Wavelet transform modeling of electomagnetic waves in a waveguide

In this thesis, electromagnetic waves radiating in a waveguide are modeled byWavelet Transform. Electromagnetic waves can be modeled by using severaltechniques. One of the basic techniques, Fourier Transform, includes only thefrequency information of the signal. On the other hand, for non-stationarysignals time information is as necessary as frequency information. One of thedeveloped techniques for this purpose, Short Time Fourier Transform (STFT)can give both frequency and time information. In this method analysis isrealized with the shift of a constant length window and since the length of thewindow is constant the desired frequency resolution cannot be obtainedgenerally. To overcome these problems Wavelet Transform is developed.Wavelet Transform facilitates the investigation of the modeled electromagneticwaves, saves time and memory storage. The flexible structure of wavelettransform offers many options for the optimization of analysis results. In thiswork, a transform filter and an inverse transform filter is applied to the entryand end of the waveguide, respectively. The behaviour of electromagnetic wavesin the waveguide is simulated by using Finite Differences Time Domain (FDTD)method. For the graphical visualization of the modes excited in the waveguideMatlab software is used. For different waveguide modes and frequencies severalresults are obtained. It is shown that an optimal analysis can be obtained bycomparing the results of different wavelet types.Key words :Wavelet transform, Waveguide, Electromagnetic wave,Matlab