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Simulation of dielectric resonator for high-Tc radio frequency superconducting quantum interference device 下载免费PDF全文
Nowadays, the high-critical-temperature radio frequency
superconducting quantum interference device (high-$T_{\rm c }$ rf
SQUID) is usually coupled to a dielectric resonator that is a
standard $10\times 10\times 1$~mm3 SrTiO$3 (STO) substrate
with a YBa2Cu$3O$_{7 - \delta }$ (YBCO) thin-film flux
focuser deposited on it. Recently, we have simulated a dielectric
resonator for the high-$T_{\rm c }$ rf SQUID by using the ANSOFT High
Frequency Structure Simulator (ANSOFT HFSS). We simulate the
resonant frequency and the quality factor of our dielectric
resonator when it is unloaded or matches a 50-$\Omega$ impedance.
The simulation results are quite close to the practical
measurements. Our study shows that ANSOFT HFSS is quite suitable for
simulating the dielectric resonator used for the high-$Tc rf
SQUID. Therefore, we think the ANSOFT HFSS can be very helpful
for investigating the characteristics of dielectric resonators for
high-$Tc rf SQUIDs. 相似文献
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The electromagnetic field of a human heart system is a bioelectromagnetic field. Electrocardiography (ECG) and magnetocardiography (MCG) are both carriers of electromagnetic information about the cardiac system,and they are nonstationary signals. In this study,ECG and MCG data from healthy subjects are acquired; the MCG data are captured using a high-T c radio frequency superconducting quantum interference device (HTc rf SQUIDs) and the QRS complexes in these data are analysed by the evolutionary spectrum analysis method. The results show that the quality factor Q and the central frequency f z of the QRS complex evolutionary spectrum are the characteristic parameters (CHPs) of ECG and MCG in the time-frequency domain. The confidence intervals of the mean values of the CHPs are estimated by the Student t distribution method in mathematical statistics. We believe that there are threshold ranges of the mean values of Q and f z for healthy subjects. We have postulated the following criterion: if the mean values of CHPs are in the proper ranges,the cardiac system is in a normal condition and it possesses the capability of homeostasis. In contrast,if the mean values of the CHPs do not lie in the proper ranges,the homeostasis of the cardiac system is lacking and some cardiac disease may follow. The results and procedure of MCG CHPs in the study afford a technological route for the application of HTc rf SQUIDs in cardiology. 相似文献
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A new high-T_c (HT_c) rf SQUID working at around 1.3GHz has been developed to avoid electromagnetic interference such as growing mobile communication jamming. This new system works in a frequency range from 1.23 to 1.42GHz (centred at 1.3GHz), which is not occupied by commercial communication. The sensor used in the 1.3GHz rf SQUID is made of a HT_c coplanar superconducting resonator and a large-area HT_c superconducting film concentrator. We have achieved in the 1.3GHz HT_c rf SQUID system a minimal flux noise of 2.5×10^{-5}Φ_0/\sqrt{Hz} and a magnetic field sensitivity of 38fT/\sqrt{Hz} in white noise range, respectively. The effective area of the concentrator fabricated on a 15×15mm^2 substrate is 1.35mm^2. It is shown that the 1.3GHz rf SQUID system has a high field sensitivity. Design and implementation of 1.3GHz HT_c rf SQUID offers a promising direction of rf SQUID development for higher working frequency ranges. 相似文献