Summary form only given. In modern pulsed radar and amplitude modulation reflectometry of fusion plasma the high speed PIN switches and PIN attenuators are used. They provide the amplitude modulation to several hundred MHz and pulses with a pulse duration of 1-3 ns. The resolution in the measurement of the distances to the plasma strongly depend on the speed of the modulators. An ultrafast varactor amplitude modulator has been designed for the use in pulsed radar and AM reflectometry over the millimeter band. The modulator provides the speed of the amplitude modulation of 5 GHz and pulses of 0.2 ns with ON/OFF ratio of 25-30 dB for a single diode and 35-40 dB for the two diode modulator. Insertion losses are 1.5-2 dB. It can operates with a source which has an output in the CW mode to a few watts. The modulator has a narrow frequency band <1 GHz, but in reflectometers which use sources working at fixed frequencies it is not regarded as a disadvantage, because each source can be supplied with an individual modulator. The modulator provides a linear change of the output signal with change of the bias voltage from zero to 15 V and can be used as an electrical tuning attenuator.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Ultrafast millimeter wave amplitude modulator for reflectometry of plasma


    Contributors:
    Ermak, G.P. (author)


    Publication date :

    1996-01-01


    Size :

    64698 byte




    Type of media :

    Conference paper


    Type of material :

    Electronic Resource


    Language :

    English



    Ultrafast Millimeter Wave Amplitude Modulator for Reflectometry of Plasma

    Ermak, G. P. | British Library Conference Proceedings | 1996


    Millimeter-wave beam shaping using phased antenna arrays for imaging plasma reflectometry

    Liang, Y. / Chang, C.-C. / Domier, C.W. et al. | IEEE | 2004


    Novel Millimeter-wave Electro-optic Modulator

    Bridges, W.B. / Sheehy, F.T. / Schaffner, J.H. | IEEE | 1990



    Microwave Reflectometry Based On Amplitude Modulation

    Ling, B.L. / Sh.Fei, Q. / Ti, A. et al. | IEEE | 2006