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The new concept of symmetric (double-folded) and asymmetric (single-folded) folded meander-line slow-wave structures is proposed for broader bandwidth and higher interaction impedance characteristics, respectively. The structures are analyzed using 3D numerical simulation in CST-Microwave Studio for the dispersion and interaction impedance characteristics at Ka- and W-bands. The results are compared...
L-3 Communications Electron Technologies Inc., (L-3 ETI), continues to push the envelope for spacedownlink qualified mm-wave helix TWTs. We report results of high-power, wide bandwidth, and extreme environmental margin testing on the mm-wave family of helix TWTs from 22 GHz to 75 GHz.
A 220 GHz power amplifier has been demonstrated as part of the DARPA HiFIVE program. This amplifier is based on a folded waveguide circuit, and operates at 19 kV and 250 mA. Short pulse tests resulted in 56 W at 214 GHz and a 5.0 GHz bandwidth.
A CW 48 GHz 500 Watt saturated 250 MHz Extended Interaction Klystron (EIK) has been developed and delivered for use in the ESA Alphasat program. Designed for integration into a new CPI Satcom Division High Power Amplifier (HPA), this EIK may be operated in a linear mode up to 300 Watts rated output power, with performance optimized at 75 Watts. The EIK is temperature stabilized over a 60°C temperature...
A high-order-mode harmonic multiplying gyro-TWA could allow the amplifier to achieve high average powers. An improved mode-selective circuit is employed for suppressing non-TE0n competing modes while wall losses are employed for suppressing TE0n competing modes. A G-band second harmonic multiplying gyro-TWT is predicted to yield a peak output power of 56 kW at 200 GHz with an efficiency of 11%, a...
The analysis of the lossy interaction structure for Ka-band Gyro-TWT has been carried out and discussed. In this paper, dispersion and interaction impedance characteristics of the interaction structure have been determined using 3-D simulator CST-MWS. The beam-wave interaction analysis has been carried out using particle-in-cell (PIC) code MAGIC. The simulated result shows that the interaction structure...
In this paper, the design and optimization of a V-band helix TWT is carried out and prototype tubes have been assembled. The test results show that the output power of the TWT is over 15W with the overall efficiency of over 14.5% and a gain of over 43dB. The beam transmission experiment shows that a transmission ratio is over 97%.
The experimental study of a Q-band gyrotron-travelling-wave tube (gyro-TWT) amplifier operating in the circular TE01 mode at fundamental cyclotron harmonic is presented. A periodic dielectric loaded structure is adopted in the interaction circuit of the gyro-TWT to suppress spurious modes TE11 and TE21. A saturated peak power of 175 kW is obtained corresponding to saturated gain of 53 dB and an efficiency...
This paper presents the development of W-band folded waveguide pulsed TWT. We have obtained experimentally over 100W output power with 5GHz instantaneous bandwidth and 33dB gain at 20% duty cycle.
A 0.850 THz vacuum electronic power amplifier capable of >50 mW output power is being tested at Northrop Grumman Electronic Systems. The compact power amplifier is based on a DRIE-fabricated folded waveguide slow-wave circuit, together with a high current density thermionic cathode, a high field permanent magnet solenoid, and a single-stage depressed collector for overall device efficiency. The...
A gyrotron amplifier that uses a novel photonic band gap (PBG) interaction circuit has achieved a peak small signal gain of 38 dB at 247.7 GHz, 32 kV and 0.35 A. The instantaneous −3 dB bandwidth of the amplifier at peak gain is 0.4 GHz. A peak output power of 45 W has been measured. The output power is not saturated but is limited by the 7.5 mW of available input power; the saturated output power...
A novel slow-wave-structure (SWS) named angular log-periodic micro-strip meander-line was proposed in this paper. This kind of slow wave structure is mainly determined by 3 parameters only, and the calculation results show that it has a very weakly dispersion s. That is to say, its operation bandwidth would be very wide. Its another advantage is the low operation voltage. The radial normalized phase...
We present the hot test results of a 220 GHz, serpentine waveguide vacuum electron amplifier showcasing a novel embedded monofilament microfabrication technique based on UV-LIGA. The instantaneous operating bandwidth exceeds 15 GHz and the small signal gain of the circuit is over 14 dB. By varying the voltage slightly, an operating bandwidth of almost 40 GHz is realizable with a minimum circuit gain...
A modified slotted helix slow-wave structure is proposed to develop high-power, wide-bandwidth millimeter TWT. The electromagnetic characteristics are calculated by HFSS. The results show that the modified structure has higher interaction impedance and lower attenuation compared with original slotted helix SWS, which would lead to higher output power in millimeter-wave TWT.
A two stage ‘driver-booster’ TWT configuration designed to produce 1.8 kW in Ka-band will be described. The folded waveguide circuit used in the power booster is designed to meet bandwidth requirements while simultaneously eliminating the usual stop-band at 2π, in order to avoid drive-induced oscillation.∗
A Ku-Band high power Gyro-TWT is designed and the experiment hot test has been finished. The operating mode is TE11 mode. A linear polarized input coupler is used to introduce the input power. The start-oscillation current of operating TE11 mode and the backward TE21 mode is studied by the linear, non-linear self-consistent theory and 3D PIC simulation. The loss ceramics are used in the HF circuit...
Launched in December 2010 KA-SAT represents the first of the current generation of High Throughput Satellites (HTS). With a total system capacity of over 90Gbit/s and the capability of supporting up to a million users, it delivers services akin to those provided by terrestrial ADSL2+. In order to meet increasing demands on capacity, and subsequently on equipment, it is expected that the bandwidth...
L-3 EDD has developed a W-Band TWT with 100 W RF power over 4 GHz of bandwidth around 94 GHz suitable for MPM integration. The TWT employs an aperture grid modulated electron gun with mod-anode current control, a serpentine waveguide interaction circuit, and a single-stage depressed collector. Two TWTs have been built and tested to over 100 W pulsed output power. The first unit has been operated at...
Selex ES has a well consolidated heritage in design and production of conventional traveling wave tubes and helix mini-TWT for military naval, airborne and missile applications. Strong on his own experience Selex ES is developing a wideband, 100 Watts CW, helix mini-TWT to satisfy the increasing demand of systems capable of high power level over wide operating bandwidth; the main application being...
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