Flexible 2D Conveyor Antenna for RF Energy Harvesting Gain
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Solution Overview
Problem
Existing RF-based energy harvesting systems for conveyor belts suffer from low gain and thickness issues, making them unsuitable for thin and flexible industrial conveyor applications, and existing solutions for wireless sensor power supply on conveyor belts result in production interruptions and inefficiencies.
Innovation Solution
A system comprising a thin and flexible 2D energy harvesting antenna integrated into the conveyor belt, combined with a stationary reflector, enhances RF energy harvesting by up to 5 times, using a dielectric material like polyimide or Teflon, and supports wireless sensors with efficient energy accumulation and transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a 3D antenna structure with metal ground plane is used for RF energy harvesting, then energy harvesting efficiency is improved, but the thickness and rigidity increase making it unsuitable for thin flexible conveyor belts
Solution Approach 1:
The patent replaces the traditional 3D metal ground plane with a thin flexible printed circuit board (PCB) containing a meander-shaped ground trace. This ground trace is formed by depositing conductive material (such as silver or copper) onto the flexible PCB substrate, creating a two-dimensional conductive pattern that provides the necessary ground reference while maintaining flexibility and thinness suitable for conveyor belt integration.
Solution Approach 2:
The invention transitions from a three-dimensional antenna structure to a two-dimensional planar design. The radiating element and ground plane are both flattened onto the same flexible PCB substrate, with the meander-shaped ground trace extending in a two-dimensional pattern to provide adequate ground area without adding thickness. This dimensional reduction enables the antenna to be integrated into thin flexible conveyor belts.
2Reliability
If conventional batteries are used to power wireless sensors on conveyor belts, then sensors can operate autonomously, but production interruptions occur when batteries need changing or recharging
Solution Approach 1:
The system enables the conveyor belt sensors to power themselves by harvesting RF energy from the ambient electromagnetic environment. The antenna continuously captures RF signals and the rectifier circuit converts them to electrical energy, which is stored in a capacitor to provide power to the sensor during measurement intervals. This self-powered operation eliminates the need for battery replacement and ensures continuous production without interruptions.
Solution Approach 2:
The invention replaces the mechanical battery system with an electromagnetic energy harvesting system. Instead of using chemical energy storage (batteries) that require physical replacement, the system uses an antenna to capture electromagnetic energy from the environment, converting it to electrical energy through rectification. This substitution eliminates the mechanical intervention of battery changing while maintaining autonomous sensor operation.
3Ease of operation
If RF energy harvesting is implemented without a ground plane, then flexibility and thinness are achieved, but antenna gain and energy harvesting effectiveness decrease
Solution Approach 1:
The ground plane is segmented into a meander-shaped trace pattern on the flexible PCB. This meander configuration allows the ground trace to extend over a larger area while remaining confined to the thin flexible substrate. The segmented meander pattern provides adequate ground area for maintaining antenna gain while preserving the flexibility and thinness required for conveyor belt integration.
Solution Approach 2:
The ground trace is designed with a meander (curved/winding) pattern rather than a straight line. This curved configuration increases the effective ground area within the constraints of the flexible PCB dimensions, improving antenna performance while maintaining the thin flexible form factor suitable for conveyor belt applications.
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 system provides continuous power supply to wireless sensors on moving conveyor belts, improving energy harvesting efficiency and reducing the need for battery changes, thereby minimizing production interruptions and enhancing operational efficiency.
Implementation Method 1
a rectifier circuit for converting the RF energy to electrical energy
Implementation Method 2
a capacitor for storing the electrical energy
Implementation Method 3
The stationary reflector is mounted at a certain distance beneath the non-metallic conveyor belt
Data Source
Figure 1
AI summary
Disclosed herein is a thin 2D movable flexible antenna for energy harvesting and power supply for wireless autonomous sensor nodes or other electronic circuitry integrated into belts of production conveyors. Also disclosed herein is a method of integration of 2D flexible antennas in flat segments of conveyor bands, providing a high gain for the latter, the value of which becomes comparable with the stiff 3D antennas.