Resonant Inductive Coupling 2026 — PatSnap Eureka
Resonant Inductive Coupling: Patent & Research Intelligence
From series-series topologies achieving 85% efficiency to parity-time symmetric architectures that self-adapt across variable coupling distances — explore the full RIC innovation landscape, sourced from patent and literature records spanning 2010–2023.
What Is Resonant Inductive Coupling?
Resonant inductive coupling (RIC) is a mid-range wireless power transfer technology that exploits magnetic resonance between coupled coils operating at matched frequencies to achieve substantially higher efficiency and transfer distances than conventional inductive coupling. When a transmitter coil and receiver coil are tuned to the same resonant frequency, energy transfer efficiency is dramatically enhanced over a wide range of distances.
The technology is described through several overlapping sub-domains: circuit topology design (series-series, series-parallel, parallel-T, and series-parallel-mixed configurations), coil and resonator architecture (planar spiral resonators, defected ground structure resonators, multi-coil relay arrays, and cavity resonators), compensation and impedance matching, metamaterial enhancement, and novel modalities such as dielectric-loaded cavity resonators and space-time symmetric composite coil architectures.
The field spans publications from at least 2010 to 2023, with particularly dense activity in the 2017–2022 window. Demand is driven by cable-free charging requirements in advanced engineering applications including electric vehicles, medical implants, consumer electronics, and underwater systems. WIPO tracks wireless power transfer as a high-growth technology classification globally.
Assignees are distributed across Asia, Europe, North America, and the Middle East, with a notable concentration of academic literature production in Southeast Asia — Malaysia in particular accounts for at least 5 distinct institutional affiliations publishing on resonant WPT circuit analysis in this dataset.
Innovation Activity & Efficiency Benchmarks
Key quantitative signals from patent and literature records retrieved via PatSnap Eureka, spanning core circuit mechanisms, resonator architectures, and application domains.
RIC Publication Activity by Innovation Period
The 2015–2019 topology diversification window accounts for the densest cluster of records in this dataset, with 2020–2023 reflecting a shift to system integration and novel architectures.
Application Domain Distribution in Dataset
EV charging and medical implants together represent the dominant high-power application drivers, while consumer electronics and underwater systems represent emerging sub-domains.
Four Architecture Clusters in the RIC Landscape
Patent and literature records in this dataset cluster around four distinct technical approaches, each addressing different trade-offs between efficiency, transfer distance, coil size, and application context.
Series/Parallel Resonant Circuit Topologies
The dominant approach involves selecting and optimizing the electrical topology — series-series (SS), series-parallel (SP), or hybrid variants — that connects compensation capacitors to transmitter and receiver coils. IP analytics across this cluster show Shandong University (2017) concluding that SS favors small load resistance while SP favors large load resistance. Universiti Teknologi PETRONAS (2018) reported ~49% efficiency at 20–40 V input using ADS simulation for SS and series-parallel-mixed topologies.
85% efficiency at k = 0.046 — parallel-T (Harbin IT, 2015)Planar Spiral & DGS Resonator Architectures
Planar geometries — including spiral coils and defected ground structure (DGS) resonators — offer compact, printable, and scalable alternatives to wire-wound coils. The Hebrew University of Jerusalem (2011) derived scale-independent coupling terms for planar spirals, fabricating integrated resonators achieving high Q at handheld sizes. The Egypt-Japan University of Science and Technology (2016) demonstrated spiral-strip DGS resonators achieving 78% WPT efficiency at 40 mm with asymmetric TX/RX geometries — showing non-identical coil geometries can still deliver competitive performance.
78% efficiency at 40 mm — DGS asymmetric (EJUST, 2016)Metamaterial-Enhanced & Multi-Relay Architectures
To extend operating range beyond what coil Q factor alone can support, researchers have explored metamaterial lenses (negative-refractive-index materials) inserted between coils, and multi-resonator relay chains that guide power across intermediate stages. The materials science dimension is central here: Kyung Hee University (2010) analyzed metamaterial-inspired loop antennas with two additional coupling rings achieving 93.7% simulated efficiency at 15 cm. The University of Freiburg (2015) proposed an array of multiple equal small-sized resonators forming a relay chain, enabling power delivery to distances exceeding the largest coil radius — directly targeting active implantable medical device (AIMD) powering without batteries.
