Galvanic Isolation Mechanism for Planar Circuit
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Solution Overview
Problem
Existing galvanic isolation mechanisms in radar-based level measurement systems face challenges in providing effective DC blocking while minimizing transmission losses and reflections, particularly in harsh environmental conditions such as large temperature changes, high humidity, and dust.
Innovation Solution
A galvanic isolation mechanism for a planar circuit formed on a two-sided substrate, incorporating a coplanar waveguide, microstrip line, and a microwave DC block, which blocks DC signals while allowing AC microwave signals to pass through, with a ground plane underlying at least a portion of the coplanar waveguide and microstrip line to ensure effective isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If galvanic isolation mechanisms are implemented to block DC signals, then DC blocking is achieved, but transmission losses and reflections increase
Solution Approach 1:
The patent introduces an intermediary structure (isolation component with conductive elements and dielectric material) between the process connection and electronic circuitry to achieve DC blocking while maintaining AC signal transmission. This intermediary structure allows the system to block DC signals for safety while minimizing transmission losses through proper electromagnetic coupling design.
Solution Approach 2:
The patent utilizes parameter changes in the isolation component, specifically varying the dielectric constant and conductivity of materials at different frequencies. The isolation component is designed to have different electrical characteristics for DC versus AC signals, allowing DC blocking while maintaining low loss for microwave frequency signals through controlled impedance matching.
2Reliability
If galvanic isolation mechanisms are implemented to block DC signals, then DC blocking is achieved, but signal reflections increase
Solution Approach 1:
The isolation component acts as an intermediary that gradually transitions the impedance between the coaxial cable and electronic circuitry, reducing sudden impedance mismatches that cause reflections. The structured arrangement of conductive elements and dielectric material creates a smooth impedance transformation path for AC signals while maintaining DC isolation.
Solution Approach 2:
The isolation component employs parameter changes in its electromagnetic properties across different frequencies, with the dielectric material and conductive elements configured to maintain controlled impedance for microwave signals. This frequency-dependent parameter variation allows the structure to minimize reflections at operating frequencies while blocking DC.
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
The solution effectively provides galvanic isolation with reduced transmission losses and reflections, ensuring reliable operation in challenging environments by blocking DC signals and allowing AC signals to pass through, thus maintaining the integrity of the measurement system.
Implementation Method 1
the microwave DC block allows AC signals to pass through
Implementation Method 2
a ground plane underlying at least a portion of the coplanar waveguide and microstrip line to ensure effective isolation
Data Source
AI summary
A mechanism is provided for coupling a coaxial cable to a planar circuit to provide galvanic isolation between the coaxial cable and the planar circuit while providing low transmission loss and reflections between the coaxial cable and the circuit. The mechanism comprises a co-planar waveguide coupled to the coaxial cable, a microstrip line connected to the circuit, a galvanic isolation component and a ground plane. The co-planar waveguide, the microstrip line and the galvanic isolation component are formed on one side of a two-sided substrate. The ground plane is formed on the other side of the substrate and underlies at least a portion of the co-planar waveguide to form a grounded co-planar waveguide. The ground plane includes a notch underlying a portion of the co-planar waveguide to provide a transition region from the co-planar waveguide to the grounded co-planar waveguide.