A hybrid phase shifter circuit based on TlCaBaCuO superconducting thin films
- Univ. of Cincinnati, OH (United States)
- NASA Lewis Research Center, Cleveland, OH (United States)
A superconductor-semiconductor hybrid reflection type phase shifter circuit has been designed, fabricated, an characterized for 180 {degree} phase bit with center frequency of GHz and bandwidth of 0.5 GHz for operation at 77 K. Al of the passive components of the phase shifter circuit such a input/output feed lines, 3 dB Lange coupler, impedance marching networks, and transmission lines consisted of thallium based superconducting TlCaBaCuO thin films of 4,000 {angstrom} thickness on lanthanum aluminate substrate. Metal-Schottky field-effect-transistors (MESFET`s) on GaAs semiconductor were used as active devices for switching action (on-state and off-state) in the phase shifter circuit. The phase shift and insertion losses were investigated as a function of frequency from 3.6 to 4.6 GHz at 77 K. The circuit exhibited a fairly flat response of 180{degree} phase shift with a maximum deviation of less than 2{degree} and a maximum insertion loss of 2 dB for on-state and 2.2 dB for off-state conditions over 0.5 GHz bandwidth at 4 GHz. The insertion losses were also fairly flat within the bandwidth. The insertion losses were constant between 50 and 80 K, giving the circuit a large range of operation at or below 77 K. The performance of this circuit as compared to a gold microstrip-semiconductor circuit designed identically was superior by a factor of 1.5, and may be due to lower conductor losses and lower surface resistance in the superconducting microstrips.
- OSTI ID:
- 46096
- Journal Information:
- IEEE Transactions on Microwave Theory and Techniques, Vol. 43, Issue 3; Other Information: PBD: Mar 1995
- Country of Publication:
- United States
- Language:
- English
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