Advances and updates in medical applications utilizing microwave techniques and technologies are reviewed in this paper. The article aims to provide an overview of enablers for microwave medical applications and their recent progress. The emphasis focuses on the applications of microwaves, in the following order, for 1) signal and data communication for implants and wearables through the human body, 2) electromagnetic energy transfer through tissues, 3) noninvasive, remote or in situ physical and biochemical sensing, and 4) therapeutic purposes by changing tissue properties with controlled thermal effects. For signal and data communication and wireless power transfer, implant and wearable applications are discussed in the categories of pacemakers, endoscopic capsules, brain interfaces, intraocular, cardiac and intracranial pressure sensors, neurostimulators, endoluminal implants, artificial retina, smart lenses, and cochlear implants. For noninvasive sensing, remote vital sign radar, biological cell probing, magnetic resonance and microwave imaging, biochemical, blood glucose, hydration and biomarker sensing applications are introduced. For therapeutic uses, the developments of microwave ablation, balloon angioplasty, and hyperthermia applications are reviewed. The scopes of this article mainly concentrate on the research and development efforts in the past 20 years. Recent review articles on specific topics are cited with accomplishment highlights and trends deliberated. At the end of this article, a brief history of the IEEE Microwave Theory and Techniques Society (MTT-S) Biological Effects and Medical Applications committee and the contributions by its members to the promotion and advancement of microwave technologies in medical fields are chronicled.

In this letter, wireless charging chests suitable for smart garments are analyzed and optimized. The coil structure is optimized to generate a uniform magnetic field in a variety of drawer sizes. With the hybrid Helmholtz–solenoid coil structure, the variation of coupling factor is reduced from 78.2% to 26.4% as compared with solenoidal coil. Two design approaches for multidrawer chest are examined. In the first approach, the coils are optimized for individual drawers. In the second approach, the coils are optimized by considering the entire drawer chest. The measurement results show that the second approach further reduces the variation of charging current of receiver coils placed at different locations.

The SARS-CoV-2 pandemic has had a significant impact worldwide. Currently, the most common detection methods for the virus are polymerase chain reaction (PCR) and lateral flow tests. PCR takes more than an hour to obtain the results and lateral flow tests have difficulty with detecting the virus at low concentrations. In this study, 60 clinical human saliva samples, which included 30 positive and 30 negative samples confirmed with RT-PCR, were screened for COVID-19 using disposable glucose biosensor strips and a reusable printed circuit board. The disposable strips were gold plated and functionalized to immobilize antibodies on the gold film. After functionalization, the strips were connected to the gate electrode of a metal-oxide-semiconductor field-effect transistor on the printed circuit board to amplify the test signals. A synchronous double-pulsed bias voltage was applied to the drain of the transistor and strips. The resulting change in drain waveforms was converted to digital readings. The RT-PCR-confirmed saliva samples were tested again using quantitative PCR (RT-qPCR) to determine cycling threshold (Ct) values. Ct values up to 45 refer to the number of amplification cycles needed to detect the presence of the virus. These PCR results were compared with digital readings from the sensor to better evaluate the sensor technology. The results indicate that the samples with a range of Ct values from 17.8 to 35 can be differentiated, which highlights the increased sensitivity of this sensor technology. This research exhibits the potential of this biosensor technology to be further developed into a cost-effective, point-of-care, and portable rapid detection method for SARS-CoV-2.

Modern microwave radar technologies and systems are taking important roles in healthcare, security, and human-machine interface by remote sensing of human life activities. This paper first reviews the developments in the past decade on the sensing front-end, transponder tag, and leveraging of other wireless infrastructure such as Wi-Fi. Based on the state-of-the-art engineering technologies, several emerging applications will then be studied, including continuous authentication, behavior recognition, human-aware localization, occupancy sensing, blood pressure monitoring, and sleep medicine. As radio frequency spectrum becomes a scarce resource, the allocation and spectrum sharing of life activity sensing bandwidth with other wireless infrastructures will be discussed. Several future research directions will be laid out to solve challenges for ubiquitous deployment of these sensing technologies at the human-microwave frontier.

Detection of the SARS-CoV-2 spike protein and inactivated virus was achieved using disposable and biofunctionalized functional strips, which can be connected externally to a reusable printed circuit board for signal amplification with an embedded metal-oxide-semiconductor field-effect transistor (MOSFET). A series of chemical reactions was performed to immobilize both a monoclonal antibody and a polyclonal antibody onto the Au-plated electrode used as the sensing surface. An important step in the biofunctionalization, namely, the formation of Au-plated clusters on the sensor strips, was verified by scanning electron microscopy, as well as electrical measurements, to confirm successful binding of thiol groups on this Au surface. The functionalized sensor was externally connected to the gate electrode of the MOSFET, and synchronous pulses were applied to both the sensing strip and the drain contact of the MOSFET. The resulting changes in the dynamics of drain waveforms were converted into analog voltages and digital readouts, which correlate with the concentration of proteins and virus present in the tested solution. A broad range of protein concentrations from 1 fg/ml to 10 μg/ml and virus concentrations from 100 to 2500 PFU/ml were detectable for the sensor functionalized with both antibodies. The results show the potential of this approach for the development of a portable, low-cost, and disposable cartridge sensor system for point-of-care detection of viral diseases.

