Liquid Crystal Phased Array Driving for Stable Phase Retardation
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Solution Overview
Problem
Existing phased array antennas and radio wave reflecting devices using liquid crystals face challenges in maintaining consistent phase retardation between adjacent elements, leading to deviations in emission and reflection directions over time due to burn-in effects and limited control over the phase of radio waves.
Innovation Solution
The method involves a phased array antenna and radio wave reflecting device configuration with liquid crystal layers sandwiched between substrates, where phase control electrodes and patch electrodes are driven with alternating voltages to maintain consistent phase retardation, suppressing burn-in by periodically reversing polarity and adjusting voltage levels, ensuring phase coherence over extended periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If liquid crystals are used in phased array antenna elements to control phase, then phase adjustment capability is improved, but burn-in effects occur causing phase inconsistency over time
Solution Approach 1:
The patent applies periodic action by alternately applying first and second voltages with different polarities to adjacent antenna elements in time sequence. This periodic voltage reversal prevents burn-in effects in liquid crystals by periodically resetting their molecular orientation, thereby maintaining phase consistency across all elements over extended periods while preserving phase adjustment capability.
2Adaptability or versatility
If liquid crystals are used in radio wave reflecting device to control reflection phase, then reflection direction control is improved, but burn-in effects cause phase inconsistency
Solution Approach 1:
The patent applies periodic action by alternately applying first and second voltages with different polarities to adjacent reflection control portions in time sequence. This periodic voltage reversal prevents burn-in effects in liquid crystals by periodically resetting their molecular orientation, thereby maintaining phase consistency across all reflection control portions over extended periods while preserving reflection direction control capability.
3Device complexity
If conventional voltage application method is used, then device structure is simple, but phase control precision deteriorates due to burn-in
Solution Approach 1:
The patent implements periodic voltage application with alternating polarities to adjacent elements, which prevents burn-in effects and maintains liquid crystal molecular orientation consistency. This approach preserves phase control precision over time without requiring complex additional hardware, as it utilizes the existing voltage application structure with a time-sequenced control scheme.
4Adaptability or versatility
If liquid crystal phase shifters are used in phased array antenna, then directional control capability is improved, but directional deviation occurs over time due to burn-in
Solution Approach 1:
The patent applies periodic voltage reversal to adjacent antenna elements, which prevents burn-in effects in liquid crystal phase shifters by periodically resetting their molecular orientation. This maintains consistent phase relationships between elements, thereby preserving directional control accuracy and preventing beam pointing deviation over extended operational periods.
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 configuration effectively controls the phase of radio waves, preventing burn-in and maintaining directional consistency, enhancing the reliability and longevity of phased array antennas and radio wave reflecting devices, particularly in high-frequency applications like 5G communication.
Implementation Method 1
it is necessary to adjust the dielectric constant of the liquid crystals such that a retardation between the high-frequency signals input to the adjacent antenna elements is constant
Implementation Method 2
a phase shifter using liquid crystals has been developed
Implementation Method 3
a radio wave reflecting device that is capable of controlling a reflection direction of a radio wave by using liquid crystals has been also considered
Data Source
AI summary
According to one embodiment, a method of driving a phased array antenna, includes applying voltages to phase control electrodes in a first period such that radio waves to be emitted from antennas are in a same phase in a first emission direction, and applying the voltages to the phase control electrodes in a second period such that the radio waves to be emitted from the antennas are held in the same phase in the first emission direction. An absolute value of the voltage applied in the second period is different from an absolute value of the voltage applied in the first period, in each of the phase control electrodes.