Aleksandar Marincic

Mode Tuning of Microwave Reasonator Loaded with Lossy Multilayer Dilectric

Multi-layer filled rectangular cavity resonances are investigated in this paper. A general computer program for the calculation of resonant frequencies has been developed. Characteristic equations are obtained on the basics of the transverse resonance method with impedance and admittance resonance conditions. The two resonance conditions give different results for lossy dielectric, which seems not to have been noticed before. Experimental results in the frequency range 0.5 to 1 GHz compares well with combined results for the two resonance conditions.

Identification of Resonant Modes in a Loaded Microwave Rectangular Cavity

In this paper identification of resonant modes in a rectangular cavity loaded with homogeneous dielectric layers was investigated. Computer programs were developed based on an approach that leads to a unique mode identification. Characteristic examples of mode identification are given.

Thermal images generated by a line-scanning technique: statistical properties

The analysis of statistical parameters of computer-generated therfial images by a line-scanning technique indicates an approach to efficient image transmission.

Tesla's contribution to radiowave propagation

We review Nikola Teslas contribution to radiowave propagation and wireless power transmission. Teslas patents, published and unpublished notes about radiowave propagation and wireless power transmission are less known, and if known to some extent, they are usually wrongly interpreted.

Wireless local area networks

Wireless local area networks are becoming more and more important due to increased interest in connection of mobile and portable computers mutually, or to the wired LANs. Wireless LANs come in three types: infrared (diffuse, line-of-sight), microwaves and radio. In order to anticipate future development, this paper systematised the design fundamentals of infrared systems, standardisation activities and characteristics of some representative market products.

Thermal-image generation by line-scanning technique: a new computer model

A new computer model for the generation of thermal images of a flat terrain by the line-scanning technique from a moving platform is presented. The model is based on a bottom-up simulation process and the pixel-by-pixel generation of infrared thermal images. The terrain is modeled by a periodic repetition of an arbitrary two-dimensional temperature distribution over a flat area. The double discrete Fourier series of the terrain temperature, including correlation length and the transfer function of the scanning optics, is used. Several computer-generated thermal images are produced to illustrate the model. The geometrical deformations, the space filtration, and the gray-level variation with the scanning angle on generated images are in agreement with theoretical predictions.

Nikola Tesla: 145 years of visionary ideas

The paper gives a short review of Teslas major inventions including the rotating magnetic field, the Tesla coil and transformer, and the power struggle between Edisons direct current systems and the Tesla-Westinghouse alternating current approach. It also looks at some of Teslas visionary ideas.

Microwave circuits based on six-port junction

This paper describes the procedure of microwave circuits construction based on double-Y junction, which is actually a six-port circuit. The procedure is based on S-matrix of lossless double-Y junction. It has been demonstrated how a double-Y junction can be modified into a double-Y balun and a 3 dB quadrature coupler by placing open and short circuits on appropriate ports of a double-Y junction.

Analysis of real feed probe influence to the resonant frequencies and field distribution in the cylindrical metallic cavity using 3D TLM method

For the example of the cylindrical metallic cavity with circular cross-section, the real excitation modeling, using TLM wire node, is presented. The small wire conductor, as an excitation form, is used according to the wanted type of mode in the cavity. The modeling process is described and the obtained TLM numerical results are compared with the experimental ones, to the aim of verification of the method. Besides, the influence of length and radius of real feed probe to the resonant frequencies of TM and TE modes in frequency range f=[1.5-3.5] GHz is analysed. TLM results, in the case of empty cavity with real excitation probe, are compared with results calculated by using the theoretical approach, that is TLM simulator with impulse excitation. Finally, field strength versus length of real feed probe are investigated and the appropriate conclusions are given.

Matrix analysis of transmission line with inserted Pupin's coils

Theory of periodically loaded transmission lines, allowing for significant reduction of attenuation within the baseband telephone signal transmission, is presented. This approach, known as Pupin loading, is achieved by the use of discrete inductance coils equally distributed along the line. Full wave matrix analysis of such pupinized transmission line is done in order to discuss an influence of pupins coils inclusion on line transmission and bandwidth. Within this analysis, different number of equally inserted coils per wavelength corresponding to the maximum frequency of interest and different values of heaviside criterion fulfillment factor, introduced by the authors, are considered.