F-Shaped Antenna for Sealed Subsurface Utility Enclosures
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Solution Overview
Problem
Existing automatic meter reading (AMR) systems for subsurface utility enclosures have limitations in signal transmission distance, typically reaching only up to 0.5 miles due to the compactness requirements and capacitive effects of dielectric materials on antennas.
Innovation Solution
A compact antenna design featuring an F-shaped element and an L-shaped ground plane, both made of conductive metallic sheets, optimized for resonant operation at 450-470 MHz, allowing for extended signal transmission up to 1 mile without increasing the assembly's height or size, and using non-contact encapsulation to prevent capacitive interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the antenna is enclosed in a sealed housing with dielectric encapsulant for moisture protection, then reliability is improved, but signal transmission distance deteriorates due to capacitive effects
Solution Approach 1:
The patent extracts the antenna from direct contact with the dielectric encapsulant by providing a dedicated antenna compartment separated from the battery compartment. The encapsulant is confined to the battery compartment, eliminating the capacitive interference that would otherwise affect the antenna's signal transmission capability while maintaining moisture protection for the electronic components.
Solution Approach 2:
The patent introduces an intermediate barrier (interior barrier) that physically separates the antenna compartment from the battery compartment. This barrier acts as a mediator that allows the encapsulant to protect the batteries and circuit board from moisture while preventing the encapsulant from contacting the antenna, thus resolving the contradiction between protection and signal transmission.
2Ease of operation
If the antenna assembly is made compact to fit in subsurface enclosure, then ease of installation is improved, but signal transmission distance deteriorates
Solution Approach 1:
The patent utilizes three-dimensional spatial arrangement by creating an L-shaped ground plane configuration and positioning the F-shaped antenna element vertically within the compact housing. This dimensional optimization allows the antenna to achieve sufficient signal transmission distance (up to 1 mile) while maintaining a compact footprint that fits within the subsurface utility enclosure constraints.
Solution Approach 2:
The patent segments the housing into distinct compartments (antenna compartment and battery compartment) with specific functions. The antenna compartment is optimized for signal transmission with appropriate spacing and grounding, while the battery compartment handles power supply. This segmentation allows each component to be optimized for its specific function without compromising the other.
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 antenna design enhances signal transmission range to 1 mile while maintaining a compact and moisture-protected transmitter assembly, ensuring reliable data collection in subsurface utility enclosures.
Implementation Method 1
The antenna is dimensioned such that it is tuned to a resonant frequency in a preferred range from 450 Mhz to 470 Mhz
Data Source
AI summary
An antenna (14, 15) for installation in a subsurface ground enclosure has an F-shaped radiating element (15) having a rectangular strip (15c) disposed on edge and two spaced apart bars (15a, 15b) disposed substantially perpendicular to the rectangular strip (15c) for connection to a first edge of a circuit board (31) and an L-shaped ground plane extension element (14) extending from a second edge (31b) of the circuit board (31) and then turning substantially perpendicular downward to provide a longer ground plane within a confined rectangular space. The antenna (14, 15) is dimensioned so as to be tuned to a resonant frequency in a range from 450 Mhz to 470 Mhz.