A low-noise double-dipole antenna SIS mixer at 1 THz

Abstract

A quasi-optical mixer employing a Nb/Al/AlO x /Nb twin-SIS junction with a NbTiN/SiO 2 /Al microstrip coupling circuit is tested at 800-1000 GHz. The mixer design is developed as an option for HIFI frequency bands 3 and 4. The double-dipole antenna is made from NbTiN/Al; a Nb film is used for the back reflector. The mixer design is optimized for the IF band of 4-8 GHz. The receiver noise temperature T RX = 250 K (DSB) is measured at 935 GHz for the bath temperature 2 K at IF=1.5 GHz; T RX remains below 350 K within the frequency range 850-1000 GHz. The double-dipole antenna beam pattern demonstrated good symmetry with sidelobes below -16 dB. IntroductionLow-noise THz-band heterodyne receivers are needed to realize the full potential of airborne and space-based telescopes currently being developed for sub-millimeter spectral astronomy, e. g. for HIFI [1]. To consider the possibility of designing an effective SIS mixer at 1 THz, it is worth to have a brief look at the most critical parameters of SIS mixers.

Superconducting detectors and mixers for millimeter and submillimeter astrophysics

“…However, above 700 GHz, tuning inductors made with the most commonly used superconductor (niobium) become lossy [225] because photons have enough energy to break Cooper pairs , and the mixer performance degrades rapidly. Various approaches have been used to mitigate this problem [226], including the use of normal [190], [220], [222], [227], [231], [232], [234], [235], [237], [238], [276]- [284]. The HEB data are from [236], [285]- [296].…”

“…The HEB data are from [236], [285]- [296]. metal circuits [227], [228], higher gap superconductors such as NbN or NbTiN [229]- [237], and very high current density AlN-barrier junctions [221], [233], [238], [239]. At present, SIS mixers have been successfully operated at frequencies up to 1.25 THz-the latest result for the Herschel/HIFI 1.2-THz SIS mixer is 530 K (DSB) uncorrected, and below 400 K after correction for the LO beamsplitter [280].…”

Enhancement of terahertz coupling efficiency by improved antenna design in GaN/AlGaN high electron mobility transistor detectors

“…It has been reported that there are possibilities of low production costs and excellent performance in THz detection, such as tunability, [6−11] operating at room temperature [12] and a relatively low value of the noise equivalent power. [13−15] In order to improve the performance of THz detectors, a great deal of attention has focused on the development of THz antennas for applications in THz detection technology, such as bowtie antenna, [16] rectangular microstrip patch antenna, [17] and other types of antennas. [18] Recently, Panasonic Corporation reported a resonant detection in a nanogate high electron mobility transistor.…”

Low Noise 1 THz–1.4 THz Mixers Using Nb/Al-AlN/NbTiN SIS Junctions

“…The quantum assisted tunneling in SIS junctions is vanishing at about double gap frequency. The commonly used Nb/AlOx/Nb junctions have the gap voltage about 2.8 mV allowing building sensitive receivers up to the frequency of about 1.1 THz [3], [4]. The introduction of the new type of high quality Manuscript Nb/AlN/NbTiN junctions with the gap voltage of about 3.5 mV made our work possible [5].…”