High Temperature Superconducting Ferrite Phase Shifter with New Latching Structure

Superconductor ferrite phase shifters are attractive
for phased array radar systems. The huge reduction in size and
losses mean that smaller systems are possible. This paper reports
a new latching structure for a superconducting ferrite phase
shifter which is compact in size and has low losses. The total size
of the phase shifter is 6.0 cm x 3.0 cm x 2.5 cm including
housing. It should be pointed out that two phase shifters can be
accommodated in this size. The minimum insertion loss of the
designed phase shifter was measured at 0.8 dB. The phase shifter
is fabricated using a Yttrium Barium Copper Oxide (YBCO)
microstrip meander-line on a one centimeter square low loss
sapphire substrate. We press contacted a magnetized ferrite
substrate, with a silver ground plane, onto the fabricated YBCO
meander-line to obtain non-reciprocal phase shifting. To
magnetize the ferrite substrate without causing magnetic field
penetration into the high temperature superconductor (HTS), we
propose a new latching structure comprising a single ferrite
layer with magnetizing coils. This new structure will confine the
magnetic field within the ferrite substrate by providing a closed
magnetic path. This is achieved by making a large hole at center
of the ferrite substrate.

Citation:
Yeo, K. S. K and Lancaster, M. J. (2001) "High Temperature Superconducting Ferrite Phase Shifter with New Latching Structure", IEEE Trans. Applied Superconductivity, 11 (1) 430-433.