Student:	Yasin Oğuz
Supervisor:	Yrd. Doç. Dr. Haydar Kaya
Department:	Elektrik-Elektronik Müh.
Institution:	Graduate School of Natural and Applied Sciences
University:	Karadeniz Technical University, Turkey

Title of the Thesis:	Designing Waveform and Compensating Corruptive Influence of Antenna System in Ultra Wideband Systems
Level:	Ph.D.
Acceptance Date:	16/7/2008
Number of Pages:	135
Registration Number:	Di648

Summary:

Systems that use UWB technology based on communication with baseband signals

of very short duration recently attract attention in communication and radar application,

and thereof have been improving rapidly. Because UWB signals occupy a spectrum that is

spread about very wide frequency band, one of the principal issues that need to be

considered in UWB applications is the frequency allocation. In order to minimize or

prevent possible distorting interferences with existing communication systems, spectral

distribution of mandatory EIRP limit values has been determined by FCC in UWB

applications. Spectral power distributions of UWB signals used for any UWB application

have to be suitable to the mask that has been determined by FCC. In this study firstly, a

linear signal combination model has been designed and needful mathematical equations

have been formed to generate signals possessing spectral power distribution that is suitable

to a designated EIRP mask and has high spectrum utilization efficiency.

In UWB radar and communication applications, another major problem is sufficient

antenna usage for high efficiency propagations of UWB signal. Ideally, UWB transmitter

and receiver antenna system is desired to have a flat amplitude response in accordance with

frequency in operation frequency band. Because all antenna’s properties strongly depend

on the frequency, the transmitted waveform is filtered by the antenna structure. Deviations

from ideal situation that occurred in the filter characteristic known as antenna transfer

function cause distortions in spectral distribution of input signal.

In this thesis, an optimization study has been done to minimize influence of

deviations from ideal situation in spectral amplitude distribution of antenna transfer

function in UWB applications. A transfer function optimization model and solution have

been presented in order to obtain pre-input signals which change input waveform properly

to make spectral power distribution of UWB signal in antenna output remain the same. The

corruptive influence of antenna system has been highly compensated with proposed model.

Key Words: UWB, Pulse Shaping, Waveform Design, Antenna Transfer Function,

Optimization.