Stacked Rectenna Module for Low-Loss RF-to-DC Conversion
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Solution Overview
Problem
Existing energy harvesting devices are inefficient due to low rectification efficiency, limited frequency operation, and scalability issues, leading to limited battery life and power delivery in wireless electronics.
Innovation Solution
An energy harvesting module with a stacked arrangement of an antenna and rectifier circuit, minimizing interconnect losses and using an integrated rectifier circuit without strip line or solder-mount components, allowing for efficient RF to DC conversion and modular design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional printed circuit board with discrete rectifier components is used, then the device structure is simple to manufacture, but the rectification efficiency is low and the form factor is large
Solution Approach 1:
The patent merges the antenna and rectifier circuit into a single integrated structure called a rectenna, where the rectifier components are directly fabricated on the antenna substrate. This integration eliminates the need for separate discrete components and interconnectors, thereby reducing energy losses while maintaining manufacturability through conventional PCB fabrication processes.
Solution Approach 2:
The patent transitions from a planar arrangement of discrete components to a three-dimensional integrated structure where the rectifier circuit is embedded within or adjacent to the antenna elements. This dimensional change allows for shorter current paths and reduced parasitic effects, improving rectification efficiency without significantly increasing the overall form factor.
2Loss of energy
If discrete rectifier components with interconnectors are used, then the device is easy to manufacture, but interconnect losses increase and efficiency decreases
Solution Approach 1:
The rectifier components are directly fabricated on the antenna substrate using the same PCB processes, eliminating the need for separate interconnectors. This merging of functions reduces the number of connection points and interconnect paths, thereby minimizing interconnect losses while maintaining ease of manufacture through standard fabrication techniques.
3Adaptability or versatility
If conventional rectifier designs are used, then the structure is simple, but the frequency operation range is limited and scalability is poor
Solution Approach 1:
The integrated rectenna design incorporates adjustable matching networks and configurable rectifier topologies that can be adapted to operate across multiple frequency bands. The modular structure allows different antenna elements and rectifier configurations to be combined, enabling the same basic design to serve multiple frequency ranges from sub-6 GHz to mmWave bands.
Solution Approach 2:
The rectenna is designed as a modular array of identical or similar unit cells, each capable of independent operation. This segmentation allows the system to be scaled by simply adding or removing unit cells, and enables frequency tuning by adjusting the configuration of individual modules without redesigning the entire structure.
4Loss of energy
If far-field rectennas are used for wireless power transmission, then wireless charging is enabled, but rectification efficiency remains low
Solution Approach 1:
The patent optimizes the rectifier circuit parameters including transistor sizing, biasing conditions, and impedance matching networks to maximize power conversion efficiency across different input power levels. By adjusting these parameters, the rectenna maintains high efficiency even when operating in the far-field where received power levels vary, thereby improving both rectification efficiency and power delivery capability.
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 solution achieves improved efficiency, reduced form factor, and scalability, enabling wireless charging of devices with increased power delivery and modularity, particularly effective in high-frequency bands like 5G NR FR2.
Implementation Method 1
An antenna (1) has a planar radiator and is configured to receive incoming electromagnetic (EM) radiation and generate an alternating current (AC) antenna signal
Implementation Method 2
The rectifier circuit (3) is arranged in a plane parallel to and adjacent to the planar radiator and configured to rectify the AC antenna signal and generate a direct current (DC) battery charging signal
Data Source
AI summary
Disclosed herein is an energy harvesting module, including an antenna having a planar radiator and configured to receive incoming electromagnetic radiation and generate an AC antenna signal; a rectifier circuit arranged in a plane parallel to and adjacent to the planar radiator and configured to rectify the AC antenna signal and generate a DC battery charging signal; and a battery configured to receive the DC battery charging signal.