Pub Date : 2024-04-01DOI: 10.1109/JERM.2024.3378573
A. De Cillis;C. Merla;G. Monti;L. Tarricone;M. Zappatore
The adoption of high-frequency irreversible electroporation in various medical treatments is becoming increasingly prevalent. There is currently a special focus on its applications in oncology, offering new perspectives in terms of treatable tumor types and treatment effectiveness. A multitude of parameters can influence the efficiency and effectiveness of high-frequency irreversible electroporation procedures, with the selection of suitable electrodes and possible prediction of ablated area as interesting examples. In this paper, we demonstrate that machine-learning strategies, specifically neural networks, provide an appropriate approach for optimizing the choice of some electrode characteristics, and predicting the ablation area, this being quite useful in high-frequency electroporation applications in oncology. This possibility, in turn, may lead to superior results in high-frequency irreversible electroporation, and to a significant reduction of the time required for achieving them.
{"title":"High-Frequency Irreversible Electroporation: Optimum Parameter Prediction via Machine-Learning","authors":"A. De Cillis;C. Merla;G. Monti;L. Tarricone;M. Zappatore","doi":"10.1109/JERM.2024.3378573","DOIUrl":"https://doi.org/10.1109/JERM.2024.3378573","url":null,"abstract":"The adoption of high-frequency irreversible electroporation in various medical treatments is becoming increasingly prevalent. There is currently a special focus on its applications in oncology, offering new perspectives in terms of treatable tumor types and treatment effectiveness. A multitude of parameters can influence the efficiency and effectiveness of high-frequency irreversible electroporation procedures, with the selection of suitable electrodes and possible prediction of ablated area as interesting examples. In this paper, we demonstrate that machine-learning strategies, specifically neural networks, provide an appropriate approach for optimizing the choice of some electrode characteristics, and predicting the ablation area, this being quite useful in high-frequency electroporation applications in oncology. This possibility, in turn, may lead to superior results in high-frequency irreversible electroporation, and to a significant reduction of the time required for achieving them.","PeriodicalId":29955,"journal":{"name":"IEEE Journal of Electromagnetics RF and Microwaves in Medicine and Biology","volume":"8 3","pages":"220-228"},"PeriodicalIF":3.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142041434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.1109/JERM.2024.3381333
Chen Xue;Guanglei Zhou;Alex M. H. Wong
A novel electromagnetic excitation method – the Huygens’ cylinder – is proposed to improve the B 1+ field homogeneity of the high-field (HF) and ultra-high field (UHF) magnetic resonance imaging (MRI). Based on the concept of the Huygens’ box, we calculate the currents on a cylindrical boundary that can synthesize an arbitrary electromagnetic wave inside the enclosed region. Specifically, we excite a right-handed circularly polarized (B 1+ ) travelling wave with high mode purity inside the Huygens’ cylinder coil. The simulated B 1+ field obtained from several 3T and 7T MR scenarios are reported and compared with birdcage coils. In the unloaded scenarios, the Huygens’ cylinder achieves superior B 1+ -field homogeneity over both the sagittal and axial plane compared to the birdcage coil for both 3T and 7T MRI. In the loaded scenarios, the Huygens’ cylinder achieves superior B 1+ -field homogeneity over the sagittal plane and comparable B 1+ -field homogeneity over the axial plane for both 3T and 7T MRI compared to the birdcage coil. Moreover, the 7T Huygens’ cylinder can generate a uniform field over a much larger region, enabling the imaging of a large part of the human body. The Huygens’ cylinder greatly improves the homogeneity of B 1+ field and is free from the dielectric resonance limitation suffered by conventional RF coils. It has strong potential as future RF coils in HF and UHF MR systems.
