Liquid Crystal Antenna Impedance Matching
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Solution Overview
Problem
The challenge in manufacturing antennas on glass substrates is the difficulty in achieving accurate impedance matching due to poor sticking accuracy, which leads to echo phenomena and increased standing wave ratios, especially when compared to conventional printed circuit boards (PCBs).
Innovation Solution
The solution involves a structure comprising a first and second substrate with a microstrip line and a liquid crystal layer between them, where drive electrode assemblies control the liquid crystal molecules to adjust the characteristic impedance of the microstrip line, matching it with the input impedance of the antenna feeder line, thereby reducing standing wave ratios without the need for additional components like variable inductors or capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If copper foil is stuck to glass substrate to manufacture antenna, then manufacturing process is simplified, but sticking accuracy is poor causing echo phenomenon
Solution Approach 1:
The patent changes the electrical parameter (characteristic impedance) of the microstrip line by adjusting the orthographic projection overlap between the microstrip line and first antenna electrode. By varying the overlapping area, the characteristic impedance can be tuned to achieve impedance matching with the antenna input impedance, thereby resolving the echo issue without requiring high sticking accuracy
Solution Approach 2:
The patent introduces a liquid crystal layer that can dynamically adjust its refractive index in response to voltage changes. This dynamic adjustment capability allows the characteristic impedance of the microstrip line to be tuned after assembly, compensating for any sticking errors and maintaining impedance matching without requiring precise initial positioning
2Manufacturing precision
If variable inductors or capacitors are added to adjust impedance, then impedance matching is improved, but device complexity increases
Solution Approach 1:
The liquid crystal layer serves multiple functions: it acts as both the antenna substrate medium and the impedance tuning mechanism. By adjusting the liquid crystal's refractive index, the system can achieve impedance matching without requiring separate variable inductors or capacitors, thus reducing component quantity while maintaining matching accuracy
Solution Approach 2:
The patent merges the impedance adjustment function into the existing microstrip line structure by utilizing the liquid crystal layer's variable refractive index. This integration eliminates the need for separate tuning components, combining the transmission line and impedance matching functions into a single unified structure
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 allows for impedance matching without the complexity of adding components like variable inductors or capacitors, simplifying the manufacturing process and reducing costs by using a liquid crystal panel manufacturing process, which does not require punching holes in the glass substrate.
Implementation Method 1
The at least one drive electrode assembly is configured to achieve impedance matching of the antenna by controlling liquid crystal molecules of the liquid crystal layer to deflect
Data Source
AI summary
An antenna includes: a first substrate and a second substrate; a first antenna electrode is disposed on a side of the first substrate away from the second substrate; a second antenna electrode is disposed on a side of the second substrate away from the first substrate and a microstrip line is disposed on a side of the second substrate close to the first substrate; a liquid crystal layer is disposed between the first substrate and the second substrate; at least one drive electrode assembly is disposed between the first substrate and the second substrate. The at least one drive electrode assembly is configured to achieve impedance matching of the antenna by controlling liquid crystal molecules of the liquid crystal layer to deflect.