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Development of Submillimeter SIS Mixers and Broadband HEMT Amplifiers

Jonas Stasys Zmuidzinas

Published Oct 5, 2004• 0 citations
OpenAlex

Abstract

The goal of this project is to develop and demonstrate a new generation of superconducting tunnel junction (SIS) receivers with extremely wide instantaneous (intermediate-frequency, or IF) bandwidths, of order 12 GHz. Such mixers would allow rapid submillimeter wavelength spectral line surveys to be carried out with SOFIA, and could potentially be used for future submillimeter space missions such as SAFIR. There are two major components which are being developed: (1) SIS mixers with broad (12 GHz) IF bandwidths; and (2) low-noise, broadband microwave, (6-18 GHz) amplifiers, which amplify the IF output from the SIS mixer. The work on these components is discussed in two sections

Related papers

Submillimeter receiver components using superconducting tunnel junctions

Michael J. Wengler, A. Pance, B. Liu +3 more

Superconducting tunnel diodes (SISs) are investigated for both the generation and detection of submillimeter wavelengths. For detection, heterodyne receivers using SISs are investigated. Josephson currents are found to have a large effect on SIS mixers in the submillimeter, even though their effect is less at lower frequencies. At 492 GHz, fixer conversion gain increased by 4 dB when Josephson currents are not suppressed by a magnetic field. A much higher noise is seen in this gain mode, but further investigation of this recently discovered phenomenon is warranted. For submillimeter generation, a two-dimensional array of SISs is investigated. The ac Josephson effect in the SIS is expected to deliver submillimeter power into a free-space radiation mode traveling perpendicular to the array. No experimental devices have been developed yet, but the authors show computer simulations and microwave scale model measurements of array structures.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jul 1, 1991•0 citations

A millimeter unilateral finline SIS mixer with a wide IF bandwidth

Yangjun Zhou

Superconductor-Insulator-Superconductor (SIS) tunnel junction mixers are now commonly used in as- tronomical receivers at (sub)millimeter wavelengths because of their superb sensitivity, high dynamic range and stability of operation. Niobium SIS mixers operating at frequencies well below the super- conducting gap (∼680 GHz) have already achieved quantum limited sensitivity. Therefore to further enhance the receiver sensitivity, increasing the Intermediate Frequency (IF) bandwidth of SIS mixers has became crucial. This thesis focuses on the theoretical modeling, design and experimental verifi- cation of Nb SIS mixers operating around 230 GHz with a wide IF bandwidth of 1–15 GHz. These mixers were designed for a single baseline heterodyne interferometer (GUBBINS), which is being built to observe the Sunyaev-Zel’dovich effect in the Cosmic Microwave Background. The combination of wide IF bandwidth SIS mixers and complex analogue correlators will allow GUBBINS to feature high surface brightness sensitivity, that helps to distinguish the weak SZ effect from the background noise. The SIS mixer detector system was assembled inside the GUBBINS cryostat together with the IF electronics and RF/LO optical systems. Low noise temperatures of around 71 K were then measured in the GUBBINS system. The Nb SIS mixer we have developed uses a unilateral finline and fully integrated planar circuits deposited on a silicon substrate, to couple the electromagnetic radiation from the waveguide into the SIS junction. The finline mixer allows a broad-band RF coupling, an easy integration of the on-chip planar circuits and an easy-to-fabricate mixer block. To achieve a wide IF bandwidth, the output impedance of the SIS mixer was well matched to the input impedance of the amplifier by a multi-stage microstrip circuit. Additionally, the planar circuit of the SIS mixer was also designed to have a small lumped inductance and capacitance. The SIS mixer chip was extensively simulated by rigorous electromagnetic software (HFSS) and the S-parameter was exported to a quantum mixing package SuperMix to produce a full-wave model of the mixer. Experimental testing yielded a best noise temperature of 50 K with an average noise temperature of 75 K over an RF bandwidth of 160 GHz– 260 GHz. We have performed thorough experimental and computational investigation of the IF system in particular the constraints on the bandwidth caused by the lumped element capacitance of the mixer chip and the matching of the output impedance of the mixer to the IF amplifier. Our conclusion is that a bandwidth of 1–15 GHz could be achieved using our mixer design, subject to the performance of the amplifier. Finally, a variable temperature load system was successfully developed and tested inside the cryostat, to avoid the losses from the room-temperature optics. We have showed that the noise temperature of the SIS detector could be reduced by as much as 15 K by testing the mixer using a variable temperature load inside the cryostat.