{"title":"Metasurface Approach to Generate Homogeneous B1+ Field for High-Field and Ultra-High-Field MRI","authors":"Chen Xue;Guanglei Zhou;Alex M. H. Wong","doi":"10.1109/JERM.2024.3381333","DOIUrl":"https://doi.org/10.1109/JERM.2024.3381333","url":null,"abstract":"A novel electromagnetic excitation method – the Huygens’ cylinder – is proposed to improve the B\u0000<sub>1</sub>\u0000<sup>+</sup>\u0000 field homogeneity of the high-field (HF) and ultra-high field (UHF) magnetic resonance imaging (MRI). Based on the concept of the Huygens’ box, we calculate the currents on a cylindrical boundary that can synthesize an arbitrary electromagnetic wave inside the enclosed region. Specifically, we excite a right-handed circularly polarized (B\u0000<sub>1</sub>\u0000<sup>+</sup>\u0000) travelling wave with high mode purity inside the Huygens’ cylinder coil. The simulated B\u0000<sub>1</sub>\u0000<sup>+</sup>\u0000 field obtained from several 3T and 7T MR scenarios are reported and compared with birdcage coils. In the unloaded scenarios, the Huygens’ cylinder achieves superior B\u0000<sub>1</sub>\u0000<sup>+</sup>\u0000-field homogeneity over both the sagittal and axial plane compared to the birdcage coil for both 3T and 7T MRI. In the loaded scenarios, the Huygens’ cylinder achieves superior B\u0000<sub>1</sub>\u0000<sup>+</sup>\u0000-field homogeneity over the sagittal plane and comparable B\u0000<sub>1</sub>\u0000<sup>+</sup>\u0000-field homogeneity over the axial plane for both 3T and 7T MRI compared to the birdcage coil. Moreover, the 7T Huygens’ cylinder can generate a uniform field over a much larger region, enabling the imaging of a large part of the human body. The Huygens’ cylinder greatly improves the homogeneity of B\u0000<sub>1</sub>\u0000<sup>+</sup>\u0000 field and is free from the dielectric resonance limitation suffered by conventional RF coils. It has strong potential as future RF coils in HF and UHF MR systems.","PeriodicalId":29955,"journal":{"name":"IEEE Journal of Electromagnetics RF and Microwaves in Medicine and Biology","volume":"8 2","pages":"155-162"},"PeriodicalIF":3.2,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141084778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-31DOI: 10.1109/JERM.2024.3405185
Sakthi Abirami Balakrishnan;Esther Florence Sundarsingh;Vimal Samsingh Ramalingam;Aishwarya N
The correlation> between driving posture and overall health is paramount, underscoring the necessity of maintaining proper seating positions for individuals. Prolonged periods of incorrect posture significantly contribute to the prevalence of musculoskeletal disorders among sedentary workers. The proposed research presents a novel approach utilizing a conformal and cost-effective body-coupled microwave sensor for monitoring driving positions and enhancing thermal comfort in the automotive sector. Integrated into the backrest of the vehicle seat, the sensor employs microwave-sensing elements to detect various driving postures based on shifts in resonant frequency. Through trials involving 12 participants, including 10 drivers adopting four distinct driving postures, and validation with machine learning classifiers, the effectiveness and reliability of the prototype are demonstrated. Subsequent integration with a Peltier cooling system and dashboard display further enhances occupant thermal comfort by accurately recognizing driving postures, providing corrective messages, and automatically activating the cooling system as needed.