93.7% simulated efficiency at 15 cm — metamaterial loops (Kyung Hee, 2010)Cavity, Space-Time Symmetric & Dielectric-Loaded Systems
The frontier of the field involves physically unconventional resonator structures departing from planar coil paradigms. The Royal Military College of Canada (2019) proposed dielectric resonator-loaded split cavity achieving 70% efficiency at 7 cm with an electromagnetic-induced transparency-like window. Tongji University (JP patent, 2023) filed on N-th order composite coil systems using parity-time symmetry to maintain pure real eigenfrequencies independent of coupling distance, enabling self-adapting efficiency — a significant departure from conventional frequency-split management. Explore these frontier filings via PatSnap Eureka.
70% efficiency at 7 cm — dielectric cavity (RMC Canada, 2019)Where Resonant Inductive Coupling Is Being Deployed
From high-power EV chassis charging to battery-free medical implants and subsea robotics, RIC is enabling cable-free power delivery across a widening range of contexts.
Electric Vehicle Wireless Charging
EV wireless charging is the highest-power application domain in this dataset. The Industrial Technology Research Institute of Taiwan (2023) designed a passive power receiving unit for EV chassis charging at 50 cm range and 4 MHz switching frequency — demonstrating battery charging to several hundred volts without initial power from the vehicle. Hughes Aircraft Company filed an early EV inductive charging coupler in 1995, representing the historical commercial origin point for this application.
Active Implantable Medical Devices (AIMD)
Resonant inductive coupling is positioned as the enabling technology for battery-free medical implants, where coil miniaturization and efficiency at body-scale distances are critical constraints. The University of Freiburg (2015) explicitly targets AIMD powering without batteries, using resonator relay arrays to reach depth-limited implant positions. Universiti Tenaga Nasional, Malaysia (2018) simulated a 4-coil magnetic resonance system for mid-range WPT in the context of medical and consumer electronics applications. PatSnap's life sciences IP tools cover this domain in depth.
From Foundational Research to Commercial Deployment
Early foundational work (2010–2013): The earliest directly relevant result in this dataset dates to 2010, from Kyung Hee University (Korea), reporting wireless power transmission between metamaterial-inspired loop antennas at 300 MHz with efficiencies of up to 93.7% when supplemented with additional coupling rings — an early demonstration of resonance splitting and multi-ring enhancement. The Hebrew University of Jerusalem (2011) published analysis of planar spiral resonators as a scalable geometry for strongly coupled inductive WPT, establishing geometric and material-independent coupling terms that remain foundational design references.
Mid-stage development and topology diversification (2015–2019): Durham University (2015) published a comprehensive survey and roadmap covering inductive, magnetic resonant, and radiation-based WPT, explicitly mapping the state of the art. The Harbin Institute of Technology (2015) proposed the parallel-T topology for weak-coupling scenarios, achieving 85% efficiency at a coupling coefficient of 0.046. Doshisha University (2019) demonstrated SS capacitive compensation at 10–20 kHz with 80% peak efficiency at 50 mm distance using Litz wire coils. The ITU and IEC have both published standards activity relevant to wireless power transfer in this period.
System-level integration and emerging applications (2020–2023): The most recent filings reflect a shift toward system integration, specific application contexts, and novel physical architectures. Zhejiang University (2021) demonstrated dual-resonant-frequency inductive power transfer for underwater tight-coupling systems. Taiwan's Industrial Technology Research Institute (2023) proposed a passive-element power receiving unit for EV chassis charging at 50 cm range and 4 MHz switching frequency. Tongji University (JP patent, 2023) filed a high-order space-time symmetric wireless energy transmission system using parity-time symmetry principles to maintain optimal efficiency across variable coupling distances.
Key Institutions & Patent Filers in Resonant WPT
The majority of results originate from university research groups, with formal patent activity concentrated among Japanese automotive and industrial corporates. Malaysia accounts for a disproportionate share of academic literature output.
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Five Frontier Signals from 2021–2023 Filings
The most recent patent filings and publications in this dataset reveal five distinct directions that are reshaping the resonant inductive coupling landscape heading into 2026.
Space-Time Symmetric (PT-Symmetric) Resonator Architectures
The Tongji University JP patent (2023) on high-order space-time symmetric wireless energy transmission represents a frontier direction: using PT-symmetry principles, these systems exhibit pure real eigenfrequencies that do not shift with coupling distance, enabling efficiency optimization without real-time frequency tracking. This is a significant departure from conventional frequency-split management. With only one patent result in this dataset covering this approach, IP strategists have a near-term window to file claims before the space fills.
