IEEE Journal of Electromagnetics RF and Microwaves in Medicine and Biology has been selected for inclusion in the Web of Science

Feature Article

The microwave auditory effect

James C. Lin

Review on Advanced Short-Range Multimode Continuous-Wave Radar Architectures for Healthcare Applications

José-María Muñoz-Ferreras, Zhengyu Peng, Roberto Gómez-GarcíaChangzhi Li

Take-Home Messages
Original Research Paper
Heart ID: Biometric Identification Using Wearable MIMO RF Heart Sensors

Thomas B. Conroy, Xiaonan Hui, Pragya Sharma, Edwin C. Kan.

Biometric identification (ID) has become increasingly prevalent in the digital era. Static biometric methods, such as fingerprint and facial recognition are widely accepted, yet generally vulnerable to targeted presentation attacks.

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Current development has expanded to dynamic biometrics, such as gait and electrocardiogram, that enable continuous authentication and are significantly more resistant to presentation attacks. However, dynamic biometrics often involve cumbersome acquisition which restricts their widespread use. Here, we introduce Heart ID, a novel dynamic biometric system that uses near-field coherent sensing (NCS) with a multiple-in multiple-out (MIMO) radio-frequency (RF) antenna setup to non-invasively acquire detailed recordings of internal cardiac dielectric boundary motion over clothing. NCS couples localized energy to the heart to derive interpersonal structural differences, while MIMO significantly increases the biometric entropy compared to single-point observation. We performed a human study of 20 subjects as well as 2 longitudinal evaluations, and employed an unsupervised feature extraction method to explore the ID performance of this new biometric. We found an ensemble classification approach using features derived from unsupervised learning can achieve accuracy exceeding 99% at a 40-second epoch.
Original Research Paper
Wireless and Zero-Power Trans-Cardiac Link With Antennified Aortic Valve Bioprostheses

Federica Naccarata, Cecilia Occhiuzzi, Roberto Verzicco, Gaetano Marrocco.

Valvular heart diseases are one of the most common complications in the cardiovascular system.

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To restore the correct cardiac activity, the failing native heart valve is surgically replaced with a prosthesis. Unfortunately, it often undergoes physio-pathological processes after implantation, including the risks of functional and structural deterioration. Periodic monitoring is hence mandatory all along the life of the patient. As standard screenings are intrusive, this paper proposes a method to exploit the peculiar form-factor of the internal metallic stent of a bioprosthesis as a natural energy harvester to achieve a reliable wireless trans-cardiac RFID-based, battery-free, communication link with no relevant change to the valve. Simulations and tests with a mock-up demonstrate that a robust link with a small size on-skin patch antenna is feasible notwithstanding potential user-specific placement as well as misalignment between the antennas.
Original Research Paper
Wirelessly Powered 3-D Printed Headstage Based Neural Stimulation System for Optogenetic Neuromodulation Application

Dipon K. Biswas, Nabanita Saha, Ifana Mahbub.

This work presents a miniaturized wireless power transfer (WPT) system integrated with a neuromodulation headstage for duty-cycled optical stimulation of freely moving rodents.

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The proposed WPT system is built using the commercially available off-the-shelf components (COTS) for the optogenetic neuromodulation system consisting of a bridge rectifier, a DC-DC converter, an oscillator circuit, an LED driver, and a μLED. The total power consumption of the stimulation system is 14 mW which is provided using the WPT method. The WPT system includes a novel transmitter (TX) coil implemented on a printed circuit board (PCB), and a solenoid receiver (RX) coil wrapped around a customized 3-D printed headstage. The proposed TX coil is designed in such a way that the magnetic field all across the TX coil is sufficient to provide the required power to the optical stimulation system that is worn as a headstage by the freely moving rat. The headstage device’s dimension is 18.75 mm × 21.95 mm, weighing 4.75 g. The ratio of the weight of the headstage and rat is 4.75:300. The proposed system is able to achieve a maximum overall efficiency of ∼63% at 5 cm separation between the TX and RX coils, where the maximum power transfer efficiency (PTE) of the WPT system is ∼88% and the power conversion efficiency (PCE) of the rectifier is 71.6%. The proposed system with reconfigurable stimulation frequency is suitable for exciting different brain areas for long-term health monitoring.
Original Research Paper
Implementation of Thinned Array Synthesis in Hyperthermia Treatment Planning of 434 MHz Phased Array Breast Applicator Using Genetic Algorithm

Divya Baskaran, Kavitha Arunachalam.

Genetic algorithm-based array thinning technique is investigated in this paper to study the performance of our 18-element 434 MHz phased array breast applicator when driven by reduced number of active antennas.

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Selective power deposition ability was assessed for 18, 15, 12, and 9 active antennas on 25 patient models with varying characteristics. The average hotspot to target quotient of 18-, 15-, 12-, and 9-antenna excitation in 25 patient models was 1.18, 1.09, 1.09, and 1.13, respectively. The average temperature in 50% tumor volume for 18-, 15-, 12-, and 9-antenna excitation was 42.42 °C, 42.48 °C, 42.49 °C, and 42.48 °C, respectively. The temperature induced in tumor and healthy tissues is similar for varying number of active channels. However, the amount of power consumed was 25.2%, 53.9%, 97.9% higher for 15, 12, 9 active antennas compared to the filled array. Antenna array with 12 active elements was chosen as the optimal combination as it provided selective tumor heating with good tradeoff between number of channels and power consumption. The heating ability of the thinned array was assessed for 50% reduction in the number of active antennas on patient derived heterogeneous breast phantoms for five tumor target locations. The good agreement between simulated and measured thermal distributions demonstrate the selective heating ability of our phased array applicator for 50% reduction in hardware resources. The study outcome enables us to realize a cost-effective hyperthermia treatment delivery system.