共查询到20条相似文献,搜索用时 78 毫秒
1.
Nuss M.C. Goossen K.W. Mankiewich P.M. Howard R.E. Straughn B.L. Berkstresser G.W. Brandle C.D. 《Electron Device Letters, IEEE》1990,11(5):200-202
The surface resistance of high-quality YBa2Cu3 O7 superconducting films measured over a frequency range from 10 to 500 GHz using high-speed optoelectronic techniques is discussed. A direct comparison is made with the surface resistance of gold and superconducting niobium conductors. Using the measured surface resistance, the propagation characteristic of interconnects based on YBa 2Cu3O7 superconductors at 77 K is simulated and compared to that of gold transmission lines at 77 K and superconducting niobium lines at 7.7 K 相似文献
2.
We describe how coplanar microwave resonators fabricated from patterned thin films of YBa2Cu3O7(-δ) (YBCO) can he used to measure the ab-plane microwave surface impedance Zs=Rs+jXs of the films, in particular the absolute value and temperature dependence of the magnetic penetration depth λ. The current distribution of the resonator is calculated by modelling the resonator as a network of coupled transmission lines of rectangular cross-sections; this is then used to estimate the ab-plane λ(T) from the measurements of resonators of different geometries patterned onto the same film. We obtain values of λ(0) in the range 150-220 nm. The unloaded quality factors of the linear resonators at 7.95 GHz are around 45000 at 15 K and around 6500 at 77 K. We estimate the corresponding values of the intrinsic Rs at 7.95 GHz to be 23 μΩ and 110 μΩ at 15 K and 77 K, respectively. These values are comparable with those of other high quality unpatterned YBCO films reported in the literature. Zs for the best optimised films appears to be insensitive to the effects of patterning 相似文献
3.
Chorey C.M. Kong K.-S. Bhasin K.B. Warner J.D. Itoh T. 《Microwave Theory and Techniques》1991,39(9):1480-1487
Superconducting microstrip ring resonators operating at 35 GHz have been fabricated from laser ablated YBa2Cu3O 7-x (YBCO) films on lanthanum aluminate substrates. The circuits consisted of superconducting strips over normal metal ground planes. The circuits are measured from 20 K to 90 K and with microwave input powers ranging from 0.25 mW to 10 mW. The superconducting resonators show significant improvement in Q over identical gold resonators at 20 K, but only marginal improvement at 77 K. No variation in the superconductor performance is observed with varying input power. The lowest microwave surface resistance of the superconductors at 77 K is 9 mΩ. The change in the resonant frequency with temperature is analyzed and a value for the penetration depth computed. Double resonances were observed in some superconducting ring resonators and an explanation is advanced. Factors limiting millimeter-wave high-temperature superconductor circuits are explored and potential performance levels calculated based on current reported values for high-temperature superconductor surface resistances 相似文献
4.
Schmidt M.S. Forse R.J. Hammond R.B. Eddy M.M. Olson W.L. 《Microwave Theory and Techniques》1991,39(9):1475-1479
Results on three types of passive microwave devices fabricated and tested using epitaxial thin films of Tl2CaBa2Cu 2O8 grown on LaAlO3 are reported. A microstrip ring resonator with unloaded Q of 2740 at 77 K and 33 GHz is described. A superconducting 4.6 GHz band-reject filter with unloaded Q greater than 15000 when operated at 77 K is reported. In addition, results on a multiple microstrip bandpass filter are presented 相似文献
5.
Berntgen J. Waffenschmidt E. Musolf J. Xiaoyin He Heuken M. Heime K. Hofschen S. Wolff I. 《Microwave Theory and Techniques》1996,44(2):318-325
The microwave properties of coplanar waveguides with line widths from 1 μm to 40 μm made of superconducting YBaCuO films with a thickness t=180 nm on LaAlO3 are investigated. The line impedance ZL and the normalized propagation coefficient β/β0 of these waveguides are measured between 45 MHz and 26.5 GHz at temperatures between 77.4 K and 92 K. The ratio of the line width w to the distance of the ground layers d is constant with w/d=0.2. Therefore, ZL and β/β0 are independent of w for perfectly conducting waveguides. For superconducting waveguides it is found that ZL and β/β0 differ from the values of perfectly conducting waveguides. They increase for smaller line widths at a constant temperature. At w=1 μm and T=80 K, ZL and β/β 0 are nearly twice as high as calculated for perfect conductors. Furthermore, ZL and β/β0 increase with the temperature. It is shown that these effects are attributed to an increase of the inductance per unit length L' due to the superconducting material, whereas the capacitance per unit length C' behaves like C' of perfectly conducting waveguides. Using these results, the dimensions of the superconducting waveguides, which are necessary to obtain a desired ZL at a given line width w, are calculated 相似文献
6.