1 patent in dataset — white space opportunityHigh-Power EV Chassis Charging at Extended Range
The 2023 Taiwan ITRI publication on a passive PRU for 50 cm EV chassis charging at 4 MHz pushes the envelope on both power level and gap distance for practical vehicle deployment, using only passive components — no initial power is required from the vehicle battery. Multiple results converge on the 20–50 cm gap as the critical range for practical EV dynamic or static charging. Patent analytics can identify which assignees are closest to commercial claims in this range.
50 cm range — fully passive receiver (ITRI Taiwan, 2023)Underwater Dual-Resonant-Frequency Systems
The dual-channel approach exploiting both fundamental and harmonic energy in seawater environments (Zhejiang University, 2021) is an emerging architectural direction for subsea robotics, sensors, and infrastructure that conventional WPT designs cannot serve. In seawater, electromagnetic attenuation forces tight coupling conditions, making harmonic energy channel exploitation a viable architectural strategy. The IEC has active working groups on underwater power systems standardization.
Dual-channel harmonic exploitation (Zhejiang, 2021)Electromagnetic Shielding as Commercialization Requirement
The Yazaki EP patent (2019) reflects a maturing concern: as resonant WPT systems enter vehicles and consumer products, regulatory compliance requires demonstrated containment of electromagnetic leakage. The patent specifically connects a coaxial cable outer conductor and metal shield to suppress electromagnetic leakage. This signals that shielding and EMI management are becoming first-order design requirements. Component suppliers can build defensible IP positions on shielding and containment architectures independent of coil or topology IP. See PatSnap's trust center for data compliance context.
EM leakage containment — Yazaki EP patent (2019)IP Strategy Signals from the RIC Landscape
Five strategic signals derived directly from the patent and literature records in this dataset, relevant to R&D teams, IP strategists, and technology investors.
Topology Selection Is a Primary IP Differentiation Axis
The SS vs. SP vs. hybrid topology decision directly determines efficiency profiles across load and coupling coefficient ranges. R&D teams should secure claims on topology-specific optimization algorithms and compensation network designs rather than coil geometries alone, which are harder to differentiate.
PT-Symmetric Architectures Are a Defensible White Space
With only one patent result in this dataset covering the parity-time symmetric approach (Tongji University, 2023), and growing academic interest, IP strategists have a near-term window to file claims on PT-symmetric multi-coil resonator systems before the space fills.
EV Charging at 50 cm+ Is an Unsolved Commercialization Problem
Multiple results converge on the 20–50 cm gap as the critical range for practical EV dynamic or static charging. Efficiency at this range with fully passive receiver architectures (as demonstrated by ITRI Taiwan) represents a commercial milestone that is not yet fully claimed in the patent record.
Southeast Asian Institutions Are Potential Collaboration Targets
The volume of Malaysian academic WPT output in this dataset is disproportionate to the region's industrial WPT market. For companies seeking cost-effective co-development partnerships or access to foundational resonant circuit analysis IP, this cluster — including Universiti Teknologi PETRONAS, International Islamic University Malaysia, Universiti Teknologi MARA, and Universiti Tenaga Nasional — warrants outreach.
Resonant Inductive Coupling — key questions answered
Resonant inductive coupling (RIC) is a mid-range wireless power transfer technology that exploits magnetic resonance between coupled coils operating at matched frequencies to achieve substantially higher efficiency and transfer distances than conventional inductive coupling. When a transmitter coil and receiver coil are tuned to the same resonant frequency, energy transfer efficiency is dramatically enhanced over a wide range of distances compared to conventional (non-resonant) inductive coupling.
The dominant approach involves selecting and optimizing the electrical topology — series-series (SS), series-parallel (SP), or hybrid variants — that connects compensation capacitors to transmitter and receiver coils. The choice of topology determines how efficiency scales with load resistance, coupling coefficient, and operating frequency. Shandong University (2017) concluded that SS favors small load resistance while SP favors large load resistance.
Reported efficiencies in this dataset range widely by architecture and distance. Kyung Hee University (2010) achieved 93.7% simulated efficiency at 15 cm using metamaterial-inspired loop antennas with additional coupling rings. The Harbin Institute of Technology (2015) achieved 85% efficiency at a coupling coefficient of 0.046 using the parallel-T topology. Doshisha University (2019) achieved 80% peak efficiency at 50 mm distance using Litz wire coils. Egypt-Japan University of Science and Technology (2016) demonstrated 78% efficiency at 40 mm using DGS resonators.
