Multipactor in Low Pressure Gas and in ... - of Richard Udiljak

(dBm)
(dBm)
−55
−60
−65
−70
−75
−80
−85
−90
−80
−100
−120
−140
Noise Power (32 − 52 s)
34 36 38 40 42
Time (s)
44 46 48 50 52
Fourier transform (32 − 52 s)
−160
0 50 100 150 200 250
frequency (Hz)
300 350 400 450 500
Figure 6.5: The beginning of a multipactor test sequence showing the time
before onset of the discharge. The FFT (fast Fourier transform)
gives no indication of dominant frequency components.
(dBm)
(dBm)
−55
−60
−65
−70
−75
−80
−85
−90
−80
−100
−120
−140
Noise Power (52 − 72 s)
54 56 58 60 62
Time (s)
64 66 68 70 72
Fourier transform (52 − 72 s)
−160
0 50 100 150 200 250
frequency (Hz)
300 350 400 450 500
Figure 6.6: The end of the same test sequence as in Fig. 6.5. The sudden increase
in the noise floor indicates onset of multipactor. The FFT
shows dominant frequency components at 100 Hz and multiples
thereof.
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