(a) 0.22 THz TWTA model (without sever ports). The inset shows half-period staggered TWT's single cell for dispersion analysis. (b) Dispersion curve showing 1st and 2nd pass-bands with spatial harmonics. Slow space charge wave beam line also drawn at the operating beam voltage 20 kV. (c) Gain versus frequency comparison from two PIC codes namely MAGIc3D and CST PIC.
(a) The conceptual drawing of the elliptic sheet beam in the traveling wave tube circuit. (b) TWTA RF assembly including two sections separated by sever ports. (c) Magnified image of the circuit part with input/output couplers and sever ports but without extended waveguides.
SEM image of the nano-machined TWTA slow wave structure (fabricated in three layers topology). The image on left shows the beam tunnel is integrated to the bottom plate. The image on right shows the mid plate.
(a) 0.22 THz TWTA under test employing WR5.1 frequency extenders (T/R modules) in the frequency range 140 GHz–228 GHz with the Agilent PNA-X network analyzer. (b) Two port S-parameters measurement plots for the long section of the 0.22 THz TWTA.
(a) The comparison of RF transmission/reflection measurements and simulation prediction for the 1st stage (short section) of the TWTA. (b) The same is repeated for the second stage (long section of the TWTA).
(a) 0.22 THz TWTA simulation model with input/output couplers and sever ports. (b) S-parameters for TWTA circuit for ideal conductivity (design). (c) S-parameters for the TWTA circuit with degraded conductivity to approximately imitate the cold test results. (d) Table shows the comparison of design and measured S-parameters with the results for degraded conductivity.
Beam-wave interaction analysis for the TWTA output performance for (a) Ideal S-parameters, (b) realistic S-parameters approximated with measured values using degraded conductivity. (c) and (d) Comparison of output power and Gain (dB) after 2nd section of TWTA versus frequency for (i) ideal S-parameters and (ii) realistic S-parameters.
Article metrics loading...
Full text loading...