J. Phys. IV France 08 (1998) Pr3-171-Pr3-174
A cryogenic GaAs PHEMT/ferroelectric Ku-band tunable oscillatorR.R. Romanofsky1, F.W. Van Keuls2 and F.A. Miranda1
1 National Aeronautics and Space Administration, Lewis Research Center, Cleveland, Ohio 44135, U.S.A.
2 National Research Council, NASA Research Associate at Lewis Research Center
A Ku-band tunable oscillator operated at and below 77 K is described. The oscillator is based on two separate technologies : a 0.25 µm GaAs pseudomorphic high electron mobility transistor (PHEMT) circuit optimized for cryogenic operation, and a gold micostrip ring resonator patterned on a thin ferroelectric (SrTiO3) film which was laser ablated onto a LaAlO3 substrate. A tuning range of up to 3% of the center frequency was achieved by applying dcbias between the ring resonator and ground plane. To the best of our knowledge, this is the first tunable oscillator based on a thin film ferroelectric structure demonstrated in the microwave frequency range. The design methodology of the oscillator and the performance characteristics of the tunable resonator are described.
© EDP Sciences 1998