This work details CMOS, bio-inspired, bio-compatible circuits which were used as synapses between an artificial neuron and a living neuron and between two living neurons. An intracellular signal from a living neuron was amplified, an integrate-and-fire neuron was used as a simple processing element to detect the spikes, and an artificial synapse was used to send outputs to another living neuron. The key structure is an electronic synapse which is based around a floating-gate pFET. The charge on the floating-gate is analogous to the synaptic weight and can be modified. This modification can be viewed as similar to long-term potentiation and long-term depression. The modification can either be programmed (supervised learning) or can adapt to the inputs (unsupervised learning). Since the technology to change the floating-gate weight has greatly improved, these weights can be set quickly and accurately. Intrinsic floating-gate learning rules were explored and the ability to change the synaptic weight was shown.

The explosive growth of wireless communication market has led the development of low-cost, highly-integrated wireless communication systems. Even though most blocks in the front-end have successfully been integrated by using the CMOS technology, it is still a formidable challenge to integrate the entire front-end. Thus, the objective of this research is to demonstrate the feasibility of the integrated front-end by using improved circuit techniques as well as the improved process technologies. This dissertation proposes an improved control scheme to enhance the high-power handling capability of an antenna switch. As a part of this research, an antenna switch controller for a GaAs antenna switch was first developed to enhance the performances of the GaAs antenna switch by using the boosted control voltage. To enhance the efficiency of the front-end, efficiency improvement techniques for the antenna switch controller has also been studied. With the suggested efficiency improvement techniques, a fully-integrated antenna switch was implemented using the SOI technology, and exceeding performances over many commercial products for watt-level high-power applications have been successfully demonstrated. As an effort to improve the efficiency of a power amplifier, a linear envelope detector was also implemented, and the results show that the envelope detector is suitable for dynamic biasing of the power amplifier. The research presented in this dissertation, thus, provides a low-cost and high-performance solution for highly-integrated RF front-end used in various wireless communication systems.

The objective of the proposed research is to analyze and develop energy optimized design techniques that can improve the operating efficiency for a wireless sensor device. To enhance the operating efficiency, all active functional blocks in a system should focus on energy conservation while achieving the required tasks. In addition, variations in the operating condition should be properly observed and compensated. Otherwise, a wireless sensor device would consume unnecessary energy for a given task or too little energy to meet the requirements. In this research, design strategies and some new circuit topologies are discussed in terms of ultra-low energy constraints. In particular, the signal processing unit, the memory unit, and the power unit in a conventional wireless sensor device will be main focus. As an example of the signal processing unit, a subthreshold current mode computation system has been designed and tested to prove the "low power consumption" feature of analog signal processing. For the memory unit, conventional SRAM cells are compared to a new fully-gated 10T-SRAM cell. For the power unit, a semi-active high-efficient CMOS rectifier with a reverse leakage control has been developed. It employs a cross-coupled NMOS pair and two leakage control comparators to reduce reverse charge leakage currents. In addition, the adaptive body bias control technique is utilized to improve the reliability of the rectifier. In addition, a novel link-variation sensing technique is proposed. The proposed technique can evaluate operational disturbances such as component mismatches and displacement variations so that the performance of a wireless sensor device in the actual environment can be close to the optimum without wasting an excessive amount of energy.

Thesis (Ph. D.)--University of Florida, 2005. / Title from title page of source document. Document formatted into pages; contains 157 pages. Includes vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 163-176).

Thesis (Ph. D.)--Brigham Young University. Dept. of Electrical and Computer Engineering, 2004. / Includes bibliographical references (p. 153-158).

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 102-109).

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 105-109).

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 146-149).

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 118-130).