Active Directional Structure for VNA Signal Isolation
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Solution Overview
Problem
Conventional vector network analyzers (VNAs) face challenges with high noise and low isolation due to passive directional elements, while narrowband passive systems are limited by bandwidth constraints.
Innovation Solution
An active directional structure for VNAs is introduced, comprising a generator port, a device-under-test (DUT) port, a measurement port, and a reference port, with first and second converters that utilize transistor circuits to generate and process signals, enabling ultra-wideband operation with lower noise and higher port isolations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If passive directional elements (bridges) are used in conventional VNAs, then wideband coupling is achieved, but high noise and low isolation occur
Solution Approach 1:
The patent replaces passive mechanical bridge structures with active transistor-based directional elements. The active directional structure uses transistor switches to achieve signal separation and coupling, substituting the conventional passive resistive bridge architecture. This substitution enables ultra-wideband operation while improving noise performance and port isolation through active control mechanisms.
Solution Approach 2:
The patent changes the operating parameters and architecture from passive to active systems. By using transistor circuits with controlled switching states, the system can dynamically adjust signal paths and improve isolation between ports. The active elements allow for better control of signal flow, achieving both wideband operation and high isolation simultaneously.
2Reliability
If narrowband passive directional elements (couplers) are used, then lower noise is achieved, but bandwidth limitations occur
Solution Approach 1:
The patent introduces dynamic control through transistor switches that can operate across a wide frequency range. The active directional structure uses controllable switching elements that adapt to different signal conditions, enabling the system to maintain low noise performance while operating across ultra-wideband frequencies. The dynamic nature of transistor switches allows for flexible signal routing without the bandwidth constraints of passive narrowband couplers.
3Adaptability or versatility
If active directional structure with transistor circuits is used, then ultra-wideband operation and lower noise are achieved, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into integrated active directional structures. The transistor-based circuits combine signal generation, switching, and directionality control in unified circuits that replace multiple separate passive components. This integration reduces the overall number of discrete elements while achieving superior performance, thereby managing complexity through functional consolidation.
Data Source
AI summary
The present disclosure relates to an active directional structure for a test and/or measurement system, comprising: a generator port configured to receive a generator signal; a DUT port arranged for directly or indirectly connecting a DUT; a measurement port configured to output a measurement signal; and a reference port configured to output a reference signal. The active directional structure further comprises: a first converter which is configured to generate a test signal and the reference signal based on the generator signal; and a second converter which is configured to: generate the measurement signal based on the test signal, a reflected signal from the DUT and the reference signal; wherein the first converter and/or the second converter comprise a respective transistor circuit.