{"title":"Conformal Microwave Sensor for Enhanced Driving Posture Monitoring and Thermal Comfort in Automotive Sector","authors":"Sakthi Abirami Balakrishnan;Esther Florence Sundarsingh;Vimal Samsingh Ramalingam;Aishwarya N","doi":"10.1109/JERM.2024.3405185","DOIUrl":"https://doi.org/10.1109/JERM.2024.3405185","url":null,"abstract":"The correlation> between driving posture and overall health is paramount, underscoring the necessity of maintaining proper seating positions for individuals. Prolonged periods of incorrect posture significantly contribute to the prevalence of musculoskeletal disorders among sedentary workers. The proposed research presents a novel approach utilizing a conformal and cost-effective body-coupled microwave sensor for monitoring driving positions and enhancing thermal comfort in the automotive sector. Integrated into the backrest of the vehicle seat, the sensor employs microwave-sensing elements to detect various driving postures based on shifts in resonant frequency. Through trials involving 12 participants, including 10 drivers adopting four distinct driving postures, and validation with machine learning classifiers, the effectiveness and reliability of the prototype are demonstrated. Subsequent integration with a Peltier cooling system and dashboard display further enhances occupant thermal comfort by accurately recognizing driving postures, providing corrective messages, and automatically activating the cooling system as needed.","PeriodicalId":29955,"journal":{"name":"IEEE Journal of Electromagnetics RF and Microwaves in Medicine and Biology","volume":"8 4","pages":"355-362"},"PeriodicalIF":3.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-30DOI: 10.1109/JERM.2024.3402048
Fei Xue;Lei Guo;Alina Bialkowski;Amin M. Abbosh
Quantitative medical microwave imaging based on deep learning (DL) faces the overfitting problem due to limited training samples available in the clinic database. In this article, a U-Net-like DL model that can reconstruct the dielectric properties of brain tissue using time-domain signals is presented. A transfer learning approach is employed to alleviate the overfitting problem caused by limited training samples. In the proposed approach, the model is first trained with a dataset of random objects in a defined imaging domain and the corresponding time-domain signals. Subsequently, the pre-trained model is fine-tuned using simulation data from an unhealthy object. The final trained model can accurately reconstruct various tissues and abnormal lesions in an unhealthy object and avoid erroneous reconstruction of unexpected lesions in a healthy image of the object. The method is tested using a 16-antenna head imaging system operating across the band 0.5-2 GHz. The results confirm the superior performance of the method, in imaging both healthy and unhealthy brains, as measured using the root mean squared error, the correlation coefficient, the structural similarity index measure, and the peak signal-to-noise ratio. The presented method is a potential solution to mitigate the problem of erroneously predicting lesions in healthy tissues.
{"title":"Transfer Deep Learning for Dielectric Profile Reconstruction in Microwave Medical Imaging","authors":"Fei Xue;Lei Guo;Alina Bialkowski;Amin M. Abbosh","doi":"10.1109/JERM.2024.3402048","DOIUrl":"https://doi.org/10.1109/JERM.2024.3402048","url":null,"abstract":"Quantitative medical microwave imaging based on deep learning (DL) faces the overfitting problem due to limited training samples available in the clinic database. In this article, a U-Net-like DL model that can reconstruct the dielectric properties of brain tissue using time-domain signals is presented. A transfer learning approach is employed to alleviate the overfitting problem caused by limited training samples. In the proposed approach, the model is first trained with a dataset of random objects in a defined imaging domain and the corresponding time-domain signals. Subsequently, the pre-trained model is fine-tuned using simulation data from an unhealthy object. The final trained model can accurately reconstruct various tissues and abnormal lesions in an unhealthy object and avoid erroneous reconstruction of unexpected lesions in a healthy image of the object. The method is tested using a 16-antenna head imaging system operating across the band 0.5-2 GHz. The results confirm the superior performance of the method, in imaging both healthy and unhealthy brains, as measured using the root mean squared error, the correlation coefficient, the structural similarity index measure, and the peak signal-to-noise ratio. The presented method is a potential solution to mitigate the problem of erroneously predicting lesions in healthy tissues.","PeriodicalId":29955,"journal":{"name":"IEEE Journal of Electromagnetics RF and Microwaves in Medicine and Biology","volume":"8 4","pages":"344-354"},"PeriodicalIF":3.0,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-29DOI: 10.1109/JERM.2024.3379747
Jordan Krenkevich;Gabrielle Fontaine;Evelyne Hluszok;Tyson Reimer;Stephen Pistorius
