Tl/sub 2/Ba/sub 2/Ca/sub 1/Cu/sub 2/O/sub x/ thin films for microstrip filters

Abstract

High performance narrowband bandpass filters are required in satellite communication systems. Especially HTS filter banks are particularly attractive because of their low insertion loss and sharp filter skirts needed in input multiplexers. T1,Ba,CaCuZO, thin f i l m s on 2"-LaAlO,-substrates and 10xlOmmz-sapphire substrateswere prepared using a two s t e p technology. A TI-free precursor film is prepared by sputtering. The TI-incorporation is performed by annealing in a T1,O loaded atmosphere. The best films show surface resistances below 1OOp C2 at 77K and 4GHz. Two-pole bandpass-filters with a center frequency of 4GHz and a bandwidth o f 17.5MHz using dual-mode ring resonators have been fabricated from the films on LaA10,. The measured passband shape achieved with tuning elements is in good agreement with t h e specifications of the design.

Synthesis and microwave properties of TI2Ba2CaCu2O8 superconducting films grown by MOCVD

“…In respect to the potential application, Tl-2212 is characterized by greater ease of preparation, even if the optimum T c (110 K) is slightly lower, compared to Tl-2223 (T c = 125 K). Specifically, Tl-2212 presents a lower formation temperature which prevents chemical reaction with the substrate, resulting in better growth conditions on buffer layered substrates or in the case of double-sided films [2]. In this work we report on the a e-mail: pica@na.infn.it b Present address: I.N.F.M.…”

“…and Dipartimento di Scienze Fisiche, Universita' di Napoli Federico II, Napoli, Italy synthesis and microwave characterization of Tl-2212 films grown by a combined approach of metal-organic chemical vapor deposition (MOCVD) and thallium vapor diffusion. Tl-2212 films have been previously grown by a two step post-annealing process using laser ablation [3], magnetron [2] or off-axis sputtering [4,5]. MOCVD has the potential advantage of being a very reliable and reproducible technique for the fast production of films with a high degree of uniformity over large areas for both thickness and composition.…”

Fabrication and characterization of two-pole X-band HgBa2CaCu2O6+δ microstrip filters

“…[3][4][5][6] The much improved performance of these HTS microwave devices over their normalmetal counterparts has been attributed to the nearly an order of magnitude lower microwave surface resistance of HTS films, which can only be realized when the HTS devices are kept at liquid nitrogen temperature of 77 K much below their superconducting transition temperature T c . The increased interest was brought about by the perceived potential on the marketability of superconducting electronics especially in the wireless communications industry.…”

Dual mode cross slotted filter realized with double-sided Tl2Ba2CaCu2O8films grown by MOCVD

“…In particular, Tl-2212 presents a lower formation temperature which prevents chemical reaction with the substrate, resulting in better growth conditions. This is particularly significant for buffer layered substrates or in the case of double-sided films [2]. Several techniques with a two-step post-annealing process have been previously adopted, such as magnetron [2], laser ablation [3] or off-axis sputtering [4,5].…”

“…This is particularly significant for buffer layered substrates or in the case of double-sided films [2]. Several techniques with a two-step post-annealing process have been previously adopted, such as magnetron [2], laser ablation [3] or off-axis sputtering [4,5]. We have also previously reported on the realization of Tl-2212 single-sided films grown by a combined approach of metal-organic chemical vapour deposition (MOCVD) and thallium vapour diffusion [6].…”