Hemodialysis is achieved by implanting a smart arteriovenous graft (AVG) to build a vascular pathway, but reliability and stability in data transmission cannot be guaranteed. To address this issue, a miniaturized dual-band circularly polarized implantable antenna operating at 1.4 GHz (for energy transmission) and 2.45 GHz (for wireless telemetry), implanted in a wireless arteriovenous graft monitoring device (WAGMD), has been designed. The antenna design incorporates a rectangular serpentine structure on the radiation surface to reduce its volume to 9.144 mm. Furthermore, matching rectangular slots on the radiation surface and the ground plane enhance the antenna's circular polarization performance. The simulated effective 3 dB axial ratio (AR) bandwidths are 11.43% (1.4 GHz) and 12.65% (2.45 GHz). The simulated peak gains of the antenna are -19.55 dBi and -22.85 dBi at 1.4 GHz and 2.45 GHz, respectively. The designed antenna is implanted in a WAGMD both in the simulation and the experiment. The performance of the system is simulated in homogeneous human tissue models of skin, fat, and muscle layers, as well as a realistic adult male forearm model. The measurement results in a minced pork environment align closely with the simulation results.
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http://dx.doi.org/10.3390/s24144743 | DOI Listing |
Interactions (Cham)
March 2024
Institute of Physics, The University of Tokyo, Komaba, Meguro-ku, 153-8902 Tokyo Japan.
We have developed a microwave spectrometer for a measurement of the Lamb shift of antihydrogen atoms towards the determination of the antiproton charge radius. The spectrometer consists of two consecutive apparatuses, of which the first apparatus, (HFS), filters out hyperfine states and pre-selects the state, and the second apparatus, (MWS), sweeps the frequency around the target transition to obtain the spectrum. We optimized the geometry of the apparatuses by evaluating the S-parameter that represents the ratio of the reflected microwave signal over the input, utilizing microwave simulations based on the finite element method.
View Article and Find Full Text PDFSci Rep
October 2024
Department of Electronic Engineering, Hanyang University, Seoul, 04763, South Korea.
Nanomicro Lett
July 2024
Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Academy for Engineering & Technology, Fudan University, Shanghai, 200438, People's Republic of China.
Broadband electromagnetic (EM) wave absorption materials play an important role in military stealth and health protection. Herein, metal-organic frameworks (MOFs)-derived magnetic-carbon CoNiM@C (M = Cu, Zn, Fe, Mn) microspheres are fabricated, which exhibit flower-like nano-microstructure with tunable EM response capacity. Based on the MOFs-derived CoNi@C microsphere, the adjacent third element is introduced into magnetic CoNi alloy to enhance EM wave absorption performance.
View Article and Find Full Text PDFPLoS One
April 2024
Department of Electrical Engineering, College of Engineering, Qassim University, Unaizah, Saudi Arabia.
To satisfy the requirements of modern communication systems and wearables using 2.4/5.8 GHz band this paper presents a simple, compact, and dual-band solution.
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