LC Composition for Low-Loss High-Frequency Microwave Components
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Solution Overview
Problem
Existing liquid crystal (LC) materials for high-frequency components, such as microwave phase shifters, suffer from large dielectric loss, low dielectric tunability, and limited operating temperature range, which hinders the industrialization of LC-based microwave devices.
Innovation Solution
An LC composition comprising specific compounds with structural formulas (I), (II), and (III), optimized to achieve high dielectric tunability, extremely-low dielectric loss, wide nematic phase temperature range, low rotational viscosity, and large dielectric constant at low frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If existing LC materials with high birefringence (such as cyanobiphenyl or terphenyl-containing materials) are used to achieve high dielectric constant, then the dielectric constant is improved, but the dielectric loss and rotational viscosity increase significantly, resulting in slow response and low quality factor
Solution Approach 1:
The patent changes the molecular structure parameters of LC materials by introducing specific compounds with formulas (I), (II), and (III) that have optimized molecular configurations. These structural modifications enable the material to achieve high dielectric constant while maintaining low dielectric loss and rotational viscosity, directly resolving the contradiction between dielectric constant and energy loss
Solution Approach 2:
The patent creates a composite LC material system by combining multiple compounds with specific formulas and defined weight ratios (50-95% for formula I, 5-30% for formula II, and 1-10% for formula III). This composite approach allows the material to achieve balanced performance with high dielectric constant, low dielectric loss, and fast response characteristics that cannot be achieved with single compounds
2Adaptability or versatility
If LC materials with high dielectric tunability are used to improve microwave phase shifter performance, then the tuning capability is improved, but the dielectric loss increases, leading to large insertion loss and low working efficiency
Solution Approach 1:
The patent modifies the dielectric properties of LC materials through specific molecular structure design in formulas (I), (II), and (III), changing the chemical composition parameters to achieve high dielectric tunability while maintaining low dielectric loss, thereby improving both adaptability and energy efficiency simultaneously
Solution Approach 2:
The patent introduces compounds with specific local molecular structures (such as the core structures in formulas I-IV and substituent groups in formulas V-VII) that have optimized local dielectric properties. These local structural optimizations contribute to the overall high dielectric tunability while keeping dielectric loss low, resolving the contradiction between adaptability and energy loss
3Speed
If existing LC materials are used to meet fast switching requirements, then the response speed is improved, but the rotational viscosity remains high (e.g., 2100 mPa·s for bis-diphenylacetylene compounds), limiting the switching performance
Solution Approach 1:
The patent changes the physical parameters of LC materials by designing specific molecular structures in formulas (I), (II), and (III) that reduce rotational viscosity. The optimized molecular configurations and substituent groups in these formulas enable faster molecular reorientation under electric fields, achieving response speeds corresponding to rotational viscosity below 1000 mPa·s while maintaining compositional stability
Solution Approach 2:
The patent introduces specific local molecular structures (such as the core structures in formulas I-IV and substituent patterns in formulas V-VII) that have low rotational viscosity characteristics. These local structural features with optimized molecular flexibility and intermolecular interactions contribute to the overall fast response speed while maintaining the stability of the LC composition
4Temperature
If LC materials are used to expand operating temperature range, then the thermal stability is improved, but the performance at low temperatures deteriorates, limiting the practical application range
Solution Approach 1:
The patent changes the thermal properties of LC materials through specific molecular structure design in formulas (I), (II), and (III). The optimized molecular configurations, including core structures and substituent groups, lower the melting points and improve low-temperature fluidity while maintaining high-temperature stability, thereby expanding the operating temperature range and improving low-temperature performance simultaneously
Solution Approach 2:
The patent creates a composite LC system with compounds in specific weight ratios that synergistically improve thermal stability and low-temperature performance. The combination of multiple compounds with different thermal characteristics in formulas (I), (II), and (III) enables the material to maintain reliable performance across a wide temperature range, from sub-zero to high temperatures
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 LC composition exhibits high dielectric tunability, extremely-low dielectric loss, and high-quality factor at high frequencies, expands the nematic phase operating temperature range, reduces rotational viscosity, and enables a large dielectric constant at low frequencies, making it suitable for advanced high-frequency components.
Implementation Method 1
The dielectric tunability (τ) of an LC material is determined by the dielectric anisotropy (Δε) of the LC material at high frequencies and a dielectric constant (ε // ) in a parallel direction of molecules
Implementation Method 2
A dielectric constant of an LC material at a high frequency is related to the birefringence of LC
Data Source
AI summary
A liquid crystal (LC) composition and a high-frequency component including the same includes one or more selected from compounds shown in structural formula (I) and one or more selected from compounds shown in structural formula (II): where R1 is selected from alkyl with 1 to 10 carbon atoms, alkenyl with 2 to 10 carbon atoms, fluorinated alkyl, fluorinated alkenyl, and cycloalkyl; one of X1, X2, and X3 is methyl or chlorine, and the other two are hydrogen; k, m, n, and p are 0 or 1; and ring A is selected from a benzene ring, cyclohexane, and cyclohexene; where R2 and R3 each are selected from alkyl with 1 to 10 carbon atoms, alkenyl with 2 to 10 carbon atoms, fluorinated alkyl, fluorinated alkenyl, cycloalkyl, halogen, and NCS; and ring A and ring B each are selected from a benzene ring, cyclohexane, and cyclohexene.