This paper presents a fully wireless cardiac pressure sensing system. Food and Drug Administration (FDA) approved medical stents are explored as radiating structures to support simultaneous transcutaneous wireless telemetry and powering. An application-specific integrated circuit (ASIC), designed and fabricated using the Texas Instruments 130-nm CMOS process, enables wireless telemetry, remote powering, voltage regulation, and processing of pressure measurements from a microelectromechanical systems (MEMS) capacitive sensor. This paper demonstrates fully wireless-pressure-sensing functionality with an external 35-dB.m RF powering source across a distance of 10 cm. Measurements in a regulated pressure chamber demonstrate the ability of the cardiac system to achieve pressure resolutions of 0.5 mmHg over a range of 0-50 mmHg using a channel data-rate of 42.2 kb/s.
Glaucoma is a detrimental disease that causes blindness in millions of people worldwide. There are numerous treatments to slow the condition but none are totally effective and all have significant side effects. Currently, a continuous monitoring device is not available, but its development may open up new avenues for treatment. This work focuses on the design and fabrication of an active glaucoma intraocular pressure (IOP) monitor that is fully wireless and implantable. Major benefits of an active IOP monitoring device include the potential to operate independently from an external device for extended periods of time and the possibility of developing a closed-loop monitoring and treatment system. The fully wireless operation is based off using gigahertz-frequency electromagnetic wave propagation, which allows for an orientation independent transfer of power and data over reasonable distances. Our system is comprised of a micro-electromechanical systems (MEMS) pressure sensor, a capacitive power storage array, an application-specific integrated circuit designed on the Texas Instruments (TI) 130 nm process, and a monopole antenna all assembled into a biocompatible liquid-crystal polymer-based tadpole-shaped package.
Abstract-We report live animal studies that verify and quantify successful transocular transmission of data from a miniature low-power implant. To minimize damage, implantation within layers of the eye requires an ultrasmall device on a scale of just a few millimeters on each side and less than 500 m in thickness. A high-frequency transmitter integrated circuit (IC) was designed, fabricated, and bonded onto a board containing an antenna, matching network components, and interconnects. The transmitter must achieve sufficient efficiency to draw minimal power from the limited onboard storage array while outputting a sufficiently large signal to overcome tissue-induced attenuation. Two different versions of the system were developed, one using a low-temperature co-fired ceramic material for the substrate and the other using silicon. Animal studies performed using live rabbits followed by empirical measurements verified the feasibility of a wireless telemetry scheme for a low-power miniature ocular implant.Index Terms-Biological system modeling, biomedical applications of EM radiation, biomedical telemetry, implantable biomedical devices.
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