RF Power Measurements Using Quantum Interference in Superconductors | NIST

A novel design of a radio-frequency (RF) power limiter for protecting sensitive superconductor receiver components from high-power microwave signals is presented. In this approach, two low- ${T} _{c}$ superconductor microstrip lines, one of which is coupled with an array of RF superconducting quantum interference devices (rf-SQUIDs), are combined with a pair of hybrid couplers to provide the power limiting operation at very low RF power levels. The key concept is built on the fact that a microstrip line coupled to an array of rf-SQUIDs behaves as a power-dependent phase shifter and its phase can be controlled by the input RF power. This phenomenon is exploited to achieve the desired RF power-limiting operation. The device is fabricated using an eight-layer niobium-based superconducting process node SFQ5ee by MIT Lincoln Laboratory (MIT-LL). A monolithically integrated wideband hybrid coupler is used in this design as it dictates the bandwidth of the overall device. The operating frequency of the power limiter is 10 GHz with a 2-GHz bandwidth. The performance of the device is measured for input RF power levels ranging from −30 to +10 dBm, as well as arising intermodulation products are experimentally investigated. The output power increases linearly with the input power up to −15 dBm, and for higher power levels, the device offers an increasing attenuation to limit the output RF power starting above −15 dBm.A novel design of a radio-frequency (RF) power limiter for protecting sensitive superconductor receiver components from high-power microwave signals is presented. In this approach, two low-${T} _{c}$superconductor microstrip lines, one of which is coupled with an array of RF superconducting quantum interference devices (rf-SQUIDs), are combined with a pair of hybrid couplers to provide the power limiting operation at very low RF power levels. The key concept is built on the fact that a microstrip line coupled to an array of rf-SQUIDs behaves as a power-dependent phase shifter and its phase can be controlled by the input RF power. This phenomenon is exploited to achieve the desired RF power-limiting operation. The device is fabricated using an eight-layer niobium-based superconducting process node SFQ5ee by MIT Lincoln Laboratory (MIT-LL). A monolithically integrated wideband hybrid coupler is used in this design as it dictates the bandwidth of the overall device. The operating frequency of the power limiter is 10 GHz with a 2-GHz bandwidth. The performance of the device is measured for input RF power levels ranging from −30 to +10 dBm, as well as arising intermodulation products are experimentally investigated. The output power increases linearly with the input power up to −15 dBm, and for higher power levels, the device offers an increasing attenuation to limit the output RF power starting above −15 dBm.

IEEE Transactions on Microwave Theory and TechniquesDec 1, 202210 citations

Instrumentation using quantum interference in superconductors

James Edward Zimmerman

Aug 16, 19651 citation

Static and radio frequency magnetic response of high T c superconducting quantum interference filters made by ion irradiation

Eliana Recoba Pawlowski, Julien Kermorvant, Denis Crété +7 more

Abstract Superconducting quantum interference filters (SQIF) are promising devices for radio frequency (RF) detection combining low noise, high sensitivity, large dynamic range and wide-band capabilities. Impressive progress has been made recently in the field, with SQIF based antennas and amplifiers showing interesting properties in the GHz range using the well-established Nb/AlO x technology. The possibility to extend these results to high temperature superconductors (HTS) is still open, and different techniques to fabricate HTS SQIFs compete to make RF devices. We report on the DC and RF response of a high temperature SQIF fabricated by the ion irradiation technique. It is made up of 1000 superconducting quantum interference devices in series, with loop areas randomly distributed between 6 and 60 μ m 2 . The DC transfer factor is ∼450 V T −1 at optimal bias and temperature, and the maximum voltage swing ∼2.5 mV. We show that such a SQIF detects RF signals up to 150 MHz. It presents linear characteristics for RF power spanning more than five decades, and non-linearities develop beyond P RF = −35 dBm in our set-up configuration. The second harmonic generation has been shown to be at a minimum at the functioning point in the whole range of frequencies. A model has been developed which captures the essential features of the SQIF RF response.Abstract Superconducting quantum interference filters (SQIF) are promising devices for radio frequency (RF) detection combining low noise, high sensitivity, large dynamic range and wide-band capabilities. Impressive progress has been made recently in the field, with SQIF based antennas and amplifiers showing interesting properties in the GHz range using the well-established Nb/AlO x technology. The possibility to extend these results to high temperature superconductors (HTS) is still open, and different techniques to fabricate HTS SQIFs compete to make RF devices. We report on the DC and RF response of a high temperature SQIF fabricated by the ion irradiation technique. It is made up of 1000 superconducting quantum interference devices in series, with loop areas randomly distributed between 6 and 60 μ m 2 . The DC transfer factor is ∼450 V T −1 at optimal bias and temperature, and the maximum voltage swing ∼2.5 mV. We show that such a SQIF detects RF signals up to 150 MHz. It presents linear characteristics for RF power spanning more than five decades, and non-linearities develop beyond P RF = −35 dBm in our set-up configuration. The second harmonic generation has been shown to be at a minimum at the functioning point in the whole range of frequencies. A model has been developed which captures the essential features of the SQIF RF response.

arXiv:1802.10310Superconductor Science and TechnologyJul 10, 201817 citations

A novel design of a radio-frequency (RF) power limiter for protecting sensitive superconductor receiver components from high-power microwave signals is presented. In this approach, two low-

{T} _{c}

superconductor microstrip lines, one of which is coupled with an array of RF superconducting quantum interference devices (rf-SQUIDs), are combined with a pair of hybrid couplers to provide the power limiting operation at very low RF power levels. The key concept is built on the fact that a microstrip line coupled to an array of rf-SQUIDs behaves as a power-dependent phase shifter and its phase can be controlled by the input RF power. This phenomenon is exploited to achieve the desired RF power-limiting operation. The device is fabricated using an eight-layer niobium-based superconducting process node SFQ5ee by MIT Lincoln Laboratory (MIT-LL). A monolithically integrated wideband hybrid coupler is used in this design as it dictates the bandwidth of the overall device. The operating frequency of the power limiter is 10 GHz with a 2-GHz bandwidth. The performance of the device is measured for input RF power levels ranging from −30 to +10 dBm, as well as arising intermodulation products are experimentally investigated. The output power increases linearly with the input power up to −15 dBm, and for higher power levels, the device offers an increasing attenuation to limit the output RF power starting above −15 dBm.