NFC Antenna Isolation Using Blocking Devices in Compact Layouts
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Solution Overview
Problem
The challenge of limited space and metal interference in mobile devices leads to poor radiation effects and interference issues with NFC antennas, resulting in reduced signal strength and increased radiation blind regions.
Innovation Solution
An antenna system with an NFC antenna and conventional antennas, utilizing blocking devices such as capacitors, band-pass circuits, and high-pass filters to isolate radio frequency signals, maintaining a gap distance between NFC and conventional antennas, ensuring signal communication within the operating frequency band and preventing leakage to the ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional antennas are placed close to NFC antenna to save space, then space utilization is improved, but radiation effect of NFC antenna deteriorates due to interference and signal leakage to ground
Solution Approach 1:
A blocking device is introduced as an intermediary component between the conventional antenna and ground. This blocking device selectively blocks NFC frequency signals from leaking to ground while allowing conventional antenna frequencies to pass through to ground, thereby resolving the interference problem while maintaining close proximity arrangement for space efficiency
Solution Approach 2:
The blocking device is applied locally at the grounding point of the conventional antenna, creating a frequency-selective barrier only where needed. This localized intervention prevents NFC signal leakage without affecting the overall antenna system design or requiring redesign of the entire antenna structure
2Length of moving object
If NFC antenna size is reduced due to limited assembling space, then device thickness is reduced, but radiation effect deteriorates
Solution Approach 1:
The blocking device acts as a mediator that compensates for the reduced NFC antenna size by preventing signal leakage and interference from nearby conventional antennas, thereby maintaining adequate radiation effect despite the smaller antenna dimensions required for thinner devices
3Reliability
If blocking device is added to prevent signal leakage, then radiation effect is improved, but device complexity increases
Solution Approach 1:
The blocking device is implemented as a localized component at the grounding point rather than requiring system-wide modifications. This localized approach minimizes the increase in device complexity while effectively improving radiation effect by preventing signal leakage only where necessary
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
This solution enhances the radiation effect of NFC antennas by reducing interference, increasing the effective area, and improving the NFC card swiping success rate while maintaining efficient space utilization.
Implementation Method 1
the blocking device is configured to block a radio frequency signal in a frequency band of the NFC antenna
Implementation Method 2
the conventional antenna in another frequency band performs secondary radiation on the NFC frequency band signal
Data Source
AI summary
Embodiments of this application disclose an antenna system and an electronic device. The antenna system includes one NFC antenna and N conventional antennas, and each of the N conventional antennas includes a feed point, a grounding point, and a radiating branch. M conventional antennas in the N conventional antennas include blocking devices. An ith antenna includes an ith radiating branch, an ith feed point, an ith blocking device, and an ith grounding point, the ith radiating branch is coupled to the ith feed point, and the ith radiating branch is coupled to the ith grounding point through the ith blocking device. The blocking device is configured to block a radio frequency signal in a frequency band of the NFC antenna in the M conventional antennas. The M conventional antennas are within a field strength range of radiation of the NFC antenna. Radiation performance of the NFC antenna is improved.