RF surface coils are commonly used as receivers in Magnetic Resonance Imaging (MRI) systems to acquire sensitive signals from the human body. These coils rely on cables for power and transferring information from the patient to the computer for processing. Higher image quality and faster scan times are possible by using an array of surface coils, and there is a constant need for high-density surface coil arrays. Each array element utilizes at least three cables and, increasing the number of elements in the array also increases the number of cables, making the cable bundle bulkier. This makes the placement of cables complicated for the operators and may cause patient harm when improperly positioned. Wireless technologies can eliminate cables, and this paper proposes a novel design for harvesting the ambient RF energy present during the transmit phase of the MRI system operation. After introducing the surface coil's building blocks, the importance of the decoupler as a mechanism for safety and image quality is detailed. The paper presents the analysis and design of an RF energy harvesting circuit that couples to the decoupler circuit. Its performance is tested both in simulation and the Philips Ingenia 3.0 T MRI system. The results show that the circuit successfully harvests energy, up to 1 W, during the MRI's transmit phase without any adverse effects on the decoupler or surface coil. To make energy harvesting (EH) beneficial, a new GaN -based FET switch that consumes low power is also proposed.

In this paper, four kinds of conductive threads were studied and their uses on embroidered coils for wireless charging system were examined. The results show that the embroidered coils can achieve a quality factor of at least 3 without compromising the mechanical performance of the textile. A coil was embroidered directly on a T-shirt which shows that the fabrication of embroidered receiver (RX) coil might be integrated into the clothing manufacturing process.

Wireless power transfer (WPT) technologies have been adopted by many products. The capability of charging multiple devices and the design flexibility of charging coils make WPT a good solution for charging smart garments. The use of an embroidered receiver (RX) coil makes the smart garment more breathable and comfortable than using a flexible printed circuit board (FPCB). In order to charge smart garments as part of normal daily routines, two types of wireless-charging systems operating at 400 kHz have been designed. The one-to-one hanger system is desired to have a constant charging current despite misalignment so that users do not need to pay much attention when they hang the garment. For the one-to-multiple-drawer system, the power delivery ability must not change with multiple garments. Additionally, the system should be able to charge folded garments in most of the folding scenarios. This paper analyses the two WPT systems for charging smart garments and provides design approaches to meet the abovementioned goals. The wireless-charging hanger is able to charge a smart garment over a coupling variance kmaxkmin=2 with only 21% charging current variation. The wireless-charging drawer is able to charge a smart garment with at least 20 mA under most folding scenarios and three garments with stable power delivery ability.

Rapid Sars-Cov-2 Virus Detection Using Modular Transistor-Based Biosensor Platform with Disposable Test Strips, Minghan Xian, Hao Luo, Xinyi Xia, Chaker Fares, Patrick Carey, Fan Ren, Siang-Sin Shan, Yu-Te Liao, Josephine F Esquivel-Upshaw, Jenshan Lin, Steven C Ghivizzani, Stephen J Pearton

Oren Eliezer Transactions Chair – TMTT Fred Lee Industry Liaison Hongtao Xu Asia Pacific Liaison Transactions Chair – JSSC Mohyee Mikhemar Secretary Andre Hanke Panel Sessions Chair François Rivet SessionOrganizationChair European Liaison Mona Hella Workshops Co-Chair Danilo Manstretta Workshops Chair Amin Arbabian Publicity Co-Chair Hua Wang Publications Co-Chair Gernot Hueber Publications Chair Osama Shana’a TPC Co-Chair Brian Floyd TPC Chair Waleed Khalil General Chair

In this paper, we report a method of using embroidery to fabricate textile inductor coils for wireless charging of wearable sensor devices on smart garments. Electrical properties of embroidered coils are measured and compared with simulation. A process of making embroidered coils with crossover connections is proposed. An embroidered coil array structure is designed and tested in two wireless charging systems and the results show that it can charge a lithium-ion battery with currents ranging up to 100 mA.

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Wireless-charging hanger and drawer systems with conductive textile receiver coils are reported in this paper. Both systems can be used to conveniently charge Li-ion batteries in smart garments with embedded sensors. The receiver coils fabricated with conductive textile greatly enhance comfort, flexibility, and foldability of garments. The frequency used for wireless charging is 400 kHz. For the hanger system, the maximum charging power can reach 200 mW with 25.5% dc-dc efficiency. For the drawer system, maximum charging power for one garment is 307 mW with 10.5% dc-dc efficiency.

