New breakthrough in miniaturized antennas promises enhanced performance for wireless communication in challenging environments

A research team led by Professor Huizhu Hu from the Zhejiang University and Zhejiang Lab has developed a groundbreaking low-frequency receiving antenna using optically levitated nanoparticles, achieving a near 10,0000-fold reduction in size compared to conventional solutions. Published in PhotoniX on January 29, 2025, this innovation aims to address long-standing challenges in miniaturizing antennas for critical low-frequency (LF) communication scenarios such as underwater exploration, underground sensing, and ionospheric waveguides.

Why It Matters

Low-frequency wireless signals (30–300 kHz) excel in long-range transmission, penetration through obstacles, and anti-interference capabilities. However, traditional antennas face a fundamental trade-off: smaller size severely compromises sensitivity. Existing solutions, like magnetoelectric coupling antennas, are limited to centimeter-scale dimensions due to their reliance on resonant frequency inversely proportional to antenna size.

How It Works

The team’s nano-antenna leverages laser-trapped silica nanoparticles (143 nm diameter) levitated in a high vacuum. Key advancements include:

1. Charge Enhancement: Using focused electron beams, nanoparticles stably carry over 200 net charges—boosting electric field sensitivity.
2. Size-Frequency Decoupling: The nanoparticles’ resonant frequency depends on laser trapping parameters (e.g., optical power) rather than physical dimensions, enabling 100 nm size antennas to operate across 30 kHz–180 kHz.
3. High-Fidelity Signal Demodulation: With binary frequency-shift keying (2FSK) modulation, the system achieved a <0.1% bit error rate at 0.5 kbit/s under weak fields (0.1 V/m), validated in a vacuum of 2×10⁻⁷ mbar.

Technical Highlights

1. Tunability: Optical trap power adjustment allows continuous frequency tuning, achieving sensitivity better than 10 μV/cm/√Hz.
2. Vector Detection: 3D motion tracking enables omnidirectional signal reception, outperforming scalar-based traditional antennas.
3. Real-World Validation: Successful image transmission with controlled error rates demonstrated practical viability.

Current Limitations & Future Prospects

While the nano-antenna’s sensitivity remains 3–4 orders lower than conventional designs, its nanoscale size and tunability offer unique advantages in extreme environments (e.g., deep-sea or confined spaces). Future work will focus on:

1. Array Integration: Expanding bandwidth via multi-particle coordination.
2. Frequency Extension: Adapting the platform to even lower frequencies using magnetic levitation or optimized materials.
3. Chip-Scale Deployment: Merging vacuum trapping systems with semiconductor fabrication for portable devices.

Expert Perspective

“This fascinating paper considers the use of a levitated nanoparticle as a compact antenna for signals communicated as an electric field.” commented a PhotoniX reviewer.

Learn More
Full paper: Optically levitated nanoparticles as receiving antennas for low frequency wireless communication
Journal: PhotoniX

Expert Contact
Zhenhai Fu
Zhejiang Lab
fuzhenhai@zju.edu.cn

Original Publication
Zhenhai Fu, Jinsheng Xu, Shaochong Zhu, Chaoxiong He, Xunming Zhu, Xiaowen Gao, Han Cai, Peitong He, Zhiming Chen, Yizhou Zhang, Nan Li, Xingfan Chen, Ying Dong, Shiyao Zhu, Cheng Liu & Huizhu Hu
Journal: PhotoniX
Method of Research: News article
Article Title: Optically levitated nanoparticles as receiving antennas for low frequency wireless communication
Article Publication Date: 29-Jan-2025
DOI: 10.1186/s43074-025-00159-6

Media Contact
Liwei Zhu
Chinese Society for Optical Engineering
zhuliwei@csoe.org.cn

Source: EurekAlert!