14-07-2012, 02:27 PM
MICROWAVE DEVICES
[attachment=27662]
MAGNETRON
A DIODE WHICH USES THE INTERACTION OF MAGNETIC AND ELECTRIC FIELDS IN A COMPLEX CAVITY TO PROVIDE OSCILLATIONS
10 MW – UHF; 2MW – X-BAND; 80 kW – 95 GHz
EFFICIENCY OF 50-60%
SEMICONDUCTOR MICROWAVE DEVICES
TRANSISTOR
2-4 GHz, 9W, 12-8 dB
29.5-32.5 dB at 4-6 GHz, 15 mW
FET – G=10dB, 9-15 GHz, F=7-14 dB
PARAMETRIC AMPLIFIER
USES A DEVICE WHOSE REACTANCE VARIES SUCH THAT AMPLIFICATION RESULTS
WAVEGUIDE
A HOLLOW METALLIC TUBE USED TO PROPAGATE SIGNALS TYPICALLY FROM 3-100 GHz BAND
TRANSMITS MULTIPLE SIGNAL OVER THE SAME FREQUENCY BUT IN DIFFERENT MODES
PROBLEMS
WHAT WILL BE THE CUT-OFF WAVELENGTH FOR THE DOMINANT MODE IN RECTANGULAR WAVEGUIDE WHOSE BREADTH IS 10 cm? FOR A 2.5 GHz SIGNAL PROPAGATED IN THIS GUIDE IN THE DOMINANT MODE, CALCULATE THE GUIDE WAVELENGTH, THE GROUP AND PHASE VELOCITIES AND THE CHARACTERISTIC WAVE IMPEDANCE?
[attachment=27662]
MAGNETRON
A DIODE WHICH USES THE INTERACTION OF MAGNETIC AND ELECTRIC FIELDS IN A COMPLEX CAVITY TO PROVIDE OSCILLATIONS
10 MW – UHF; 2MW – X-BAND; 80 kW – 95 GHz
EFFICIENCY OF 50-60%
SEMICONDUCTOR MICROWAVE DEVICES
TRANSISTOR
2-4 GHz, 9W, 12-8 dB
29.5-32.5 dB at 4-6 GHz, 15 mW
FET – G=10dB, 9-15 GHz, F=7-14 dB
PARAMETRIC AMPLIFIER
USES A DEVICE WHOSE REACTANCE VARIES SUCH THAT AMPLIFICATION RESULTS
WAVEGUIDE
A HOLLOW METALLIC TUBE USED TO PROPAGATE SIGNALS TYPICALLY FROM 3-100 GHz BAND
TRANSMITS MULTIPLE SIGNAL OVER THE SAME FREQUENCY BUT IN DIFFERENT MODES
PROBLEMS
WHAT WILL BE THE CUT-OFF WAVELENGTH FOR THE DOMINANT MODE IN RECTANGULAR WAVEGUIDE WHOSE BREADTH IS 10 cm? FOR A 2.5 GHz SIGNAL PROPAGATED IN THIS GUIDE IN THE DOMINANT MODE, CALCULATE THE GUIDE WAVELENGTH, THE GROUP AND PHASE VELOCITIES AND THE CHARACTERISTIC WAVE IMPEDANCE?