Microwave surface resistance measurements have been made on large-area Ti-Ba-Ca-Cu-O thick films magnetron-sputtered onto oriented Ag alloy substrates by replacing the end wall of an 18 GHz TE011 mode Cu cavity with the superconducting film. The best surface resistance values obtained are 4 and 14 mΩ at 10 K and 77 K, respectively; corresponding Cu values are 8 and 21 mΩ. The dependence of the surface resistance on microwave power was measured in a similar way except that a Nb cavity was used instead of a Cu cavity. Typically, the surface resistance of the film begins to rise in 1-10 Oe of microwave field and saturates in 20-60 Oe. A model is presented relating the observed saturation to critical penetration of Josephson junctions. Films exhibiting the highest degree of c -axis texturing show the weakest dependence of surface resistance on power and also exhibit the sharpest transition to the superconducting state as measured at high frequency 相似文献
7.
Misra M. Kataria N.D. Pinto R. Tonouchi M. Srivastava P. 《Applied Superconductivity, IEEE Transactions on》2001,11(4):4128-4135
The microwave surface resistance, Rs measurement of YBa 2Cu307 -δ (YBCO) thin film deposited on 10 mm × 10 mm LaAlO3 substrate using three prime resonating techniques, namely, cavity end plate substitution technique (20 GHz), dielectric resonator technique (18 GHz), and microstrip resonator technique (5 GHz), is reported. In addition, theoretical analysis for each technique has been performed to calculate the relative percentage error in the measured Rs -value of the YBCO thin film as a function of temperature. It has been found that the shielded dielectric resonator provides far better sensitivity for R.-measurement of the YBCO thin film with minimum relative percentage error (<4%) in the temperature range from 20 K to transition temperature of YBCO thin film compared to the other two techniques 相似文献
8.
Liang G.C. Withers R.S. Cole B.F. Garrison S.M. Johansson M.E. Ruby W.S. Lyons W.G. 《Applied Superconductivity, IEEE Transactions on》1993,3(3):3037-3042
The very low microwave surface resistance of high-temperature-superconductor (HTS) thin films allows the realization of microwave devices with performance superior to those made by conventional technology. Superconducting delay lines, for example, have very low propagation loss and dispersion. Long, low-loss, superconducting delay lines on both thinned LaAlO3 and sapphire substrates are presented. Delay lines with 27- and 44-ns delay have been made, for the first time, on 5-cm-diameter 254- and 127-μm-thick LaAlO3 substrates, respectively. The insertion losses at 77 K and 6 GHz are 6 and 16 dB, respectively. Delay lines with 9-ns delay have, for the first time, been produced on M-plane sapphire substrates and demonstrate, at 77 K, an insertion loss of 1.0 dB at 6 GHz. A 2.5%-bandwidth 10 GHz four pole edge-coupled bandpass filter on M-plane sapphire substrates is also reported. The filter has minimum insertion loss of less than 0.5 dB at 9.75 GHz and 71 K 相似文献
9.
Tellmann N. Glein N. Dahne U. Scholen A. Schulz H. Chaloupka H. 《Applied Superconductivity, IEEE Transactions on》1994,4(3):143-148
We have investigated a dielectric resonator consisting of a single crystalline LaAlO3-cylinder shielded by a cylindrically shaped copper cavity with endplates made from epitaxial films of YBa2Cu3O7 or niobium. For YBa2 Cu3O7 films unloaded quality factors Q0 of 4.5·105 at 10 K and 1.3·105 at 77 K were achieved at 11.6 GHz using a compact shielding cavity with a diameter of 15 mm and a height of 3.8 mm. The loss contributions of the dielectric resonator, the normal conducting cylinder wall, and the superconducting endplates, with one of them being separated by a small distance h from the dielectric cylinder, were calculated by modeling the electromagnetic fields of the TE0νμ-modes. The dielectric loss tangent of the LaAlO 3-cylinders was found to be 10-6 at 4.3 K and f=11.6 GHz and to increase slightly with temperature. Moreover, the calculations indicate the tunability of the resonance frequency by changing h over a range of 1 GHz without significant degradation of Q 0. These resonators are considered to be useful devices for stable oscillators and narrowband filters 相似文献
10.
