Voltage tuneable phase shift in coplanar waveguides based on HTSC / ferroelectric thin film structures was investigated. The transmission lines were fabricated from YBa_2Cu_3O_(7-δ)/ Ba_xSr_(1-x)TiO_3 double layers deposited on 5 * 5 mm~2 LaAlO_3 substrates. It was shown that a significant improvement of the tuneability can be achieved by proper choice of the ferroelectric material and the waveguide dimensions. As ferroelectric the solid solution Ba_xSr_(1-x)TiO_3 with x = 0.05 was chosen because its Curie temperature is close to 77 K. The epitaxial growth of both layers was confirmed by X-Ray Diffraction. Phase shift of 254° tuned by 35 V dc bias was demonstrated at 20 GHz and 75 K.
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机译：研究了基于HTSC /铁电薄膜结构的共面波导的电压可调相移。沉积在5×5mm〜2 Laalo_3基板上的YBA_2CU_3O_（7-Δ）/ BA_XSR_（1-x）TiO_3双层制造传输线。 It was shown that a significant improvement of the tuneability can be achieved by proper choice of the ferroelectric material and the waveguide dimensions.作为铁电，选择具有X = 0.05的固溶体Ba_XSR_（1-X）TiO_3，因为其居里温度接近77k。通过X射线衍射证实两层的外延生长。在20GHz和75k中对35 V DC偏置进行了254°的相移。
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