Quasi-Optical Slot Antenna SIS Mixers

The 2nd International Symposium on Space Terahertz Technology

Jonas Zrnuidzinas

Others  :  http://www.nrao.edu/meetings/isstt/papers/1991/1991481490.pdf
PID  :  27892

来源: CEUR

【 摘 要 】

The slot-antenna mixer is a new quasi-optical SIS mixer design which attempts to simultaneously solve the antenna pattern and impedance-matching problems to obtain highly efficient radiation coupling. The mixers have been fabricated by the authors at JPL's Microdevices Laboratory (MDL). The devices employ robust Nb/Al-oxide/Nb tunnel junctions, and have been tested at Caltech. A receiver noise temperature of 420 K (DSB) was measured at 500 GHz, which is the best yet reported for an SIS or Schottky mixer at this frequency. The design of this mixer is readily scalable to 1000 GHz with current fabrication capabilities. The design allows reasonable junction areas to be used, even at high frequencies, which can easily be fabricated using the NbiAl-Oxicleil sTh and NbN/IvIg0/114bN processes. For example, an 800 Gliz mixer requires a single junction with an area of about 0.5μm² . The larger junction areas alleviate the effects of mixer saturation and allow strong suppression of the noise from the Josephson effect by the application of a magnetic field. The slot-antenna mixer should have a reasonable bandwidth, about 1.6:1, which would allow the 500-1000 6Hz band to be covered with only 2-3 devices.