Reflectarray Two-Dimensional Phase Control via Mushroom Structures
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Solution Overview
Problem
Existing reflectarrays face limitations in reflecting incident waves into desired directions other than specular reflections, restricting design freedom and degrading reflected wave quality due to the requirement that all waves remain in the same plane, and are unable to vary reflection phases in both x-axis and y-axis directions effectively.
Innovation Solution
A reflectarray design utilizing mushroom-like structures with varying gap sizes and patch lengths, allowing for two-dimensional phase control and reflection phase variations across elements to direct incident waves into desired directions, including multiple beams, by adjusting the reflection phases of elements in both the x-axis and y-axis directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a reflectarray is designed with elements arranged in one direction (x-axis or y-axis) with total reflection phase of 360 degrees, then the structure is simplified, but the reflection phase cannot be varied in both x-axis and y-axis directions, restricting the ability to reflect incident waves in desirable directions
Solution Approach 1:
The patent transitions from one-dimensional phase control (varying phase in only x-axis or y-axis) to two-dimensional phase control by arranging elements in a grid pattern and independently controlling phase variation in both x-axis and y-axis directions. This dimensional expansion enables reflection of incident waves in any desirable direction within the plane, resolving the contradiction between structural simplicity and directional control versatility.
Solution Approach 2:
The patent employs parameter changes by adjusting the gap sizes between adjacent elements in the array. By varying the gap dimensions, the reflection phase of each element can be controlled independently in both x and y directions, enabling precise two-dimensional phase control without increasing overall structural complexity significantly.
2Ease of manufacture
If all incident waves, specular reflected waves, and reflected waves in desired direction are constrained to the same plane, then the design follows conventional specular reflection principles, but the reflected wave in the desired direction is degraded due to specular reflection interference
Solution Approach 1:
The patent introduces asymmetry by allowing the reflected wave in the desired direction to exist in a different plane from the incident wave and specular reflected wave. By breaking the conventional coplanar constraint, the design achieves asymmetric wave configuration that eliminates specular reflection interference, thereby improving reflected wave quality while maintaining design feasibility.
3Ease of manufacture
If the reflectarray uses fixed gap sizes between elements, then the manufacturing process is simplified, but the reflection phase cannot be varied across different elements to achieve directional control
Solution Approach 1:
The patent applies local quality by varying the gap sizes between adjacent elements at different positions in the array. Each element's gap dimension is locally adjusted to achieve the specific reflection phase required for directional control. This localized variation enables precise phase control across the array while maintaining a relatively simple manufacturing process that only requires controlling gap dimensions.
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
Enables the reflection of incident waves into desired directions with improved freedom in design and enhanced reflected wave quality by allowing phase variations in both axes, achieving strong reflection in specific directions while minimizing unwanted lobes.
Implementation Method 1
When a reflectarray reflects an incident wave, the reflectarray can cause the incident wave to reflect in a desired direction as well as a direction of specular reflection
Data Source
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AI summary
A reflectarray reflects an incident wave in a desired direction, and the reflectarray includes a plurality of elements arranged in a first direction and in a second direction perpendicular to the first direction. The elements reflect the incident wave. A phase of a reflected wave by one element among the plurality of elements differs from a phase of the reflected wave by an element adjacent to the one element in the first direction by a predetermined value, and the phase of the reflected wave by the one element is equal to a phase of the reflected wave by an element adjacent to the one element in the second direction. Gap sizes between patches of a predetermined plural number of elements arranged in the first direction vary from a smallest value to a largest value. Here, an oblique TM incidence is utilized at a spurious resonance frequency.