Ng G.I. Hong W.-P. Pavlidis D. Tutt M. Bhattacharya P.K. 《Electron Device Letters, IEEE》1988,9(9):439-441
The DC and microwave performance of a strained In0.65Ga0.35As/In0 .52A10.48As HEMT (high-electron-mobility transistors) is reported. Its design is based on theoretical and experimental studies including low- and high-field transport characterization of heterostructures with different strains. The intrinsic DC transconductance and cutoff frequence of 1.4-μm-long gate HEMTs are 574 mS/mm and 38.6 GHz, respectively. The increased indium (In) composition in the channel enhances the drift velocity from 1.35×107 to 1.55×107 cm/s at 300 K 相似文献
11.
Namordi M.R. Mogro-Campero A. Turner L.G. Hogue D.W. 《Microwave Theory and Techniques》1991,39(9):1468-1474
A 50-Ω coplanar waveguide (CPW) resonator designed for a fundamental frequency of about 4.75 GHz was fabricated on LaAlO3 . Two versions were fabricated: the first using 1.9-μm-thick gold and the second using 0.6-μm-thick YBa2Cu3O 7. The devices were identically packaged and tested at 77 K. It was found that the high-temperature superconductor (HTS) resonator had a surface resistance, R s, about six to nine times lower than the Au one. At 45 K, the R s of the HTS resonator decreases by another factor of 4 compared with its 77 K value. Device characteristics for the HTS resonator are presented 相似文献
12.
Analysis and experimental results are presented for a parallel-plate dielectric resonator method to measure the surface resistance of conducting or superconducting plates. In the present paper, three main questions are considered in detail: the influence of the relative sizes of the conducting or superconducting plates on the measured value of the surface resistance Rs; the influence of the shape of the plates on the Rs measurement; and how to interpret obtained results. Measurements were made at resonant frequencies of 14.1-14.5 GHz in a temperature range between 77 and 300 K 相似文献
13.
The microwave effective surface impedances of different stacks made of YBa2Cu3O7 films, dielectric materials, and bulk normal metals were computed, using the two-fluid model of superconductors and conventional transmission line theory. these effective impedances are compared to the calculated intrinsic surface impedances of the stacked superconducting films with a penetration depth of 220 nm and a normal resistivity of 100 μΩ-cm at 77 K. The films were assumed to be epitaxial, with thicknesses ranging from a few nanometers to 1 μm. The discrepancy between the effective surface resistances or reactances and the corresponding intrinsic values, determined at 10 GHz, exhibits a sharp peak at resonance. The effective surface reactance also shows huge variations around the resonance conditions and may be negative. Moreover, geometries resulting in an effective resistance smaller than the film intrinsic value have been found 相似文献
14.
Spectral gain hole-burning at λ0=1.53 μm was observed in an erbium-doped fiber amplifier at temperatures between 4.2 and 77 K. The hole width was found to broaden with temperature for T ⩾20 K according to a T1.73 law. From the data, the room-temperature homogeneous linewidth associated with the 1.531-μm transition in the 4I13/2-4I15/2 laser system was determined to be Δλh=11.5 nm for aluminosilicate fibers 相似文献
15.
The low-loss and uniform dielectric properties of sapphire make it attractive for high-performance microwave devices using high-temperature superconductors. YBa2Cu3O7-δ films have been deposited on oxide-buffered 5-cm-diameter wafers and demonstrated a surface resistance of 0.5 mΩ at 10 GHz and 77 K. Long (9-ns) stripline delay lines have for the first time been produced on these substrates and have a measured insertion loss of 1.5 dB at 6 GHz and 77 K. Design techniques appropriate for the dielectric anisotropy of sapphire are discussed 相似文献
16.
