Dual-Layer NFC Coil Layout for Larger Sensing Area
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electronic devices face challenges in improving the performance of short-haul communication signals, particularly in enhancing the sensing area and magnetic flux of near field communication (NFC) signals.
Innovation Solution
A communication tag with a circuit board featuring two coils on different conducting layers, where the currents in both coils flow in the same direction, and a chip with opposite polarities, is designed to reduce signal interference and increase the sensing area and magnetic flux by arranging the coils in an intersecting or partially overlapping manner, with a coil feeding circuit that forms 180° reverse differential ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single coil is used for NFC communication, then the device structure is simple, but the sensing area and magnetic flux are limited
Solution Approach 1:
The patent divides the single coil into two separate coils (first coil and second coil) positioned on different conducting layers. Each coil contributes to the overall magnetic flux and sensing area, effectively doubling the functional coverage while maintaining a compact structure through vertical stacking.
Solution Approach 2:
The patent transitions from a single-plane coil configuration to a multi-layer three-dimensional arrangement. By placing coils on different conducting layers (first conducting layer and second conducting layer) and connecting them through vertical vias, the solution expands the sensing volume in the vertical dimension while preserving horizontal footprint.
2Reliability
If coils are placed on different conducting layers, then the sensing performance is improved, but the signal interference from feeding circuits increases
Solution Approach 1:
The patent employs asymmetric current direction design where the first coil and second coil carry currents in opposite directions. This creates opposing magnetic fields that cancel out the interfering magnetic fields generated by the feeding circuits, thereby reducing noise and improving signal-to-noise ratio.
Solution Approach 2:
The patent converts the harmful effect of feeding circuit magnetic fields into a beneficial cancellation mechanism. By strategically positioning and orienting the two coils with opposite current directions, the interference fields from the feeding circuits are neutralized through destructive interference, transforming a source of noise into a filtering mechanism.
3Object-affected harmful factors
If two coils with opposite current directions are used, then the feeding circuit interference is reduced, but the magnetic flux contribution is diminished
Solution Approach 1:
The patent implements a dynamic configuration where the two coils can be independently controlled. During different operational phases, the coils can switch between opposing current directions (for interference cancellation) and same current directions (for magnetic flux enhancement), allowing the system to adapt to different performance requirements.
Solution Approach 2:
The patent employs periodic switching between different current direction configurations. The control circuit alternates between driving the coils in opposite directions (to cancel feeding interference) and in the same direction (to maximize magnetic flux), creating a time-varying magnetic field that maintains both low interference and high flux output.
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 enhances the sensing performance of short-haul communication by increasing the effective sensing area and magnetic flux, allowing for quicker and more reliable pairing with other devices.
Implementation Method 1
a current on the first coil and a current on the second coil have a same direction
Implementation Method 2
the coil feeding circuit may form two 180° reverse differential ports on two sides of the chip, to help reduce signal interference of the feeding circuit to the first coil and the second coil
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
This application provides a communication tag and an electronic device. The communication tag may include a circuit board and a chip disposed on the circuit board. Two coils may be formed on the circuit board. The two coils may be respectively disposed on two different conducting layers of the circuit board. Optionally, the two coils may be disposed in an intersecting manner. In addition, lines for feeding the two coils may be disposed close to each other. The communication tag provided in this application may have a relatively large sensing area, and is capable of radiating a relatively strong magnetic field. This helps improve sensing performance of the communication tag.