As a part of plan to deploy a wideband high-power module (HPM) to very high-throughput satellite (VHTS) network systems, CPI has been developing a V-band high-power TWT amplifier. The first two prototypes designed for 500 W and 250 W levels of saturated output power were fully tested, showing 24 dB gain and more than 5 GHz bandwidth with 50 - 100 % of duty factor. Currently, a 3 rd prototype is being developed with the plan to release its version compatible with market-demands. This paper will summarize their fabrication processes and test results.

Return Loss in a Helix TWT output circuit vs. frequency is both physically measured and modeled using 3D RF simulation software. The modeled RF circuit extends from helix sever to output waveguide. Comparison of both sets of data show strongly correlated results both in phase and magnitude over a broad frequency range.

Communication and Power Industries (CPI), USA has designed, and developed a novel 1,250 Watt high power, high efficiency, compact, conduction-cooled continuous wave Helix Traveling Wave tube VTU6397J4 for Satcom application. This paper presents the test results of the two initial TWT prototypes produced. Both units were tested in a light-weight conduction-cooled baseplate, used SMA female coaxial input and WR-75 waveguide output connections as designed. Both prototypes measured over 1,300 watts of average CW output power, over 51 dB of small signal gain across the extended Ku-band from 12.75GHz through 14.80 GHz. TWT's demonstrated good linearity and third-order intermodulation performances at 4 dB and 7 dB back-offs from rated power (61.0 dBm). TWT design includes a standard proven electron Gun assembly with FE turn-on and isolated anode, a two stage multi-stage depressed collector assembly, and a novel slow wave structure. Test results are in agreement with the design goals. The predicted and measured performance data are compared.

We describe a design for a coaxial inductive output tube (IOT) that operates in the 200 MHz range with 250 kW CW output power. Of particular interest are formation of a radial beam with a cylindrical gridded gun, and high efficiency RF interaction in a coaxial output cavity.