2001/4

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    Solenoid above Ground Plane - Equivalent Circuit
    (Společnost pro radioelektronické inženýrství, 2001-12) Hoffmann, K.; Vajtr, J.
    Wide-band vector measurements of transmission structures formed by solenoids with 2, 4 and 6 turns above ground plane were performed in the frequency band 45 MHz to 18 GHz. Novel equivalent circuits of these structures were designed. The equivalent circuits fit the measured data very well in the frequency band DC to 11 GHz. Comparison with models known up to now are given.
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    The Laboratory of Wireless and Mobile Communications
    (Společnost pro radioelektronické inženýrství, 2001-12) Hanus, S.
    The paper presents the basic information about establishing of the laboratory for Mobile Communications on the Dept. of Radio Electronics, Brno University of Technology. This information allows to experts from the practice to obtain the general notion about the extent of theoretical knowledge and practical experiences of our students in this field. This information can be also useful for the specialists from universities comparing simple their pedagogical activity in this field respecting the activity in another institute.
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    Arbitrary Q-factor Dielectric Resonator
    (Společnost pro radioelektronické inženýrství, 2001-12) Hoffmann, K.; Sokol, V.; Skvor, Z.
    New circuit component, active resonator, is proposed for use in microwave and millimetrewave circuits. It consists of a common resonator and an amplifier, compensating for losses in the resonator. Properly designed, such an arrangement behaves as a (passive) resonator with dramatically increased quality factor. High quality factors can be achieved even at millimetrewave frequencies, where common resonators suffer from losses due to small skin depths. Viability of the component is experimentally verified at microwave region using a TE01 dielectric resonator and an oscillator.
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    Dipole Array Excited by Slots in its Coaxial Feeder
    (Společnost pro radioelektronické inženýrství, 2001-12) Cernohorsky, D.; Novacek, Z.
    A technical analysis of the coaxial dipole-array excited by periodically distributed slots in common coaxial feeder is presented. The lossy transmission-line theory is applied for determination of the current on all parts of the system. Calculated results support some properties of the system, especially the radiation pattern and the input impedance.
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    Results of Indoor Propagation Measurement Campaign at 1900 MHz
    (Společnost pro radioelektronické inženýrství, 2001-12) Pechač, Pavel; Klepal, M.; Zvanovec, S.
    For the design of indoor picocellular systems in the frequency band of 1800/2100 MHz, a signal propagation modelling is needed. Empirical and semi-empirical models represent an efficient approach to the coverage prediction. For these models, suitable empirical parameters must be provided. The indoor propagation measurement campaign in the frequency range of 1900 MHz was carried out in several multi-floored buildings in Prague and Brno . For the campaign a special portable measurement system was developed. Based on the measurement results, the model parameters were derived. Optimised parameters are presented for two basic models (empirical and semi-empirical) according to the indoor environment classification. The results are compared to standard models as well. Accuracy and validity of derived models are discussed.