Folded 3D Antenna for Compact Smart Meters
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Solution Overview
Problem
As smart meters become smaller and more compact, designing an antenna with good efficiency in the smaller housing space for effective communication at low frequencies becomes a challenge, particularly in supporting frequencies like 839 and 851 MHz.
Innovation Solution
A folded antenna design is implemented, where the antenna is divided into planar and windowed radiating portions coupled at a predetermined angle, often 90 degrees, with an RF feed leg and ground leg connected to a printed circuit board, allowing for efficient resonance and reduced likelihood of shorts, thereby fitting within constrained spaces while maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna size is reduced to fit smaller smart meter housings, then the housing compactness is improved, but the antenna efficiency and resonance performance deteriorate
Solution Approach 1:
The patent transitions from a planar two-dimensional antenna layout to a three-dimensional folded structure. The antenna element is bent and folded out of the original plane, creating multiple radiating portions that extend in different spatial directions. This dimensional change allows the antenna to achieve the necessary electrical length for low frequency resonance while maintaining a compact footprint that fits within smaller smart meter housings.
Solution Approach 2:
The folded antenna structure effectively nests multiple radiating portions within a compact volume. The first and second radiating portions are folded back onto themselves and positioned in close proximity, creating a nested configuration that maximizes the use of available space while maintaining the required antenna length for efficient operation at 839 MHz and 851 MHz.
2Reliability
If a longer antenna length is used to achieve low frequency resonance, then the resonance performance is improved, but the antenna occupies more space in the housing
Solution Approach 1:
Instead of extending the antenna length in a single linear direction which would increase the occupied area, the patent folds the antenna into three dimensions. The first radiating portion and second radiating portion are arranged at an angle to each other, allowing the total electrical length to be achieved while the projected area remains compact. This spatial arrangement enables low frequency resonance without sacrificing housing space.
Solution Approach 2:
The antenna is divided into multiple segments or radiating portions that are folded and positioned in different orientations. This segmentation allows each portion to contribute to the overall resonance while the folded configuration reduces the total area occupied compared to a straight linear arrangement of the same length.
3Volume of moving object
If the antenna is folded into a compact configuration, then the housing space utilization is improved, but the manufacturing complexity increases
Solution Approach 1:
The folded antenna structure is integrated directly with the housing, eliminating the need for separate mounting brackets, supports, or additional structural components. The antenna element is configured to attach to the housing interior surface, merging the antenna structure with the housing itself and simplifying the overall device assembly despite the folded geometry.
Solution Approach 2:
The folding and bending of the antenna element is localized to specific regions, while other portions remain relatively simple and planar. This localized complexity approach allows the antenna to achieve its compact folded configuration only where necessary, while maintaining simpler structures in areas that do not require folding, thereby reducing overall manufacturing difficulty.
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 folded antenna design achieves efficient resonance and gain in the desired frequency band, providing average gain from -2.5 to -3 dBi, effectively supporting frequencies like 839 and 851 MHz within compact smart meter housings.
Implementation Method 1
The folded antenna may resonate at and is tuned for frequencies of 839 MHz and 851 MHz
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
A folded antenna is provided including an antenna having a fold therein. The fold in the antenna divides the antenna into first and second radiating portions. The first radiating portion of the folded antenna is planar and the second radiating portion has a window therein. The first and second radiating portions of the folded antenna are coupled at the fold in the antenna having a predetermined angle therebetween. Related antenna systems and meters are also provided.