Obstructive sleep apnea (OSA), a common sleep disorder disease, affects millions of people. Without appropriate treatment, this disease can provoke several health-related risks including stroke and sudden death. A variety of treatments have been introduced to relieve OSA. The main present clinical treatments and undertaken research activities to improve the success rate of OSA were covered in this paper. Additionally, guidelines on choosing a suitable treatment based on scientific evidence and objective comparison were provided. This review paper specifically elaborated the clinically offered managements as well as the research activities to better treat OSA. We analyzed the methodology of each diagnostic and treatment method, the success rate, and the economic burden on the world. This review paper provided an evidence-based comparison of each treatment to guide patients and physicians, but there are some limitations that would affect the comparison result. Future research should consider the consistent follow-up period and a sufficient number of samples. With the development of implantable medical devices, hypoglossal nerve stimulation systems will be designed to be smart and miniature and one of the potential upcoming research topics. The transcutaneous electrical stimulation as a non-invasive potential treatment would be further investigated in a clinical setting. Meanwhile, no treatment can cure OSA due to the complicated etiology. To maximize the treatment success of OSA, a multidisciplinary and integrated management would be considered in the future.

Inductive link intended to deliver energy to implantable devices is recently becoming a popular method. To improve link efficiency, the compensated capacitors are adopted to resonate at the same frequency with the power transfer frequency on both sides. However, there is limited research on link efficiency and output power concerning quality factors, the selection between serial–parallel (SP) and serial–serial (SS) topologies, as well as coil design. This study delves into the efficiency of SP and SS topologies using rigorous mathematical derivations with reflected impedance models in terms of quality factors. It introduces a selection factor to help choose topology based on link efficiency. Results show that SS is better when the load quality factor ( $Q_{L}$ ) is lower than the selection factor, and vice versa. The study also examines the performance limits of both topologies concerning frequency, inductance, and load impedance. It proposes a specific $Q_{L}$ for maximum efficiency and a coil design procedure considering specific absorption rate limitations. By leveraging simulations and the design procedure, the study manufactures a pair of flexible coils for biomedical use. The designed link achieves a 62.99% efficiency under a 500 $\Omega$ load, with an overall efficiency of 46.96% including a passive rectifier.

The recent COVID-19 pandemic has caused tremendous damage to the social economy and people’s health. Some major issues fighting COVID-19 include early and accurate diagnosis and the shortage of ventilator machines for critical patients. In this manuscript, we describe a novel solution to deal with COVID-19: portable biosensing and wearable photoacoustic imaging for early and accurate diagnosis of infection and magnetic neuromodulation or minimally invasive electrical stimulation to replace traditional ventilation. The solution is a closed-loop system in that the three modules are integrated together and form a loop to cover all-phase strategies for fighting COVID-19. The proposed technique can guarantee ubiquitous and onsite detection, and an electrical hypoglossal stimulator can be more effective in helping severe patients and reducing complications caused by ventilators.

This letter presents a new design of microwave differentiators using coupled-resonator network. It is synthesized using coupling matrix techniques in the low-pass domain and subsequently transformed and implemented in the bandpass domain. Two numerical examples and one experimental validation are provided to illustrate the approach, which finally validates the proposed approach.

A novel microwave sensor for non-invasive blood glucose monitoring has been proposed in this paper. In order to inspect small variation in glucose density of capillary and evaluate the blood glucose level effectively for hypertension patient, the novel sensor should be sensitive with the dielectric constant of the detected medium, so one miniature monitoring antenna with a symmetrical network and electric properties may be promising choice contrast to the conventional microstrip patch, which doesn't demand for rigorous placement gesture. Referring to spiral structure and microstrip antenna, four-arm spiral microstrip antenna fed with a coaxial line is designed and simulated. It has a central frequency of 5GHz with a high quality factor and narrow bandwidth of 1.8%. To verify the supposed sensitivity and effectivity, some medium with different permittivity is attached on the surface and simulated. Small shift of the resonant frequency has been observed by virtue of the little changes of 1% in dielectric constant. The interesting phenomenon will be a good basis for further processing to extract the actual glucose level. More comparison and studies will be later investigated through fine simulations and experiments.