2013/4

Browse

Recent Submissions

Now showing 1 - 5 of 42
  • Thumbnail Image
    Item
    The Design of Polymer Planar Optical Triplexer with MMI Filter and Directional Coupler
    (Společnost pro radioelektronické inženýrství, 2013-12) Jerabek, Vitezslav; Busek, Karel; Prajzler, Vaclav; Mares, David; Svoboda, Rudolf
    Optical bidirectional WDM transceiver is a key component of the Passive Optical Network of the Fiber to the Home topology. Essential parts of such transceivers are filters that combine multiplexing and demultiplexing function of optical signal (triplexing filters). In this paper we report about a design of a new planar optical multi-wavelength selective system triplexing filter, which combines a multimode interference filter with directional coupler based on the epoxy polymer SU-8 on Si/SiO2 substrate. The optical triplexing filter was designed using the Beam Propagation Method. The aim of this project was to optimize the triplexing filter optical parameters and to minimize the planar optical wavelength selective system dimensions. The multimode interference filter was used for separation of downstream optical signal in designed optoelectronic integrated WDM transceiver. The directional coupler was used for adding of upstream optical signal.
  • Thumbnail Image
    Item
    IR Thermometer with Automatic Emissivity Correction
    (Společnost pro radioelektronické inženýrství, 2013-12) Dobesch, Ales; Poliak, Juraj
    The paper describes the design and implementation of an infrared (IR) thermometer with automatic emissivity correction. The temperature measurement is carried out by the simple digital thermopile sensor MLX90614. The emissivity correction is based on benefits of diffuse reflecting materials and it uses an IR laser diode in conjunction with a selective amplifier. Moreover, the paper includes the design of the control interface with a graphics LCD. Furthermore, this paper describes the power supply unit with a Li-ion cell controlled by basic integrated circuits.
  • Thumbnail Image
    Item
    Closed-Form Approximation for Parallel-Plate Waveguide Coefficients
    (Společnost pro radioelektronické inženýrství, 2013-12) Valtr, Pavel; Pechac, Pavel
    Simple closed-form formulas for calculating coefficients of modes excited in a parallel-plate waveguide illuminated by a planar wave are presented. The mode-matching technique and Green’s formula are used to arrive at a matrix-based expression for waveguide coefficients calculation. Simplified solution to this matrix is proposed to derive approximate mode coefficient formulas in closed-form for both TE and TM polarization. The results are validated by numerical simulations and show good accuracy for all incidence angles and in broad frequency range.
  • Thumbnail Image
    Item
    Temperature and Frequency Dependent Empirical Models of Dielectric Properties of Sunflower and Olive Oil
    (Společnost pro radioelektronické inženýrství, 2013-12) Vrba, Jan; Vrba, David
    In this article, a known concept and measurement probe geometry for the estimation of the dielectric properties of oils have been adapted. The new probe enables the~measurement in the frequency range of 1 to 3000 MHz. Additionally, the measurement probe has been equipped with a~heat exchanger, which has enabled us to measure the dielectric properties of sunflower and olive oil as well as of two commercial emulsion concentrates. Subsequently, corresponding linear empirical temperature and frequency dependent models of the dielectric properties of the above mentioned oils and concentrates have been created. The dielectric properties measured here as well as the values obtained based on the empirical models created here match the data published in professional literature very well.
  • Thumbnail Image
    Item
    Prague's Emission Fourier Transform Microwave Spectrometer - Design and Preliminary Results
    (Společnost pro radioelektronické inženýrství, 2013-12) Kabourek, Vaclav; Cerny, Petr; Piksa, Petr; Studecky, Tomas; Kania, Patrik; Urban, Stepan
    The design, performance and operation of the high resolution microwave spectrometer are described. The spectrometer is based on the Fabry-Perot resonator supplemented by a pulsed supersonic nozzle for adiabatic cooling of the sample. The spectrometer’s high sensitivity and resolution are demonstrated by several examples.