Josephson Junctions-Based Low-Temperature Superconducting Phase Shifter for X- and K-Bands Using MIT-LL SFQ5ee Process

This letter presents a low-temperature superconductor (LTS)-based
${X}$
- and
${K}$
-band analog ultra-wideband phase shifters realized by coupling an array of radio-frequency superconducting quantum interference devices (rf-SQUIDs) to a microwave transmission line (TL). The proposed device is realized using MIT-LL SFQ5ee eight-layer niobium-based process. The device is designed by distributing 2256 rf-SQUIDs coupled throughout the line exhibiting experimental analog current-controlled phase shift of 130° and insertion loss variation of 0.46 ± 0.23 dB in
${X}$
-band at
${f} _{c}$
= 10 GHz. In the
${K}$
-band, a phase shift of 328° and insertion loss of 2.5 ± 1 dB in
${K}$
-band at
${f} _{c}$
= 22.5 GHz is observed. Theoretical analysis of the phase shifter is discussed.