Breast phantoms are required to test and evaluate microwave breast imaging systems before clinical applications. Shell-based breast phantoms are versatile, reproducible, low-cost, stable, and capable of mimicking the morphology and dielectric properties of the breast. In past work, 3D-printable plastics have been used to fabricate the shells in these phantoms, but the low permittivity plastics limit the dielectric accuracy of the phantoms. Furthermore, the liquids in these shell-based phantoms are prone to air bubbles, which may introduce undesirable microwave scattering. This work examines new tissue-mimicking materials to address these challenges. Low-permittivity 3D-printed plastic filament was replaced with a graphite, carbon-black, and resin mixture to mimic skin properties within the 0.4–9.0 GHz range. Glycerin and Triton X-100 were replaced by diethylene glycol butyl ether (DGBE) solutions to mimic the properties of adipose and fibroglandular tissue. The resin-based material more closely modelled the properties of ex vivo tissue samples than 3D-printed plastics. The DGBE solutions had improved dielectric properties compared to the glycerin and Triton X-100 solutions. The DGBE solutions are advantageous compared to glycerin and Triton X-100 solutions due to their lower viscosity, decreased susceptibility to air bubble formation, improved short-term stability, temperature stability, and enhanced long-term stability, facilitating the reusability of these materials. The materials investigated in this work can be used to produce more dielectrically accurate breast phantoms with improved stability and experimental utility for microwave breast imaging.
{"title":"Tissue Mimicking Materials for Shell-Based Phantoms in Breast Microwave Sensing","authors":"Jordan Krenkevich;Gabrielle Fontaine;Evelyne Hluszok;Tyson Reimer;Stephen Pistorius","doi":"10.1109/JERM.2024.3379747","DOIUrl":"https://doi.org/10.1109/JERM.2024.3379747","url":null,"abstract":"Breast phantoms are required to test and evaluate microwave breast imaging systems before clinical applications. Shell-based breast phantoms are versatile, reproducible, low-cost, stable, and capable of mimicking the morphology and dielectric properties of the breast. In past work, 3D-printable plastics have been used to fabricate the shells in these phantoms, but the low permittivity plastics limit the dielectric accuracy of the phantoms. Furthermore, the liquids in these shell-based phantoms are prone to air bubbles, which may introduce undesirable microwave scattering. This work examines new tissue-mimicking materials to address these challenges. Low-permittivity 3D-printed plastic filament was replaced with a graphite, carbon-black, and resin mixture to mimic skin properties within the 0.4–9.0 GHz range. Glycerin and Triton X-100 were replaced by diethylene glycol butyl ether (DGBE) solutions to mimic the properties of adipose and fibroglandular tissue. The resin-based material more closely modelled the properties of ex vivo tissue samples than 3D-printed plastics. The DGBE solutions had improved dielectric properties compared to the glycerin and Triton X-100 solutions. The DGBE solutions are advantageous compared to glycerin and Triton X-100 solutions due to their lower viscosity, decreased susceptibility to air bubble formation, improved short-term stability, temperature stability, and enhanced long-term stability, facilitating the reusability of these materials. The materials investigated in this work can be used to produce more dielectrically accurate breast phantoms with improved stability and experimental utility for microwave breast imaging.","PeriodicalId":29955,"journal":{"name":"IEEE Journal of Electromagnetics RF and Microwaves in Medicine and Biology","volume":"8 3","pages":"213-219"},"PeriodicalIF":3.0,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142041385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-28DOI: 10.1109/JERM.2024.3402985
Prakrati Azad;Ankita Kumari;M. Jaleel Akhtar
Blood cholesterol and triglycerides are vital indicators of heart functioning, as their abnormal values can cause atherosclerosis resulting into conditions like hypertension, cerebrovascular accident, etc. Conventional enzyme-based spectroscopy employed in pathological laboratories necessitate complicated steps involving several extra-pure reagents, expensive instruments, and highly skilled professionals. In this work, a novel RF biosensor with high quality factor (Q) and improved sensitivity is proposed for detection of various solutes such as glucose, electrolytes, lipid profile etc., in human blood. The proposed RF sensor is based on the substrate integrated waveguide (SIW) technology to acquire an enhanced Q of 390. The sensitivity of the proposed biosensor for estimation of Triglycerides mixture (TM) in blood serum is substantially enhanced using the Lipase enzyme as a bioreceptor. Various parameters of the proposed RF SIW sensor structure are optimized using the CST-MWS software, and the designed sensor is fabricated on 1.6 mm thick Taconic (TLY-5) substrate using the photolithography technique. The fabricated RF biosensor is tested using the network analyzer to monitor the transmission coefficient in the S-band frequency range, which provides an enhanced sensitivity of 0.554 MHz/mg.dL −1 for triglyceride levels in blood serum. The proposed RF biosensor with Lipase as a bioreceptor is able to detect the triglyceride concentrations of 150 mg/dL and 200 mg/dL (i.e., healthy, and border-line triglyceride limits) in blood serum, which makes it ideally suited for estimation of various solutes in the blood plasma.
