Robust and Reliable Receivers for the ITER ECE System

The US role in ITER is focused on the key diagnostic instruments, such as the Electron Cyclotron Emission (ECE) Radiometer. Present concepts for this instrument require a compact and reliable receiver that yields instantaneous coverage of the 200-300GHz frequency range. Presently available millimeter-wave receivers are unable to meet this requirement. Virginia Diodes proposes a system of three state-of-the-art heterodyne receivers, each of which will cover one-third of the desired ITER band. The input waveguides of these receivers will be combined into a single guide using an innovative waveguide triplexer. A quasi-optical system will couple the triplexer to the ITER system. The most important innovations in the project are VDIs efforts to fundamentally improve the performance and reliability of the receivers. These include a new fabrication technology for the diode integrated circuits and methods to improve the IF bandwidth of the mixers. VDI successfully demonstrated the proposed IC fabrication technology, demonstrated the IF bandwidth required for the ITER receivers while increasing also reliability, and conducted an initial reliability study of the receiver technology. The basic technology for the waveguide triplexer was also demonstrated. The Phase 2 plan culminates in the demonstration and delivery of a functional receiver system for the ITER ECE Radiometer system. Primary research areas include; the development of a highly integrated receiver architecture using both the new diode integrated circuit technology and the integration of many circuit functions into the same housing, the development of the new waveguide triplexer, the development and evaluation of the three receiver systems, the demonstration of the complete ITER system, and a thorough study of reliability of all system components and sub-systems. Commercial Applications and Other Benefits: Terahertz technology is an emerging field with a broad array of scientific, military, medical and commercial applications. The development of broader band and more reliable receivers is a primary requirement for the continued growth of this field.