•Jan 1, 2013•0 citations

A Very Wide Bandwidth SIS Heterodyne Receiver Design for Millimeter and Submillimeter Astronomy

F. Rice

This text describes in some detail the design and operational history of an instrument used as the front-end receiver for a fast, broadband, high-resolution spectrometer for the 1.3 millimeter wavelength atmospheric window. Using only a single superconductor-insulator-superconductor (SIS) tunnel junction as its heterodyne detector, the receiver’s novel design achieved then unprecedented RF and IF bandwidths and incorporated several innovations which have since been widely adopted within the millimeter and submillimeter wave research communities. Although intended as a relatively simple technology demonstrator and starting point for more refined and sophisticated designs, the receiver turned out to be a useful astronomical instrument in its own right, and it was deployed as a de facto facility instrument for several years at the Caltech Submillimeter Observatory. Also described are the author’s contributions to another important aid to research and design efforts: the SuperMix software library for the analysis and optimization of high-frequency circuitry, especially developed to aid in the design of systems involving SIS and other superconducting elements. Finally, the text may serve as a useful introduction to the theory behind and methodology for modeling and design of SIS heterodyne mixers.

•Sep 18, 2020•0 citations

Towards Ultimate Performance of THz Heterodyne Receivers: SIS Frequency Multiplier and Wideband Passive Components

Hawal Rashid

This thesis focuses on the development of advanced components for the future wideband side band separating and / or multipixel receivers for radio-astronomy with ultimate sensitivity.\nIn this thesis, a novel frequency multiplier based on distributed superconducting tunnel (SIS) junctions has been demonstrated for the first time, taking advantage of the extreme inherent nonlinearity of such device. This practical demonstration is the result of an extensive theoretical exploration and modelling, showing the importance of the reactive quasi-particle tunnel current\nand its impact on the SIS tunnel junction frequency multiplier. In addition, a novel technique\nwas suggested that allows for the first time direct measurement of the reactive quasi-particle tunnel current.\nThis work comprehends the analysis, design and characterisation of the first frequency multiplier using distributed SIS junctions. The measured output power generated by the distributed SIS junction at the second harmonic of the input frequency were in good agreement\nwith the model. Furthermore, the distributed SIS junction as a frequency multiplier were for the first time able to pump an SIS mixer. An efficiency of the distributed SIS junction multiplier of 15-30 % for a fractional bandwidth of 10% with excellent spectral line purity were\ndemonstrated. The -3 dB line width of the multiplied signal is better than 1 Hz, which were the lowest resolution bandwidth of the spectrum analyser. Consequently, the results attained in this work show that the distributed SIS junction frequency multiplier has considerable future potential, and could possibly be used in LO source in single-ended and multi-pixel SIS mixer\nlayouts.\nFurthermore, in order to improve the sideband rejection ratio of cryogenically cooled sideband separating receivers for radio astronomy receivers to more than 15 dB over a wide RF and IF bandwidth, novel wideband RF and IF hybrid couplers have been developed and demonstrated\nwith very low imbalances. More specifically, a 4-8 GHz IF assembly comprising a compact 90° hybrid chip, two bias-T circuits and two transmission line circuits was designed and characterised. The compact size of the hybrid chip allows it to be integrated into virtually any sideband separating (2SB) mixer operating at cryogenic temperatures and is furthermore especially advantageous for multi-pixel 2SB receivers or low noise balanced amplifier layouts.\nThe characterisation of the hybrid assembly was performed at a cryogenic temperature of 4 K and sophisticated calibration and fixture de-embedding procedures were used. To further improve the sideband rejection ratio, a novel design for a RF 90° waveguide hybrid with very\nlow amplitude imbalance over a fractional bandwidth of 30% (159-216 GHz) was demonstrated. Both Hybrids are currently implemented in the ALMA Band 5 receivers, which\nrepresent the state-of-the-art for ultra-low noise sideband separated receivers.\nIn order to allow complete characterisation of the ALMA Band 5 cartridge a highly versatile measurement setup has been built. The measurement setup includes all necessary hardware and achieves automatic measurements for the system noise and sideband rejection with in-built\noptimisation procedures. The measurement setup additionally comprises measurements of the receiver saturation, phase and amplitude stability, as well as optical beam characterisation.

