Solution Approach 1:
The isolation circuit enables continuous signal transmission through the calibration unit during calibration measurements. This continuous action allows the VNA to perform high-resolution swept frequency measurements without interruption, maintaining measurement accuracy across wide frequency bands while minimizing the time required by eliminating the need to disconnect and reconnect calibration units between measurements.
Data Source
AI summary
The present disclosure relates to a calibration unit for a vector network analyzer (VNA). The calibration unit comprises a calibration circuit which is configured to provide the calibration standards open, short and match; and an isolation circuit. The calibration circuit comprises a first port which is arranged for being connected to a port of the VNA, a second port which is arranged for being connected to a device-under-test (DUT), and a third port which is connected to a first port of the isolation circuit; and the isolation circuit comprises a second port which is arranged for being connected to one or more further calibration units.