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Wide-Range Highly-Efficient Wireless Power Receivers for Implantable Biomedical Sensors

Wireless power transfer (WPT) is the key enabler for a myriad of applications,
from low-power RFIDs, and wireless sensors, to wirelessly charged electric vehicles,
and even massive power transmission from space solar cells. One of the major challenges in designing implantable biomedical devices is the size and lifetime of the
battery. Thus, replacing the battery with a miniaturized wireless power receiver
(WPRx) facilitates designing sustainable biomedical implants in smaller volumes for
sentient medical applications. In the first part of this dissertation, we propose a miniaturized, fully integrated, wirelessly powered implantable sensor with on-chip antenna, designed and implemented in a standard 0.18μm CMOS process. As a batteryless device, it can be implanted once inside the body with no need for further invasive surgeries to replace batteries. The proposed single-chip solution is designed for intraocular pressure monitoring (IOPM), and can serve as a sustainable platform for implantable devices or IoT nodes. A custom setup is developed to test the chip in a saline solution with electrical properties similar to those of the aqueous humor of the eye. The proposed chip, in this eye-like setup, is wirelessly charged to 1V from a 5W transmitter 3cm away from the chip.
In the second part, we propose a self-biased, differential rectifier with enhanced
efficiency over an extended range of input power. A prototype is designed for the
medical implant communication service (MICS) band at 433MHz. It demonstrates
an efficiency improvement of more than 40% in the rectifier power conversion efficiency
(PCE) and a dynamic range extension of more than 50% relative to the conventional
cross-coupled rectifier. A sensitivity of -15.2dBm input power for 1V output voltage
and a peak PCE of 65% are achieved for a 50k load. In the third part, we propose
a wide-range, differential RF-to-DC power converter using an adaptive, self-biasing
technique. The proposed architecture doubles the dynamic range of conventional
rectifiers. Unlike the continuously self-biased rectifier proposed in the second part,
this adaptive rectifier extends the dynamic range while maintaining both the high
PCE peak and the sensitivity advantage of the conventional cross-coupled scheme,
and can operates in the GHz range.

Identiferoai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/621866
Date11 1900
CreatorsOuda, Mahmoud
ContributorsSalama, Khaled N., Computer, Electrical and Mathematical Science and Engineering (CEMSE) Division, Alshareef, Husam N., Shamim, Atif, Volakis, John
Source SetsKing Abdullah University of Science and Technology
LanguageEnglish
Detected LanguageEnglish
TypeDissertation
Rights2017-12-01, At the time of archiving, the student author of this dissertation opted to temporarily restrict access to it. The full text of this dissertation became available to the public after the expiration of the embargo on 2017-12-01.

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