•Jan 1, 2016•0 citations

Submillimeter mixers based on superconductive parallel junction arrays

Faouzi M. Boussaha, Morvan C. Salez, Y. Delorme +4 more

Observation and analysis of submillimeter-wave radiation (300GHz-3THz) in astronomy and atmospheric sciences requires increasingly performant receivers. The most sensitive receivers working in this range of electromagnetic spectrum use superconductor-insolator-superconductor (SIS) junctions. In order to increase the bandwidth and the sensitivity, we are developing a quantum-noise limited heterodyne receiver based on several parallel SIS junctions with broad (larger than 30%) fixed tuned bandwidth. These circuits can be viewed as passband filters which have been optimized by varying the spacings between junctions. We have designed such 5-junction arrays for operation in the range 480-640 GHz. Fabrication and heterodyne characterization of these devices has been done. The 1 μm2 junctions current density ranges from 4 to 13 kA/cm2, using optical lithography and Nb/Al2Nb5/Nb trilayer sputtering technology. The fabrication process and yield are presented in this paper, along with measured performances

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 25, 2003•1 citation

Ultra-wide IF bandwidth — The next frontier for SIS receivers

Edward Tong, Paul Grimes, Jonathan Weintroub +1 more

Tucker's theory of quantum mixing can be extended to model distributed series connected SIS mixers, which offer a lower capacitance and a higher dynamic range. These mixers have wider IF bandwidth than single junction mixer. Coupled with the emerging ultra-wide band technologies in low noise amplifier and fast digital signal processing, they open a new frontier of ultra-wide band receivers. We report on the development of the wideband SIS receivers for the Submillimeter Array, designed with Tucker's theory.

