A novel multi-channel quadrature Doppler backward scattering reflectometer on the HL-2A tokamak.

A novel 16-channel fixed frequency Doppler backward scattering (DBS) reflectometer system has been developed on the HL-2A tokamak. This system is based on the filter-based feedback loop microwave source (FFLMS) technique, which has lower phase noise and lower power variation compared with present tunable frequency generation and comb frequency array generation techniques [J. C.

Development of microwave imaging reflectometry on the HL-2A tokamak.

A microwave imaging reflectometry system has been developed to visualize the density fluctuations on the HL-2A tokamak. This system is characterized by a quasi-optical system, a four frequency microwave transmitter, and a microwave quadrature receiver system with a 3D adjustable U-shaped horn antenna array, that generate 8 (poloidal) × 4 (radial) × 2 (toroidal) = 64 channel images of density fluctuations. Simulations and laboratory tests of the optical system have been conducted.