Teraphysics Corporation completed the Phase I objectives for the electrical design of a 94 GHz, 26 W TWT with 53% overall efficiency, including the helical circuit with efficiency enhancing taper, input/output couplers, electron gun, magnetic circuit and multistage depressed collector. The device includes a novel, microfabricated, helical circuit with electron beam propagating above the helix rather than through the middle. In addition to completing all of the proposed Phase I objectives, we designed vacuum windows, made significant progress on the mechanical design, fabricated the electron gun electrodes and circuit block, and conducted machining trials, and brazing experiments. The successful Phase I results at 94 GHz along with Teraphysics' proven results at 95 and 650 GHz warrant further development of the 94 GHz TWT in a Phase II program. If awarded, we will apply our relevant experience and the Phase I results to fabricate, assemble, and test a 94 GHz TWT. The advantages of implementing high efficiency TWT amplifiers into NASA spacecraft compared to the current state of the art include lower system power requirements, reduced payload volume and reduced thermal management challenges.More »
The TWT is a vacuum device invented in the early 1940s for amplification of radio frequency (RF) power. Because of their high power, broad bandwidth, compact size, reliability and high efficiency, vacuum electron devices are used in several NASA applications including high data rate communications, radar, spectroscopy and remote sensing. Vacuum devices have a long history in NASA applications and are chosen for their unsurpassed efficiency, reliability, and power at high frequencies. They have been employed countless times by NASA in applications such as advanced cloud and precipitation radars, advanced SAR, radio science and telecommunications. In the area of telecommunications, this amplifier could enable very high data rate communications for links between orbiting satellites; planetary spacecraft; planetary surfaces and orbiting spacecraft; and deep space and earth. This 94 GHz technology would also increase the volume of data transmitted for low earth orbiting spacecraft that are in view of a ground station only briefly.
Military applications include high data rate, network-centric communications and anti-jam and low detection warfare communications; airborne, ship borne, and ground-based radar; jamming; and decoy applications. Commercial applications include satellite communications, radar, imaging, and materials processing. Teraphysics has the capability to commercially exploit this technology, and it would have a wealth of commercial opportunity. The upper end of the mm wavelength band will be attractive to space commercial users because of the large amounts of contiguous spectrum that are available for broadband, high data rate, satellite and wireless terrestrial communications. This is also applicable at E-Band where larger bandwidth is commercially available as well as around 140 GHz where there is more spectrum and fewer competing allocations. The technology developed for the proposed 94 GHz TWT can readily be applied at E-Band or operation above 100 GHz. In fact, the same 94 GHz slow wave circuit proposed here can operate at E-Band simply by increasing the beam voltage. Additional applications include imaging for areas such as homeland security.
|Organizations Performing Work
|Jet Propulsion Laboratory (JPL)