⚡ electrical engineering

A Novel Simultaneous Wireless Power and Information Transfer Strategy Based on Wave Trappers and Partial Power Coils

This paper proposes a novel full-duplex SWPIT strategy utilizing LC wave trappers and partial power coils to physically isolate power and information paths, thereby achieving high-efficiency power transfer alongside simultaneous high-speed bidirectional communication with minimal interference.

Original authors: Qingqing Yuan, Pu Wang, Xunyu Zhou, Kai Xue, Dirui Yang

Published 2026-08-13

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CC BY 4.0

Original authors: Qingqing Yuan, Pu Wang, Xunyu Zhou, Kai Xue, Dirui Yang

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Imagine a world where your phone never needs a charging cable, and your smartwatch talks to your phone without ever pairing up or waiting for a signal. This is the dream of Wireless Power Transfer (WPT), a technology that beams electricity through the air using invisible magnetic fields, much like how a radio station beams music through the air. But here's the tricky part: usually, you can either beam power or beam data, but doing both at the same time on the same track is like trying to drive a race car and send a text message on the same steering wheel without crashing. The signals get jumbled, the power gets weak, and the system gets messy. This is the problem of Simultaneous Wireless Power and Information Transfer (SWPIT). Scientists have been trying to build a "magic highway" where electricity and data can zoom past each other without bumping into one another, but most attempts have been too complicated, too expensive, or only work in one direction at a time.

Now, enter a team of researchers from the Shanghai University of Science and Technology who decided to build a smarter highway. They didn't just try to make the signals play nice; they built a physical separation system using a clever trick involving LC wave trappers (think of them as bouncers at a club who only let specific frequencies in) and partial power coils (coils that are split into sections, like a sandwich with a secret filling). Their big idea was to create a full-duplex system, meaning data can flow in both directions at the exact same time—like a two-way conversation—while power flows through the main channel.

In their study, the team designed a system where the main magnetic coils carry the heavy lifting of electricity, while the "partial" inner coils act as secret tunnels for data. To keep the data from getting drowned out by the massive power signals, they used wave trappers. Imagine these trappers as noise-canceling headphones for the data lines; they are tuned to block the low-frequency power hum while letting the high-frequency data chatter pass through freely. For the data itself, they used a simple and efficient method called ASK modulation, which is like turning a light switch on and off very quickly to send Morse code.

The results of their experiment were quite impressive. They managed to push 54.7 Watts of power (enough to run a bright lightbulb or charge a laptop) while simultaneously sending data in both directions. The "forward" data (from the charger to the device) moved at 200 kbit/s, and the "backward" data (from the device back to the charger) zoomed along at 600 kbit/s. Crucially, they achieved this with very few errors, proving that the "bouncers" (wave trappers) were doing their job perfectly. The system maintained a power transfer efficiency of 82.1%, which is a strong score considering it was doing two jobs at once.

What makes this approach special is that it avoids the complex, expensive electronics that other systems often rely on. Instead of using complicated transformers or high-frequency carriers that are hard to tune, they used simple resonant circuits and the physical layout of the coils to do the heavy lifting. The researchers found that by splitting the coils and using these frequency-selective traps, they could physically isolate the power and data paths, preventing the "crosstalk" that usually ruins these systems.

In short, this paper suggests a new, simpler way to wirelessly charge and talk to devices at the same time. It's not just a theory; they built a working prototype and measured the results. While they didn't claim it's the absolute fastest system ever made, they did show that it balances power, speed, and simplicity better than many existing full-duplex solutions. It's a promising step toward a future where your devices are always charging and always connected, without the mess of tangled wires or confusing signal interference.

Technical Summary: A Novel Simultaneous Wireless Power and Information Transfer Strategy Based on Wave Trappers and Partial Power Coils

Problem Statement
Traditional Simultaneous Wireless Power and Information Transfer (SWPIT) systems face a fundamental challenge in balancing high-efficiency power transfer with high-speed, bidirectional information transmission. Existing solutions generally fall into two categories: dual-path systems, which use multiple coil sets and suffer from increased size and cross-coupling; and shared-coupled-path systems, which use a single magnetic link but often rely on power modulation (limiting data rates and supporting only half-duplex) or carrier injection (which can be complex and limited in stability and range). While recent full-duplex SWPIT systems have improved communication performance, they typically rely on complex duplex structures, high-frequency carriers, or advanced modulation techniques that increase system cost, complexity, and design difficulty. The core problem addressed is the need for a SWPIT architecture that achieves efficient, stable, full-duplex communication without compromising power transfer efficiency or introducing excessive structural complexity.