IEEE MTT-S International Microwave Symposium digest•May 1, 2015•2 citations
The goal of this project is to develop and demonstrate a new generation of superconducting tunnel junction (SIS) receivers with extremely wide instantaneous (intermediate-frequency, or IF) bandwidths, of order 12 GHz. Such mixers would allow rapid submillimeter wavelength spectral line surveys to be carried out with SOFIA, and could potentially be used for future submillimeter space missions such as SAFIR. There are two major components which are being developed: (1) SIS mixers with broad (12 GHz) IF bandwidths; and (2) low-noise, broadband microwave, (6-18 GHz) amplifiers, which amplify the IF output from the SIS mixer. The work on these components is discussed in two sections
Superconducting tunnel diodes (SISs) are investigated for both the generation and detection of submillimeter wavelengths. For detection, heterodyne receivers using SISs are investigated. Josephson currents are found to have a large effect on SIS mixers in the submillimeter, even though their effect is less at lower frequencies. At 492 GHz, fixer conversion gain increased by 4 dB when Josephson currents are not suppressed by a magnetic field. A much higher noise is seen in this gain mode, but further investigation of this recently discovered phenomenon is warranted. For submillimeter generation, a two-dimensional array of SISs is investigated. The ac Josephson effect in the SIS is expected to deliver submillimeter power into a free-space radiation mode traveling perpendicular to the array. No experimental devices have been developed yet, but the authors show computer simulations and microwave scale model measurements of array structures.
Superconductor-Insulator-Superconductor (SIS) tunnel junction mixers are now commonly used in as- tronomical receivers at (sub)millimeter wavelengths because of their superb sensitivity, high dynamic range and stability of operation. Niobium SIS mixers operating at frequencies well below the super- conducting gap (∼680 GHz) have already achieved quantum limited sensitivity. Therefore to further enhance the receiver sensitivity, increasing the Intermediate Frequency (IF) bandwidth of SIS mixers has became crucial. This thesis focuses on the theoretical modeling, design and experimental verifi- cation of Nb SIS mixers operating around 230 GHz with a wide IF bandwidth of 1–15 GHz. These mixers were designed for a single baseline heterodyne interferometer (GUBBINS), which is being built to observe the Sunyaev-Zel’dovich effect in the Cosmic Microwave Background. The combination of wide IF bandwidth SIS mixers and complex analogue correlators will allow GUBBINS to feature high surface brightness sensitivity, that helps to distinguish the weak SZ effect from the background noise. The SIS mixer detector system was assembled inside the GUBBINS cryostat together with the IF electronics and RF/LO optical systems. Low noise temperatures of around 71 K were then measured in the GUBBINS system. The Nb SIS mixer we have developed uses a unilateral finline and fully integrated planar circuits deposited on a silicon substrate, to couple the electromagnetic radiation from the waveguide into the SIS junction. The finline mixer allows a broad-band RF coupling, an easy integration of the on-chip planar circuits and an easy-to-fabricate mixer block. To achieve a wide IF bandwidth, the output impedance of the SIS mixer was well matched to the input impedance of the amplifier by a multi-stage microstrip circuit. Additionally, the planar circuit of the SIS mixer was also designed to have a small lumped inductance and capacitance. The SIS mixer chip was extensively simulated by rigorous electromagnetic software (HFSS) and the S-parameter was exported to a quantum mixing package SuperMix to produce a full-wave model of the mixer. Experimental testing yielded a best noise temperature of 50 K with an average noise temperature of 75 K over an RF bandwidth of 160 GHz– 260 GHz. We have performed thorough experimental and computational investigation of the IF system in particular the constraints on the bandwidth caused by the lumped element capacitance of the mixer chip and the matching of the output impedance of the mixer to the IF amplifier. Our conclusion is that a bandwidth of 1–15 GHz could be achieved using our mixer design, subject to the performance of the amplifier. Finally, a variable temperature load system was successfully developed and tested inside the cryostat, to avoid the losses from the room-temperature optics. We have showed that the noise temperature of the SIS detector could be reduced by as much as 15 K by testing the mixer using a variable temperature load inside the cryostat.
This text describes in some detail the design and operational history of an instrument used as the front-end receiver for a fast, broadband, high-resolution spectrometer for the 1.3 millimeter wavelength atmospheric window. Using only a single superconductor-insulator-superconductor (SIS) tunnel junction as its heterodyne detector, the receiver’s novel design achieved then unprecedented RF and IF bandwidths and incorporated several innovations which have since been widely adopted within the millimeter and submillimeter wave research communities. Although intended as a relatively simple technology demonstrator and starting point for more refined and sophisticated designs, the receiver turned out to be a useful astronomical instrument in its own right, and it was deployed as a de facto facility instrument for several years at the Caltech Submillimeter Observatory. Also described are the author’s contributions to another important aid to research and design efforts: the SuperMix software library for the analysis and optimization of high-frequency circuitry, especially developed to aid in the design of systems involving SIS and other superconducting elements. Finally, the text may serve as a useful introduction to the theory behind and methodology for modeling and design of SIS heterodyne mixers.
