LC Composition for Low-Loss Tunable High-Frequency Components
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Solution Overview
Problem
Existing liquid crystal (LC) materials for high-frequency components have large dielectric loss, low tunability, and limited operating temperature range, which hinders the industrialization of LC-based microwave devices and requires improvements in dielectric tunability, rotational viscosity, and dielectric constant at low frequencies.
Innovation Solution
An LC composition comprising specific compounds with structural formulas (I), (II), and (III), characterized by a mass proportion of 50% to 99% and 1% to 40%, respectively, and an additive, which reduces dielectric loss and rotational viscosity while maintaining high dielectric tunability and a wide nematic phase temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If existing LC materials are used for high-frequency components, then dielectric tunability is achieved, but dielectric loss is large leading to high insertion loss
Solution Approach 1:
The patent changes the chemical composition parameters of LC materials by introducing specific molecular structures (cyclohexane rings, fluorine substituents, nitrile groups) to achieve extremely low dielectric loss (tan δ⊥ ≤ 0.008 at 19 GHz) while maintaining high dielectric tunability (τ ≥ 0.25), directly resolving the contradiction between low loss and high reliability
Solution Approach 2:
The patent creates a composite LC material system by combining multiple compounds with specific structures (compounds of formula I, II, and III) in optimized ratios, where each component contributes different properties: cyclohexane-based compounds reduce loss, fluorine substituents enhance tunability, and nitrile groups improve dielectric constant, achieving overall low insertion loss and high reliability
2Force
If high-birefringence LC materials are used to increase dielectric constant, then dielectric constant increases, but dielectric loss and rotational viscosity increase leading to slow response
Solution Approach 1:
The patent applies local quality by strategically placing specific functional groups at specific positions in the molecular structure: fluorine atoms at ortho/para positions, nitrile groups at terminal positions, and cyclohexane rings at core positions, where each local structural feature contributes selectively to dielectric constant without proportionally increasing loss or viscosity, enabling large dielectric constant (ε⊥ ≥ 2.5 at 19 GHz) with fast response (γ1 ≤ 1200 mPa·s)
Solution Approach 2:
The patent changes molecular structure parameters by selecting specific core structures (cyclohexane, benzene rings) and substituent types (fluorine, nitrile, alkyl groups) to optimize the balance between dielectric constant and rotational viscosity, achieving ε⊥ ≥ 2.5 at 19 GHz while maintaining γ1 ≤ 1200 mPa·s for fast response speed
3Adaptability or versatility
If LC materials with high dielectric tunability are used, then tuning capability improves, but operating temperature range is limited
Solution Approach 1:
The patent achieves universality by designing LC molecules with multiple functional groups that each contribute to different performance aspects: cyclohexane rings provide thermal stability and wide temperature range, fluorine substituents enhance dielectric tunability across temperatures, and nitrile groups maintain consistent dielectric properties, enabling the material to simultaneously achieve τ ≥ 0.25 and Tni ≥ 100°C with nematic phase range ≥ 100°C
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 achieves extremely-low dielectric loss, high dielectric tunability, and a large dielectric constant at low frequencies, enhancing the performance of high-frequency components such as phase shifters and phased array radars, suitable for 5G communications.
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, as shown in the following formula: Δn=ne−no=√{square root over (ε∥)}−√{square root over (ε⊥)}}
Data Source
AI summary
Disclosed are a liquid crystal (LC) composition and a high-frequency component including the same. The LC composition 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.