Quasi-optical slot antenna SIS mixers

A quasi-optical SIS mixer designed for efficient radiation coupling is described. The mixer uses a twin-slot antenna which has the advantages of a good beam pattern and a low impedance. The radiation and impedance characteristics of the antenna were obtained from a moment-matched calculation. Tapered superconducting microstrip transmission lines are used to carry the radiation from the slot antennas to the tunnel junction. The effective impedance seen by the tunnel junction is quite low, about 4 Omega , which allows micron-size junctions to be used at 500 GHz. The mixers have been fabricated using Nb/Al-oxide/Nb tunnel junctions and a receiver noise temperature of 420 K (DSB) was measured at 490 GHz, which is the best yet obtained for a quasi-optical mixer at this frequency. The comparatively large junction area increases the mixer saturation power and allows strong suppression of noise from the Josephson effect by the application of a magnetic field of modest strength. >

[1]  J. B. Beyer,et al.  A broad-band microwave superconducting thin-film transformer , 1988 .

[2]  Marc J. Feldman,et al.  Quantum detection at millimeter wavelengths , 1985 .

[3]  Emil Wolf,et al.  Principles of Optics: Contents , 1999 .

[4]  R. Miller,et al.  A 345GHz SIS receiver for radio astronomy , 1989 .

[5]  M. Feldman.  Theoretical considerations for THz SIS mixers , 1987 .

[6]  D. Schaubert,et al.  Dipole and slot elements and arrays on semi-infinite substrates , 1985 .

[7]  D. Smith,et al.  Optical constants of far infrared materials. 2: crystalline solids. , 1973, Applied optics.

[8]  C. P. McClay,et al.  Fabrication of Nb/Al-Al/sub 2/O/sub 3//Nb junctions with extremely low leakage currents , 1989 .

[9]  High quality Nb-AlO/sub x/-Nb junctions for microwave receivers and SFQ logic device , 1991 .

[10]  Thomas G. Phillips,et al.  A broad-band low-noise SIS receiver for submillimeter astronomy , 1988 .

[11]  T. Claeson,et al.  Quasiparticle mixing close to the gap frequency in aluminum tunnel junctions , 1985 .

[12]  Gerard Mourou,et al.  Propagation model for ultrafast signals on superconducting dispersive striplines , 1988 .

[13]  C. R. Brewitt-Taylor,et al.  Planar antennas on a dielectric surface , 1981 .

[14]  D. Mattis,et al.  Theory of the anomalous skin effect in normal and superconducting metals , 1958 .

[15]  P. Richards,et al.  SIS quasiparticle mixers with bow-tie antennas , 1988 .

[16]  Richard L. Kautz,et al.  Picosecond pulses on superconducting striplines , 1978 .

[17]  M. Wengler,et al.  Quantum noise in heterodyne detection , 1987 .

[18]  E. Hammerstad,et al.  Accurate Models for Microstrip Computer-Aided Design , 1980, 1980 IEEE MTT-S International Microwave symposium Digest.

[19]  L. R. D'Addario.  Saturation of the SIS mixer by out-of-band signals , 1988 .

[20]  P.H. Siegel,et al.  A Simple Quasi-Optical Mixer for 100-120 GHz , 1977, 1977 IEEE MTT-S International Microwave Symposium Digest.

[21]  W. Danchi,et al.  Frequency dependence of quasiparticle mixers , 1986 .

[22]  M. J. Wengler,et al.  85--115-GHz Receivers for Radio Astronomy , 1985 .

[23]  R. Poepel.  Electromagnetic Properties of Superconductors , 1989 .

[24]  Ely E. Bell,et al.  Measurement of the optical constants of crystal quartz in the far infrared with the asymmetric Fourier-transform method , 1967 .

[25]  P. Richards,et al.  Measurement of integrated tuning elements for SIS mixes with a Fourier transform spectrometer , 1988 .

[26]  J. Stern,et al.  All refractory NbN/MgO/NbN tunnel junctions , 1987 .

[27]  B. Syrett.  A broad-band element for microstrip bias or tuning circuits , 1980 .

[28]  T. Claeson,et al.  High-frequency limits of superconducting tunnel junction mixers , 1987 .

[29]  M. J. Wengler,et al.  A low noise receiver for millimeter and submillimeter wavelengths , 1985 .