In this paper, the acoustic-induced vibration phenomenon is studied with a 100-GHz high-sensitivity Doppler radar system using double-sideband 1ow-IF architecture. Based on the forced vibration theory, by stimulating the object with a frequency-swept sound wave, object’s vibration gets stronger as the sound frequency approaches its natural vibration frequency. In this work, a frequency-stepped audio signal is played to induce the vibration of an aluminum foil sheet. By varying audio frequency from 50 to 450 Hz, the aluminum foil’s vibration is detected by the 100-GHz radar system. According to detection results, the variation of the aluminum foil’s vibration strength during damped and undamped regions are successfully observed, and the aluminum foil’s natural vibration frequency is estimated to be 119 Hz. This experimental research proves that high-frequency Doppler radar could be utilized for future acoustic-based material study.

This article presents a fully integrated 100-GHz continuous-wave Doppler radar transceiver with the double-sideband low-intermediate-frequency (IF) architecture for mechanical vibration and vital sign detection. Fabricated in a 65-nm CMOS process, the whole radar chip transceiver consumes 262 mW with a size of 0.9 mm $\times2.0$ mm. Instead of utilizing a fundamental 100-GHz voltage controlled oscillator (VCO) in the chip, a push–push frequency doubler with the 50-GHz external source is adopted to drive the transceiver. Under a dedicated design on the system architecture and circuit blocks, the chip could transmit 4-dBm saturated power ( $P_{\mathrm {sat}}$ ) over 93–105 GHz with a 40-mV 1-kHz IF carrier and achieve good I/Q performance of phase mismatch <1° and amplitude mismatch < 1 dB over 95–104 GHz. With a–36-dBm RF input from 99 to 104 GHz, the IF differential output amplitude varies from 470 to 680 mV. To validate the detection ability, a probe-station-based test setup is proposed. Benefiting from the short wavelength at 103 GHz, this radar system successfully detects the mechanical vibration of 1- $\mu \text{m}$ displacement from 1.5 m, the human vital-sign signal from 2 m, and even a small bullfrog’s hybrid respiratory motion from 0.6 m. To the best of our knowledge, this is the first 100-GHz CMOS Doppler radar transceiver chip with the low-IF architecture for the biological vital sign detection.

This paper presents a portable readout interface IC for electrochemical sensing. The circuit conducts the chronoamperometry measurement by generating two stimulus pulses. A current-to-frequency converter senses the current change from the bio-sensing transistor built by two gold electrodes at the gate. The results are measured by using a time-to-digital converter. The readout circuit consumes 14$\mu$ W at a 1.2V supply, and its function is verified under the potassium ferricyanide test. The limit of detection is 1nM in a concentration range of 1mM.

There are opportunities for development of modularized, inexpensive protein biomarker sensors in clinical applications. In this review we focus on two of these, namely early diagnosis of acute myocardial infarction (AMI) and detection of cerebral spinal fluid (CSF). Evaluation of patients with acute chest pain is challenging due to the heterogeneity of the underlying conditions, leading to patients with AMI being mistakenly sent home from emergency rooms or those at low risk for an adverse cardiac event being unnecessarily admitted without precise cardiac biomarker testing. Cardiac troponin I (cTnI) in cardiac muscle tissue is a standard clinical biomarker for AMI, as its concentration rises quickly in the blood during release from myocardial cells following cell death. The time-dependence of the cTnI concentration is the basis of antigen-antibody methodologies such as radioimmunoassay and enzyme-linked immunosorbent assay (ELISA). These methods are time consuming, leading to delays in diagnosis and higher costs. The challenge is to develop a real-time, accurate, low-cost point-of-care heart attack sensor. The coefficient of variation must be precise, within the parameters established by the American College of Cardiology. Similarly, leakage of cerebrospinal fluid (CSF) is a critical condition with a high risk of meningitis and potential mortality. The primary methods of detection for the biomarker beta 2-Transfferin (B2T) are immunofixation electrophoresis (IFE) and ELISA. Consistent IFE results down to 2 mu g/mL can be obtained in patient samples, but requires a minimum 2.5-hour testing period, which is not expedient for real time feedback during surgery in or around the central nervous system. Additionally, to achieve good sensitivity and handle the inherently low concentration of B2T in CSF, lab procedures require samples to be concentrated or run in duplicate to ensure accurate detection. Real time turnaround is on the order of days. To alleviate the slow turn-around times, there is strong interest in electronic detection methods for proteins using biologically functionalized transistors, which provide an electronic readout and are readily integrated with wireless data transmission. (C) The Author(s) 2019. Published by ECS.