2021 Fiscal Year Research-status Report
New metamaterial for efficient and compact WPT system for biological applications
| Project/Area Number |
21K20430
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| Research Institution | Kyushu University |
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Principal Investigator |
BARAKAT ADEL 九州大学, システム情報科学研究院, 助教 (20792039)
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| Project Period (FY) |
2021-08-30 – 2023-03-31
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| Keywords | metamaterial / wireless power transfer / magnetic loss |
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| Outline of Annual Research Achievements |
The main objective of this research is the implementation of a near-field wireless power transfer (WPT) system employing metamaterial inspired geometry. A low magnetic loss near-filed metamaterial was proposed to achieve this objective. A Metamaterial needs to satisfy two conditions to enable field focusing. First, the real part of permeability should be less than 1 (real(μ)<1) in the desired direction for focusing. Second, the imaginary part should be zero (imaginary(μ)=0) to avoid any loss contribution by this metamaterial. Both conditions were realized by proposing multi-ring-resonator (MRR) topology.
Unlike conventional metamaterial, the proposed MRR metamaterial was integrated with the WPT transmitter (TX) to form a meta-TX occupying smaller space. The meta-TX can focus the magnetic flux into a compact WPT receiver (RX), which is embedded inside body tissue. In return, magnetic coupling was improved and WPT efficiency was enhanced.
The proposed design was fabricated and achieved a measured RF-RF WPT efficiency of more than 51% when the RX was mounted inside chicken breast at 9 mm depth. The size of the RX was 50% smaller than the most compact design reported in literature.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
In the initial plan, only testing the performance of the proposed metamaterial based WPT system in air was targeted. Instead, characterization of the system performance was performed also when the receiver is mounted inside chicken breast tissue.
Moreover, the work under this research project has been accepted for publication at the premier IEEE MTT-S international microwave symposium (IMS2022).
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| Strategy for Future Research Activity |
After successful realization of the metamaterial based WPT system in the first year, the current milestone of the research plan is to design and implement an efficient rectifier and integrate it to the RX of the WPT system. Then, the whole integrated system will be tested again. Research results will be reported by the second half of this year.
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| Causes of Carryover |
Due to the COVID pandemic, a planned trip to attend the European microwave week in UK was postponed to April 2022. In addition, for the same reason, a planned CMOS fabrication was rescheduled to the first half of FY2022. So, on-wafer probe purchase was also postponed to the first half of FY2022.
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