The field spans electric vehicle (EV) wireless charging, active implantable medical devices (AIMD), underwater systems, consumer electronics and low-power IoT devices, and omnidirectional spatially unconstrained charging. EV wireless charging is the highest-power application domain represented in this dataset.
Based on the most recent filings and publications (2021–2023), emerging directions include: space-time symmetric (parity-time symmetric) resonator architectures (Tongji University, JP 2023); high-power EV chassis charging at 50 cm+ range using fully passive receiver architectures (ITRI Taiwan, 2023); underwater dual-resonant-frequency systems exploiting both fundamental and harmonic energy channels (Zhejiang University, 2021); and electromagnetic shielding and leakage containment as first-order commercialization requirements (Yazaki Corporation EP patent, 2019).
The majority of results originate from university research groups. Among the most active academic assignees are institutions from Malaysia (Universiti Teknologi PETRONAS, International Islamic University Malaysia, Universiti Teknologi MARA, Universiti Tenaga Nasional), China (Zhejiang University, Shandong University, Tongji University, State Grid Jiangxi), Japan (Doshisha University), Korea (Kyung Hee University), and North America (University of Florida, Royal Military College of Canada). Corporate patent filers include Yazaki Corporation (EP, 2019), IHI Corporation (US, 2022), and Tongji University (JP patent, 2023).
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References
- Wireless power transfer via dielectric loaded multi-moded split cavity resonator — Royal Military College of Canada, 2019
- Resonant Configuration Topology Exploration for Inductive Link Power Transfer — International Islamic University Malaysia, 2018
- Advanced Wireless Power Transfer Technologies — Drexel University, 2022
- Wireless Power Transfer Technology Using Resonant Technique — University College of Technology Sarawak, 2019
- Inductive Micro-tunnel for an Efficient Power Transfer — University of Freiburg, 2015
- Wireless Power Transfer: Survey and Roadmap — Durham University, 2015
- Design and Analysis of Resonant Wireless Power Transfer System — Universiti Teknologi PETRONAS, 2018
- Analysis and Compensation of Incomplete Coupling for Omnidirectional Wireless Power Transfer — State Grid Jiangxi Electric Power Co. Ltd, 2019
- Strong coupling optimization with planar spiral resonators — Hebrew University of Jerusalem, 2011
- Resonant enhanced parallel-T topology for weak coupling wireless power transfer pickup applications — Harbin Institute of Technology, 2015
- Asymmetric wireless power transfer systems using coupled DGS resonators — Egypt-Japan University of Science and Technology, 2016
- Wireless Power Transfer Systems Using Metamaterials: A Review — University of Florida, 2020
- Wireless Power Transmission between Two Metamaterial-Inspired Loops at 300 MHz — Kyung Hee University, 2010
- Study on efficiency of different topologies of magnetic coupled resonant wireless charging system — Shandong University, 2017
- Fundamental Investigation of Short-Range Inductive Coupling Wireless Power Transmission by Using Series-Series Capacitive Compensation Topology — Doshisha University, 2019
- Critical Review and Simulation of Mid-range Wireless Power Transfer for Electronic Device — Universiti Tenaga Nasional, 2018
- Dual Resonant Frequency Inductive Power Transfer in an Underwater Tight Coupling System — Zhejiang University, 2021
- Power Receiving Unit for High-Power Resonant Wireless Power Transfer — Industrial Technology Research Institute (ITRI), Taiwan, 2023
- Fundamentals of Inductively Coupled Wireless Power Transfer Systems — 2016
- High-order space-time symmetric wireless energy transmission system and method — Tongji University, JP Patent, 2023 (active)
- Resonance-type non-contact power supply system — Yazaki Corporation, EP Patent, 2019 (active)
- Wireless power transfer device — IHI Corporation, US Design Patent, 2022 (active)
- Analysis of Wireless Power Transfer on the inductive coupling resonant — Universiti Teknologi MARA, 2018
- Design of a single phase series-parallel current injection resonant converter with wireless power transmission — Universiti Teknologi MARA, 2020
- IEEE — Institute of Electrical and Electronics Engineers (wireless power transfer standards and publications)
- IEC — International Electrotechnical Commission (wireless power transfer and underwater systems standards)
- ITU — International Telecommunication Union (wireless power transfer technology classification)
All data and statistics on this page are sourced from the references above and from PatSnap's proprietary innovation intelligence platform. This landscape is derived from a limited set of patent and literature records retrieved across targeted searches and represents a snapshot of innovation signals within this dataset only — it should not be interpreted as a comprehensive view of the full industry.
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