An optimal design for a sleeve balun with maximum choking on a coaxial cable is determined using a full-wave body of revolution finite difference time domain method with perfectly matched layer boundary conditions. An analysis of the sensitivity of choke length L and outer diameter R2 on choking effectiveness was carried out. A balun with L=77.5 mm (0.232λ0) and R2=8 mm on a cable with R1=2 mm (R2/R1=4) results in an S21 of -20 dB at 900 MHz and -15.5 dB at 2730 MHz. The isolation of the balun at 900 MHz is quickly degraded as the R2 /R1 ratio is reduced below 2. Increasing R2/R1 to 8, results in a reduction of optimum balun length L to approximately 0.215λ0, approximately 14% shorter than the typical recommended length for an 'ideal' quarter-wave balun 相似文献
17.
Saba F.M. Tagami M. Goodilin E.A. Shiohara Y. Enomoto Y. 《Applied Superconductivity, IEEE Transactions on》2000,10(3):1662-1666
Dielectric properties of both Nd1.9Ba1.1Cu 3O7+δ (NBCO-213) and Pr1.14Ba1.86Cu3O7-δ (Pr-rich PBCO) single crystals have been examined at low temperature. These materials have good lattice matching to high-Tc superconductors (HTS), but they are conductive at room temperature. Below 80 K, they are insulators with low dielectric constants, ε τ below 25, and low dielectric loss tan δ below 0.1 at 100 kHz. The value of ετ is suitable for insulators in integrated circuits using strip line widths of 10 μm order, providing short delay time, no excitation of surface wave, and low radiation loss. The value of tan δ is comparable to loss of superconducting surface resistance above 100 GHz. These results indicate the applicability for the insulator layers in multilayer superconducting electronic devices such as Single Flux Quantum (SFQ) circuits operated at high speed 相似文献
18.
Meschede H. Reuter R. Albers J. Kraus J. Peters D. Brockerhoff W. Tegude F.-J. Bode M. Schubert J. Zander W. 《Microwave Theory and Techniques》1992,40(12):2325-2331
An on-wafer measurement setup for the microwave characterization of HEMTs and high-T c superconductors at temperatures down to 20 K is presented. Both S -parameter and noise measurements can be performed in the frequency range from 45 MHz to 40 GHz and 2 GHz to 18 GHz, respectively, using standard calibration techniques and commercial microwave probe tips. Microwave measurements on a pseudomorphic FET and an AlGaAs-GaAs HEMT as well as investigations on a superconducting filter are presented to demonstrate the efficiency of the developed system 相似文献
19.
The possibility of remote sensing of surface water salinity in the decametric wave range is studied. The theoretical consideration of sensitivities to salinity variations proves the decametric range to be best for measuring small water salinities [0.3-5 parts per thousand ( 0/00) at 30 MHz]. The conclusion is confirmed by 30 MHz radar experiments, which show a good agreement with the in situ data in the range 0.3-30 0/00. Radar contrasts of about 0.35 db and 1.6 db are observed when salinity changes from 0.3 0/00 to 1.2 0/00 and to 30 0/00, correspondingly 相似文献
20.
Endoh A. Shinohara K. Watanabe I. Mimura T. Matsui T. 《Electron Device Letters, IEEE》2009,30(10):1024-1026
In this letter, we fabricated 30-nm-gate pseudomorphic In0.52 Al0.48As/In0.7Ga0.3As HEMTs with multilayer cap structures to reduce source and drain parasitic resistances; we measured their dc and radio-frequency characteristics at 300, 77, and 16 K under various bias conditions. The maximum cutoff frequency fT was 498 GHz at 300 K and 577 GHz at 77 K. The maximum fT exceeded 600 GHz at 16 K. Even at a drain-source voltage V ds of 0.4 V, we obtained an fT of 500 GHz at 16 K. This indicates that cryogenic HEMTs are favorable for low-voltage and high-speed operations. Furthermore, the present 30-nm-gate HEMTs at 300 K show almost the same fT values at the same dc-power dissipation as compared to 85-nm-gate InSb-channel HEMTs. The improvement of the maximum-oscillation-frequency f max values was also observed at 77 and 16 K. 相似文献