{"title":"Lipase Assisted Improved RF Biosensor for Triglycerides Level Detection in Blood Serum","authors":"Prakrati Azad;Ankita Kumari;M. Jaleel Akhtar","doi":"10.1109/JERM.2024.3402985","DOIUrl":"https://doi.org/10.1109/JERM.2024.3402985","url":null,"abstract":"Blood cholesterol and triglycerides are vital indicators of heart functioning, as their abnormal values can cause atherosclerosis resulting into conditions like hypertension, cerebrovascular accident, etc. Conventional enzyme-based spectroscopy employed in pathological laboratories necessitate complicated steps involving several extra-pure reagents, expensive instruments, and highly skilled professionals. In this work, a novel RF biosensor with high quality factor (Q) and improved sensitivity is proposed for detection of various solutes such as glucose, electrolytes, lipid profile etc., in human blood. The proposed RF sensor is based on the substrate integrated waveguide (SIW) technology to acquire an enhanced Q of 390. The sensitivity of the proposed biosensor for estimation of Triglycerides mixture (TM) in blood serum is substantially enhanced using the Lipase enzyme as a bioreceptor. Various parameters of the proposed RF SIW sensor structure are optimized using the CST-MWS software, and the designed sensor is fabricated on 1.6 mm thick Taconic (TLY-5) substrate using the photolithography technique. The fabricated RF biosensor is tested using the network analyzer to monitor the transmission coefficient in the S-band frequency range, which provides an enhanced sensitivity of 0.554 MHz/mg.dL\u0000<sup>−1</sup>\u0000 for triglyceride levels in blood serum. The proposed RF biosensor with Lipase as a bioreceptor is able to detect the triglyceride concentrations of 150 mg/dL and 200 mg/dL (i.e., healthy, and border-line triglyceride limits) in blood serum, which makes it ideally suited for estimation of various solutes in the blood plasma.","PeriodicalId":29955,"journal":{"name":"IEEE Journal of Electromagnetics RF and Microwaves in Medicine and Biology","volume":"8 3","pages":"265-272"},"PeriodicalIF":3.0,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142041387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-28DOI: 10.1109/JERM.2024.3401572
Hailian Liu;Jingjing Shi;Le Song;Lijia Liu;Yukang Wang;Tonglei Cheng;Jianqing Wang
In this work, a novel miniaturized multi-resonant conformal antenna system has been proposed for wireless electronic capsule applications. It consists of a swallowable in-body antenna and two kinds of spiral/meandering on-body antennas with a simple structure and a low profile. The in-body transmitting antenna has a hollow cylinder-like structure with a size of $pi times 8^{2} times$ 26 mm $^{3}$ , which is a combination of a helical spiral conformed on a flexible substrate and a planar spiral on a high dielectric substrate, to generate multi-resonant frequencies. It operates in three bands, Medical Implanted Communication Service (MICS) band (402 $-$ 405 MHz), Wireless Medical Telemetry Service (WMTS) band (1427 $-$ 1432 MHz), and the Industrial, Scientific, and Medical (ISM) band (2.4 $-$ 2.4835 GHz). The on-body receiving antennas have a planar spiral structure with a size of 20 × 6.8 × 27 mm $^{3}$ and a planar meandered structure with a size of 42 × 10 × 1.6 mm $^{3}$ , respectively, which are suitable for wearable terminals. The performance of the proposed antenna system is analyzed and validated using a muscle-equivalent model, a multi-layer tissue model, a numerical human model in simulations, and a liquid phantom in experiments. Simulation and experimental results show the good potential of the antenna system for intra-body communication scenarios such as wireless electronic capsules.
