The Laboratory of Quantum Cryogenic Electronics at Novosibirsk State Technical University has created a series of amplifiers capable of operating in conditions where temperature is measured in Kelvin units, and accuracy requirements go beyond traditional engineering practice. These devices are used in radio astronomy, space communication systems, quantum computing, and cryogenic electronics. The work was carried out within the framework of the Priority 2030 program.
"The laboratory team brings together specialists in the fields of microwave electronics, cryogenic physics, circuit engineering and numerical modeling. Their work is not a linear process from calculation to prototype, but a constant dialogue between experiment and theory. Every decision is tested in real conditions, and every result is rethought, refined, and brought to a state in which it can become part of a complex measurement system. In this sense, the amplifier is not just a product, but a recorded result of collective experience accumulating knowledge in related fields," says Alexey Vostretsov, Head of the laboratory, Professor of the Department of Design and Technology of Radioelectronic Devices at NSTU-NETI, Doctor of Technical Sciences.
The developed amplifiers provide high gain with minimal additional noise over wide frequency ranges. Their characteristics are formed not only by the choice of active elements (HEMT transistors with high electron mobility or SiGe structures), but also by the design methodology. The approach is based on the formation of target frequency dependences of impedances, at which the amplifier operates near the optimum in terms of noise and power transmission.
The practical significance of the developments has been confirmed experimentally in a number of Russian research laboratories. Amplifiers are already used in ultra-weak signal detection tasks, including quantum object reading systems and receiving paths with heterodyne conversion, which are used in almost all modern communication and radar systems. In these conditions, it is especially important to match the calculated and measured characteristics — this is where the value of the chosen design approach is shown.
One of the latest laboratory developments is a broadband amplifier in the 5 kHz — 500 MHz range. It is designed to operate at a temperature of 4 K, has a gain of more than 30 dB, and its noise temperature is less than 5 K, and its power consumption is less than 6 MW. Against the background of global solutions, the presented amplifiers demonstrate competitive parameters, combining low noise with moderate power consumption and flexible configurations. This opens up opportunities not only for scientific research, but also for applications where high sensitivity is required.
"Our team considers the creation of low-noise cryogenic amplifiers as a step in a broader process. Work is underway to further reduce noise temperature, expand operating ranges, and create integrated cryogenic microwave modules combining amplification, switching, and filtering. This approach allows us to move from individual components to complete solutions that form the architecture of future measurement systems," summarizes Alexey Vostretsov.