Intelligent Reflecting Surface Subframe Driving for Phase Control
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Solution Overview
Problem
Existing radio wave reflecting devices using meta surfaces face challenges in maintaining reflection characteristics when the number of output grayscale voltages is limited, leading to reduced phase accommodation capabilities.
Innovation Solution
A driving method for a radio wave reflecting device that utilizes a time-division driving approach with multiple reflector unit cells, each equipped with a bias electrode, common electrode, and a liquid crystal layer, allowing for the transmission of voltages corresponding to different phases in subframe periods to control the reflection direction, thereby enhancing phase accommodation beyond traditional 16 levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of output grayscale voltages is limited, then the device complexity is reduced, but the phase accommodation capability deteriorates
Solution Approach 1:
The patent applies periodic action by dividing the frame period into multiple subframe periods, where different grayscale voltages are sequentially applied to the liquid crystal layer in each subframe. This time-division multiplexing approach enables the system to accommodate multiple phases using a limited set of grayscale voltage levels, effectively resolving the contradiction between device complexity and phase accommodation capability.
Solution Approach 2:
The patent utilizes the dynamic response characteristics of the liquid crystal material by applying different voltages at different time intervals within the frame period. The liquid crystal layer's ability to respond to changing voltage conditions dynamically allows the system to achieve multiple phase states from a limited number of grayscale voltage levels, improving phase accommodation without increasing device complexity.
2Reliability
If more phases are controlled, then the reflection characteristics are improved, but the device complexity increases
Solution Approach 1:
By implementing periodic voltage application across multiple subframe periods, the system achieves enhanced reflection characteristics through improved phase control. The periodic switching between different grayscale voltages allows the liquid crystal layer to achieve multiple reflection phases, improving reliability without requiring a proportional increase in the number of distinct grayscale voltage levels.
Solution Approach 2:
The patent changes the temporal parameters of voltage application rather than increasing the number of voltage levels. By modifying the timing and duration of voltage application to the liquid crystal layer across different subframe periods, the system achieves multiple phase states for improved reflection characteristics while maintaining a limited set of grayscale voltage levels, thus avoiding increased device complexity.
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 method improves reflection characteristics by enabling control over more phases, suppressing deterioration and enhancing the ability to reflect radio waves in desired directions, particularly for 5G communication standards.
Implementation Method 1
a meta surface is known that adjusts an amplitude and a phase of a high-frequency signal transmitted to each of the plurality of antenna elements and utilizes a change in a dielectric constant due to an alignment state of a liquid crystal
Implementation Method 2
utilizes a change in a dielectric constant due to an alignment state of a liquid crystal
Data Source
AI summary
A driving method for an intelligent reflecting surface, the intelligent reflecting surface includes an output signal line and a reflector unit cell electrically connected to the output signal line and having a first electrode, a second electrode, and a liquid crystal layer provided between the first electrode and the second electrode. The driving method includes transmitting a common voltage to the second electrode in a plurality of consecutive subframe periods and transmitting an output signal to the reflector unit cell through a the output signal line. The output signal includes a voltage corresponding to a phase for reflecting an incident radio wave in a predetermined direction in each adjacent subframe period among the plurality of subframe periods. Each of the reflector unit cells receives the voltage in each adjacent subframe period among the plurality of subframe periods and generates one voltage using the plurality of voltages.