{"title":"Novel Multiband Antenna Design and Performance Evaluation for Wireless Electronic Capsule Systems","authors":"Hailian Liu;Jingjing Shi;Le Song;Lijia Liu;Yukang Wang;Tonglei Cheng;Jianqing Wang","doi":"10.1109/JERM.2024.3401572","DOIUrl":"https://doi.org/10.1109/JERM.2024.3401572","url":null,"abstract":"In this work, a novel miniaturized multi-resonant conformal antenna system has been proposed for wireless electronic capsule applications. It consists of a swallowable in-body antenna and two kinds of spiral/meandering on-body antennas with a simple structure and a low profile. The in-body transmitting antenna has a hollow cylinder-like structure with a size of \u0000<inline-formula><tex-math>$pi times 8^{2} times$</tex-math></inline-formula>\u0000 26 mm\u0000<inline-formula><tex-math>$^{3}$</tex-math></inline-formula>\u0000, which is a combination of a helical spiral conformed on a flexible substrate and a planar spiral on a high dielectric substrate, to generate multi-resonant frequencies. It operates in three bands, Medical Implanted Communication Service (MICS) band (402\u0000<inline-formula><tex-math>$-$</tex-math></inline-formula>\u0000405 MHz), Wireless Medical Telemetry Service (WMTS) band (1427\u0000<inline-formula><tex-math>$-$</tex-math></inline-formula>\u00001432 MHz), and the Industrial, Scientific, and Medical (ISM) band (2.4\u0000<inline-formula><tex-math>$-$</tex-math></inline-formula>\u00002.4835 GHz). The on-body receiving antennas have a planar spiral structure with a size of 20 × 6.8 × 27 mm\u0000<inline-formula><tex-math>$^{3}$</tex-math></inline-formula>\u0000 and a planar meandered structure with a size of 42 × 10 × 1.6 mm\u0000<inline-formula><tex-math>$^{3}$</tex-math></inline-formula>\u0000, respectively, which are suitable for wearable terminals. The performance of the proposed antenna system is analyzed and validated using a muscle-equivalent model, a multi-layer tissue model, a numerical human model in simulations, and a liquid phantom in experiments. Simulation and experimental results show the good potential of the antenna system for intra-body communication scenarios such as wireless electronic capsules.","PeriodicalId":29955,"journal":{"name":"IEEE Journal of Electromagnetics RF and Microwaves in Medicine and Biology","volume":"8 4","pages":"332-343"},"PeriodicalIF":3.0,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-27DOI: 10.1109/JERM.2024.3401582
Guoliang Ren;Mengjun Wang;Hongxing Zheng;Erping Li
To enhance the efficiency of wireless power transmission for the implanted medical system, a human body surface conformal phase gradient metasurface (PGMS) has been designed in this letter. Based on geometric phase modulation, the PGMS can convert the spherical wave from the transmitting antenna into a plane wave, ensuring the electromagnetic wave perpendicular to human skin. Thereby the power transmission efficiency of the implanted system can be increased obviously. A three-layered cylindrical human tissue model, including skin, fat, and muscle layers, is used to analyze the performance of the PGMS. Simulation results show that the transmission coefficient amplitude of the metasurface element at 1.4 GHz exceeds 0.8. Then the spherical wave of the antenna converted into a plane wave is verified by a 3 × 3 PGMS array when the transmitting antenna is located 50 mm away. Finally, the measurement results have been obtained, which exhibit very good agreement with the simulation. The distinctive advantage of the designed PGMS lies in its flexibility, allowing it to be easily bent and conform to the contoured surfaces of the human body. Additionally, the PGMS offers seamless integration into various medical devices and implants, further enhancing its practicality. This research showcases the potential of the proposed PGMS in significantly enhancing wireless power transmission efficiency for implanted medical systems.