Methodology
The authors propose a novel full-duplex SWPIT strategy that physically isolates power and information transmission paths using LC wave trappers and a partial power coil structure within an SS (Series-Series) compensation topology.

Topology and Component Roles: The system utilizes a primary and secondary side, each featuring a main outer coil ( $L_{p1}, L_{s1}$ $L_{p 1}, L_{s 1}$ ) and an inner partial coil ( $L_{p2}, L_{s2}$ $L_{p 2}, L_{s 2}$ ).
- Power Path: Power is transmitted via the main coupled coils ( $L_p, L_s$ ) using an SS topology.
- Forward Information Path (Downlink): Information is transmitted from the primary to the secondary side through the main coupled coils. LC wave trappers (a) and (b) are connected in series with the power branch. These are tuned to the forward information carrier frequency ( $f_1$ ) to act as open circuits (blockers) for the power path, confining the information carrier within the coil loop.
- Backward Information Path (Uplink): Information is injected from the secondary to the primary side through the inner partial coils ( $L_{p2}, L_{s2}$ ). This physical separation allows the backward signal to bypass the main power path.
- Interference Suppression: Additional wave trappers (c) and (d) are placed in the forward information detection circuit to block power frequency ( $f_p$ ) and backward information frequency ( $f_2$ ) signals, ensuring clean demodulation. Series capacitors and inductors are added to the wave trappers to ensure zero total impedance at the power frequency, preventing interference with power transfer.
Modulation and Demodulation: The system employs Amplitude Shift Keying (ASK) modulation for information transmission. This choice simplifies the modulation and demodulation processes while maintaining high performance.
Theoretical Analysis: The paper derives equivalent circuit models for power transmission, forward information, and backward information paths. It analyzes crosstalk mechanisms, demonstrating that the frequency separation ( $f_2 > f_1 \gg f_p$ ) and the high impedance of wave trappers at non-resonant frequencies effectively isolate the paths. The analysis confirms that the backward information branch acts as an open circuit during power transmission, minimizing power loss.

Key Contributions

Physical Isolation Strategy: The introduction of a partial-coil structure combined with LC wave trappers to physically separate power, forward information, and backward information paths, significantly reducing mutual interference without complex active duplexing hardware.
Full-Duplex Capability: The system achieves simultaneous bidirectional communication (downlink and uplink) while transmitting power, overcoming the half-duplex limitations of many existing shared-path SWPIT systems.
Simplified Architecture: By utilizing ASK modulation and passive LC filtering (wave trappers) instead of complex active duplexers or high-frequency carrier injection schemes, the system reduces component count, cost, and design complexity.
Comprehensive Crosstalk Analysis: The paper provides a detailed mathematical derivation of interference gains and Signal-to-Noise Ratios (SNR), validating that the proposed topology minimizes power-to-information and information-to-information crosstalk.

Experimental Results
The proposed system was validated through simulation and experimental prototyping with the following parameters:

Power Transfer: Operating at 100 kHz with a 30 V DC input, the system delivered 54.7 W of output power to a 20 Ω load.
Efficiency: The system achieved a transmission efficiency of 82.1% under full-duplex communication conditions.
Data Rates:
- Forward (Downlink): Achieved a stable transmission rate of 200 kbit/s.
- Backward (Uplink): Achieved a stable transmission rate of 600 kbit/s.
Performance: Experimental waveforms confirmed low bit error rates and successful demodulation. The interference voltage caused by power transfer on the information lines was found to be negligible after bandpass filtering. The system maintained stable operation even as the communication rate increased, provided each bit contained at least five carrier peaks for reliable envelope detection.

Significance and Claims
The paper claims that the proposed strategy offers a superior balance between power transfer efficiency, data transmission rates, and system complexity compared to existing SWPIT solutions.

Integration and Scalability: The use of passive wave trappers and partial coils allows for a more compact and integrable design compared to dual-path systems.
Cost-Effectiveness: The reliance on ASK modulation and standard LC components reduces implementation costs relative to systems requiring complex active circuitry.
Performance Balance: While acknowledging that some existing works may achieve slightly higher peak efficiencies or data rates in isolation, the authors assert that their system achieves the highest experimentally verified data rates among compared full-duplex SWPIT systems while retaining competitive power transfer efficiency (82.1%).
Practical Application: The authors position this work as a promising solution for wireless power transfer to intelligent terminals where simultaneous, efficient, and bidirectional communication is required without the burden of complex system architectures.

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