This thesis focuses on the development of advanced components for the future wideband side band separating and / or multipixel receivers for radio-astronomy with ultimate sensitivity.\nIn this thesis, a novel frequency multiplier based on distributed superconducting tunnel (SIS) junctions has been demonstrated for the first time, taking advantage of the extreme inherent nonlinearity of such device. This practical demonstration is the result of an extensive theoretical exploration and modelling, showing the importance of the reactive quasi-particle tunnel current\nand its impact on the SIS tunnel junction frequency multiplier. In addition, a novel technique\nwas suggested that allows for the first time direct measurement of the reactive quasi-particle tunnel current.\nThis work comprehends the analysis, design and characterisation of the first frequency multiplier using distributed SIS junctions. The measured output power generated by the distributed SIS junction at the second harmonic of the input frequency were in good agreement\nwith the model. Furthermore, the distributed SIS junction as a frequency multiplier were for the first time able to pump an SIS mixer. An efficiency of the distributed SIS junction multiplier of 15-30 % for a fractional bandwidth of 10% with excellent spectral line purity were\ndemonstrated. The -3 dB line width of the multiplied signal is better than 1 Hz, which were the lowest resolution bandwidth of the spectrum analyser. Consequently, the results attained in this work show that the distributed SIS junction frequency multiplier has considerable future potential, and could possibly be used in LO source in single-ended and multi-pixel SIS mixer\nlayouts.\nFurthermore, in order to improve the sideband rejection ratio of cryogenically cooled sideband separating receivers for radio astronomy receivers to more than 15 dB over a wide RF and IF bandwidth, novel wideband RF and IF hybrid couplers have been developed and demonstrated\nwith very low imbalances. More specifically, a 4-8 GHz IF assembly comprising a compact 90° hybrid chip, two bias-T circuits and two transmission line circuits was designed and characterised. The compact size of the hybrid chip allows it to be integrated into virtually any sideband separating (2SB) mixer operating at cryogenic temperatures and is furthermore especially advantageous for multi-pixel 2SB receivers or low noise balanced amplifier layouts.\nThe characterisation of the hybrid assembly was performed at a cryogenic temperature of 4 K and sophisticated calibration and fixture de-embedding procedures were used. To further improve the sideband rejection ratio, a novel design for a RF 90° waveguide hybrid with very\nlow amplitude imbalance over a fractional bandwidth of 30% (159-216 GHz) was demonstrated. Both Hybrids are currently implemented in the ALMA Band 5 receivers, which\nrepresent the state-of-the-art for ultra-low noise sideband separated receivers.\nIn order to allow complete characterisation of the ALMA Band 5 cartridge a highly versatile measurement setup has been built. The measurement setup includes all necessary hardware and achieves automatic measurements for the system noise and sideband rejection with in-built\noptimisation procedures. The measurement setup additionally comprises measurements of the receiver saturation, phase and amplitude stability, as well as optical beam characterisation.
Observation and analysis of submillimeter-wave radiation (300GHz-3THz) in astronomy and atmospheric sciences requires increasingly performant receivers. The most sensitive receivers working in this range of electromagnetic spectrum use superconductor-insolator-superconductor (SIS) junctions. In order to increase the bandwidth and the sensitivity, we are developing a quantum-noise limited heterodyne receiver based on several parallel SIS junctions with broad (larger than 30%) fixed tuned bandwidth. These circuits can be viewed as passband filters which have been optimized by varying the spacings between junctions. We have designed such 5-junction arrays for operation in the range 480-640 GHz. Fabrication and heterodyne characterization of these devices has been done. The 1 μm2 junctions current density ranges from 4 to 13 kA/cm2, using optical lithography and Nb/Al2Nb5/Nb trilayer sputtering technology. The fabrication process and yield are presented in this paper, along with measured performances
Tucker's theory of quantum mixing can be extended to model distributed series connected SIS mixers, which offer a lower capacitance and a higher dynamic range. These mixers have wider IF bandwidth than single junction mixer. Coupled with the emerging ultra-wide band technologies in low noise amplifier and fast digital signal processing, they open a new frontier of ultra-wide band receivers. We report on the development of the wideband SIS receivers for the Submillimeter Array, designed with Tucker's theory.