{"title":"Wireless Power Transmission Efficiency Improved by Conformal Phase Gradient Metasurface for Implanted Devices","authors":"Guoliang Ren;Mengjun Wang;Hongxing Zheng;Erping Li","doi":"10.1109/JERM.2024.3401582","DOIUrl":"https://doi.org/10.1109/JERM.2024.3401582","url":null,"abstract":"To enhance the efficiency of wireless power transmission for the implanted medical system, a human body surface conformal phase gradient metasurface (PGMS) has been designed in this letter. Based on geometric phase modulation, the PGMS can convert the spherical wave from the transmitting antenna into a plane wave, ensuring the electromagnetic wave perpendicular to human skin. Thereby the power transmission efficiency of the implanted system can be increased obviously. A three-layered cylindrical human tissue model, including skin, fat, and muscle layers, is used to analyze the performance of the PGMS. Simulation results show that the transmission coefficient amplitude of the metasurface element at 1.4 GHz exceeds 0.8. Then the spherical wave of the antenna converted into a plane wave is verified by a 3 × 3 PGMS array when the transmitting antenna is located 50 mm away. Finally, the measurement results have been obtained, which exhibit very good agreement with the simulation. The distinctive advantage of the designed PGMS lies in its flexibility, allowing it to be easily bent and conform to the contoured surfaces of the human body. Additionally, the PGMS offers seamless integration into various medical devices and implants, further enhancing its practicality. This research showcases the potential of the proposed PGMS in significantly enhancing wireless power transmission efficiency for implanted medical systems.","PeriodicalId":29955,"journal":{"name":"IEEE Journal of Electromagnetics RF and Microwaves in Medicine and Biology","volume":"8 4","pages":"325-331"},"PeriodicalIF":3.0,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142777591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-25DOI: 10.1109/JERM.2024.3374090
Md. Abdul Awal;Syed Akbar Raza Naqvi;Damien Foong;Amin Abbosh
The dielectric properties of normal and cancerous skin vary with frequency due to changes in water content and tissue composition. Developing a reliable microwave system for skin cancer detection requires accurate characterization of that change in the dielectric properties. A possible choice is the Cole-Cole model, which can accurately fit the measured dielectric data for tissues. However, fitting the non-linear Cole-Cole model parameters with the measured data requires a sophisticated optimization algorithm. This study proposes an adaptive weighted vector means optimization algorithm, which employs adaptive initialization, logarithmic spaces, and enhanced local search mechanism, resulting in improved accuracy with fewer iterations. The algorithm is evaluated using dielectric data from healthy skin, basal cell carcinoma, squamous cell carcinoma, and melanoma and is found to outperform other relevant algorithms. One of the salient features of this study is that a set of clinical melanoma dielectric data is acquired, analyzed, and physically interpreted in terms of relaxation frequency and dispersion across 0.3 GHz to 14 GHz. It is found that melanoma closely follows the second-order Debye model, which is a special case for the second-order Cole-Cole model with a zero-valued dispersion broadening parameter. Although melanoma data is obtained from one lesion because of the low incidence rate, the research findings will contribute to a better understanding skin cancer at microwave frequencies. A triangular plot, which shows model fitness accuracy and the number of iterations, is presented to summarize the advantages of the algorithm.
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Pub Date : 2024-03-22DOI: 10.1109/JERM.2024.3400471
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