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The experimental results of mm-wave coherent emission from a high temperature superconducting bicrystal Josephson junction array embedded in a Fabry-Perot resonator are reported in this paper.The mm-wave coherent emission from the series junction array results from the interaction of the junctions with the substrate serving as the dielectric resonator as well as the Fabry-Perot resonator.The central frequency of emission of a Josephson junction array containing 166 bicrystal junctions was 75.84 GHz,and the detected emission power was about 10 pW at 77 K.

We proposed a method for implementing impedance matching and phase locking of Josephson junction arrays based on Hes previous report on the coupling mechanism of a millimeter wave radiation to bicrystal Josephson junction arrays embedded in a Fabry-Perot resonator，and relevant electromagnetic simulations and numerical calculations were performed. A bicrystal Josephson junction array was fabricated on a YSZ bicrystal substrate，and embedded in a Fabry-Perot resonator. Impedance matching was implemented by integrating an optimized half-wavelength dipole array fed in series with the junction array，and numerical calculations showed that the radiation efficiency of a single junction reached 94%. Through making good use of the radiation characteristics of the antenna array and optimizing the model，the FP resonator and the substrate can be driven to resonate in proper modes respectively，which benefits the high frequency electromagnetic coupling between the junction array and the resonators. The numerical simulations proved that this method is effective for realizing self-voltage locking and mutual-phase locking of junction arrays. The method proposed in this paper and calculation results are valuable for guiding the applications of Josephson junction arrays in THz signal generators and voltage standards.

The millimeter wave irradiation characteristics of a Tl-2212 high-temperature superconducting thin film bicrystal Josephson junction embedded in a hemispherical Fabry-Perot resonator was studied. The coupling characteristics of the bicrystal Josephson junction with the Fabry-Perot resonator have been investigated experimently, showing that it was greatly affected by the factors such as the location of the sample in the open resonator, the angle between them, the pattern of the junction and the distance between the two reflecting mirrors of the resonator. The optimized coupling between Josephson junction and applied microwave was achieved by refined adjustment of the factors. In this case, 9 orders distinct Shapiro steps were observed. Taking advantage of the Fabry-Perot resonator technique, the coupling problem between high-temperature superconducting thin film Josephson junction and applied millimeter wave was well solved, which is of significance for the research on radiation and detection of millimeter wave and terahertz wave of high-temperature superconducting Josephson junction.

A linear phase high temperature superconducting （HTS） filter fabricated on LaAlO3 substrates is presented. The designed passband of the HTS filter is 10 MHz and the group delay ripples over 80% of the passband is less than 20 ns. The filter consists of novel resonators, which are able to minimize the spurious couplings between resonators. As a result, the filter shows not only the linear phase characteristic but also the symmetrical frequency response. The measured passband is 9.85 MHz. The return loss is better than 16 dB and the out-of -band rejection is better than 80 dB. The measured group delay ripples is about 20 ns, which is in good agreement with the simulated result.

Tl-2212 bicrystal Josephson junctions on SrTiO3 substrates have been fabricated. The I-V characteristic of a Josephson junction under microwave radiation were measured，and microwave induced steps were observed in accordance with the Josephson frequency-voltage relationship. The RCSJ model including noise of bicrystal Josephson junction was constructed through numerical simulation，and the results of simulation were in good agreement with the experimental data. Using the RCSJ model，we investigated the effect of noise on the dynamic characteristics of Josephson junction through simulation，and explained the phenomenon of reduced height and increased breadth of the minima of microwave induced steps. We proposed that the effective noise temperature should be the sum of operational temperature and equivalent temperature of the external noise.

The preparation of CeO2 buffer layers on r-cut sapphire substrates by in situ two-temperature process and Tl-2212 superconducting films has been studied. The results of XPS and AFM show that this simple process of growing buffer layer produces CeO2 film with smooth surface, which can hold back the diffusion of Al from sapphire into Tl-2212 film. The 530 nm thick Tl-2212 films grown on the CeO2 buffer layers subsequently possess excellent electrical property. The films have a high transition temperature （Tc =108.2 K）, a high critical current density （Ｊc=6.58 MA/cm2at 77 K and zero applied magnetic field） and a low surface resistance （Rs=185 μΩ at 10 GHz and 77 K）, and their superconductivity can be improved significantly.

In this study, the surface morphology evolution and the change of the phase structure of r-cut sapphire substrates annealed at different temperatures for different time in O2, and the effects of annealing conditions on the growth of CeO2 and Tl-2212 films, were investigated by AFM and XRD. The results of AFM show that the local steps on the substrate annealed at 1000℃ is formed firstly, and then the multilayer terrace-and-step structure, yielding from prolonging annealing time, evolves into wide terrace-and-step structure with ultrasmooth terrace through the coalition of initial localized steps, which slightly tilts to the surface. XRD measurements show that the CeO2 films prepared on r-cut sapphire annealed at the optimized conditions and the 500 nm thick Tl-2212 films grown on the CeO2 buffer layers subsequently possess excellent in-plane and out-of plane orientation, and the annealing temperature and annealing time have strong effect on the crystalline quality of substrates and CeO2 films. The Tl-2212 films have a high transition temperature (Tc=104.7 K), a high critical current density (Jc=3.5 MA/cm2 at 77.3K and zero applied magnetic field) and a low surface resistance (Rs=390μΩ at 10GHz and 77K).

The model of capacitively coupled intrinsic Josephson junction array was constructed with the software PSpice. Taking advantage of this new model, we investigated the behavior of capacitively coupled intrinsic Josephson junction array driven by constant current. The time domain wave, freguency spectrum, fractal dimension and phase portrait were obtained. Compared with the uncoupled array, chaotic behaviors were found firstly in the capacitively coupled intrinsic Josephson junction array. The results are valuable for the research and application of intrinsic Josephson junction arrays.