Thesis (M.S.)--Oregon State University, 2005. / Printout. Includes bibliographical references (leaf 56). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 80-84). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 49-50). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 71-76). Also available on the World Wide Web.

Wireless communication is part of our daily life in several applications, such as cell phones, wireless printers, sensors, etc. Each wireless device requires at least one antenna to communicate with other devices. In 2002, Federal Communications Commission (FCC) assigned a frequency spectrum from 3.1 GHz to 10.6 GHz for ultra-wideband communications. Several narrowband antennas require to cover the entire range. Unlike narrowband antennas, ultra-wideband antennas need to cover the wide frequency band. This research mainly focuses on physically small antenna designs. The first antenna discussed in this dissertation is a dual, triple trident antenna with dimensions 24 mm × 28 mm × 0.785 mm, which will operate from 3 GHz to 12.15 GHz [58]. The first antenna consists of six tridents symmetrical along the vertical direction. The second antenna design is a novel rectangular ring ultra-wideband antenna [59]. Large antennas operate for low frequency, and small antennas work for high frequency. The number of rings increased in wideband antenna to 9 from 4 to check the design methodology. The rectangular ring ultra-wideband antenna has dimensions 24 mm × 26 mm × 1.52 mm. This antenna operates from 3.12 GHz to 12.85 GHz. The third antenna design is an ultra-wideband dual square trident planar antenna. This antenna’s overall size is 26 mm × 24 mm × 1.56 mm [60]. This antenna has impedance bandwidth from 3.65 GHz to 12.50 GHz. The fourth antenna design is an ultra-wideband antenna with a band notch from 5.05 GHz to 5.9 GHz [61]. This antenna consists of two tridents and two split-ring resonators along the microstrip feed line. The overall size of this antenna 26 mm ×24 mm × 1.53mm. Simulations are carried out using the CST microwave studios® to analyze the antenna performance. Experiments are conducted to verify the simulated results using vector network analyzers for impedance and anechoic antenna chamber for radiation characteristics of the antenna. All four antennas are excellent for the wireless device due to their compact size and planar designs.

In recent years, microwave ablation therapy has become widely investigated as an alternative treatment to cancer. This method is one of the newest forms of ablation techniques for the removal of tumors and is minimally invasive compared to alternative treatments. One drawback to many of the current microwave ablation systems is the narrowband nature of the antennas used for the probe, such as dipole antennas. This study aims to compare ablation results of both ultra-wideband and narrowband ablation techniques. An ultra-wideband ablation probe is designed that operates from 400MHz to 2.6GHz and are compared to two designed narrowband ablation probes that operate at 915MHz and 2.4GHz, respectively. These ablation probes are tested in tissue mimicking gels and porcine liver. Provided results for this thesis will include probe designs, simulation results, and ablation experiments.

No description available.

No / Near field imaging using microwaves in medical applications has gained much attention recently as various researchers have shown its capability and accuracy in identifying features of interest compared to well-known screening tools. This paper documents microwave imaging experiments for breast cancer detection. A simple phantom consisting of a plastic container with a low dielectric material imitating fatty tissue and a high dielectric constant object emulating tumor is scanned with a UWB microstrip antenna between 4 to 8 GHz. The measured results indicate that the prototype is a good candidate for imaging application.

Im Energie- und Produktionssektor ist für das Heben von Potentialen für Energie- und Ressourceneffizienz von Prozessen viel Sensorik notwendig. Verkabelte Systeme sind dafür aufgrund hoher Installationskosten und geringer Flexibilität oftmals nicht geeignet. Notwendig ist ein kostengünstiges, nachrüstbares und energieautarkes drahtloses Sensornetzwerk (WSN – Wireless Sensor Network) für Energie- und Condition Monitoring (Strom-, Spannungs-, Vibrations-, Temperaturmessung). Ein wesentlicher Innovationsschritt ist die Anwendung und intelligente Kombination neuer Funktechnologien wie UWB (Ultra-Wideband) und LoRa (Long Range) sowie von Energy Harvesting zum autarken Betrieb der Sensorknoten. Mit einem systemischen Ansatz der Kombination vorgenannter Komponenten wird das Sensornetz hinsichtlich Verlässlichkeit, Skalierbarkeit und Flexibilität in Bezug auf die Anwendung optimiert. Der Proof-of-Concept (PoC) wird mit einem Testaufbau des WSN im Labormaßstab an konkreten Use Cases aus den Bereichen Windkraftanlagen und industrieller Produktion erbracht.