Summary form only given. The author has surveyed the current state of the art of superconductive electronics. Emphasis was placed on circuits employing low-temperature superconducting materials such as lead (critical temperature T/sub c/=7 K) and two refractory materials, niobium (T/sub c/=9 K) and niobium nitride (T/sub c/=16 K). Efforts have been made to integrate these devices with a multilithic antenna on a 1-cm silicon chip to form a superconductive monolithic integrated 100-GHz heterodyne receiver. The goal of this effort was to develop a fully superconductive phased-array receiver. The author has also examined the status of further research in Josephson junction technology and phased-locked arrays of these junctions.>
Summary form only given. The author has surveyed the current state of the art of superconductive electronics. Emphasis was placed on circuits employing low-temperature superconducting materials such as lead (critical temperature T/sub c/=7 K) and two refractory materials, niobium (T/sub c/=9 K) and niobium nitride (T/sub c/=16 K). Efforts have been made to integrate these devices with a multilithic antenna on a 1-cm silicon chip to form a superconductive monolithic integrated 100-GHz heterodyne receiver. The goal of this effort was to develop a fully superconductive phased-array receiver. The author has also examined the status of further research in Josephson junction technology and phased-locked arrays of these junctions.>
Refractive superconducting materials such as niobium (T/sub c/=9 K) and niobium nitride (T/sub c/=16 K) are used in the development of electronic devices for use at millimeter and submillimeter wavelengths. The author describes this program, and discusses the inherent advantages of superconductive electronics and the potential of the high-temperature materials for communication systems. The work concentrates on three areas: (1) the development of the components of a phased-array receiver operating in the 0.1-to-0.3 THz frequency regime; (2) research into NbN Josephson junction (JJ) technology and JJ arrays to provide the basic building blocks for a similar development in the THz regime; and (3) the development of analog and digital signal processing devices using superconducting technology.>
Abstract Superconductor electronics combines passive and active superconducting components and sometimes normal resistors into functional circuits and systems that also include room-temperature electronics for amplification, power sources, necessary controls, etc., usually computer operated. Furthermore, complete systems include magnetic and electromagnetic shielding, cryogenic enclosures, and increasingly a cryocooler in self-contained units. Components or devices of low or high critical temperature superconductors include inductances (coils), passive transmission lines, resonators, antennae, filters, as well as active elements: Josephson junctions, Josephson oscillators, and superconducting quantum interference devices. Of multiple demonstrated applications, mostly but not only in science and metrology, currently most successful are voltage standards, astronomy detectors and large telescope cameras, instruments for material characterization, and magnetometers for geomagnetic prospecting. Major current efforts concentrate on energy-efficient high-end computing and quantum computing. The outcomes of these efforts are likely to be known in the course of the following decade.
The concept of a fully superconducting integrated receiver is developed and experimentally tested. This single-chip sub-mm wave receiver includes a planar antenna integrated with a SIS mixer and an internal superconducting Josephson-type local oscillator (flux-flow oscillator, FFO). The receiver is tested with a DSB noise temperature below 100 K around 500 GHz being pumped by its internal local oscillator (LO). The instantaneous bandwidth of 15-20% is estimated via FTS and heterodyne measurements that meet the requirements of most practical applications. The far field antenna beam is measured as ≈ f /10 with sidelobes below -16 dB that is suitable for coupling to a real telescope antenna. A nine-pixel imaging array receiver with each pixel containing an internally pumped receiver chip is developed and tested. A linewidth of the phase locked FFO as low as 1 Hz is measured relative to a reference oscillator in the frequency range 270-440 GHz. An rf amplifier on the base of a dc SQUID is developed and tested showing a noise figure below 10 K at 4 GHz and a bandwidth of about 300 MHz. This amplifier can be included as a part of an integrated receiver that is valuable for array applications.
High temperature superconducting Josephson arrays were investigated as possible millimeter wave sources. A junction technology was selected and improved to the point where radiation, near 1 microwatt off-chip, was measured from a variety of 2-dimensional arrays in the 70-160 GHz range. The arrays were tunable and were successfully coupled to a number of antennas for broadband, tunable transmission. Antennas for a variety of specific applications were selected on the basis of bandwidth requirements, impedance levels, polarization, and the possibility of sufficient monolithic integration. The final part of the program was a study of potential subsystems that would utilize these arrays. Interchip communications transceivers were studied and interchip coupling was demonstrated using two antenna-coupled arrays. The most promising application may be a monolithic clock source, near 100 GHz, for communications and signal processing systems.
The CSIRO Applied Superconductivity Group has a long-term effort in research and development of superconducting electronic devices and systems for various practical applications. In this paper, I will mainly describe our recent research progress in developing novel HTS Josephson devices for high frequency applications. Specifically, we have recently developed a novel HTS Josephson heterodyne gigahertz (GHz) microwave oscillator and on-chip down-converter (mixer). For even higher frequency application, we developed a HTS Josephson junction terahertz (THz) detector and applied it successfully to THz imaging. I will highlight some of the recent results and describe the on-going effort of developing an array of such detectors and associated electronics as well as system integration.
High temperature superconducting Josephson arrays were investigated as possible millimeter wave sources. A junction technology was selected and improved to the point where radiation, near 1 microwatt off-chip, was measured from a variety of 2-dimensional arrays in the 70-160 GHz range. The arrays were tunable and were successfully coupled to a number of antennas for broadband, tunable transmission. Antennas for a variety of specific applications were selected on the basis of bandwidth requirements, impedance levels, polarization, and the possibility of sufficient monolithic integration. The final part of the program was a study of potential subsystems that would utilize these arrays. Interchip communications transceivers were studied and interchip coupling was demonstrated using two antenna-coupled arrays. The most promising application may be a monolithic clock source, near 100 GHz, for communications and signal processing systems. Josephson arrays, mm-wave sources.