Design And Production Of MMIC Front-end Receiver Based On The Josephson Junction

Today, the mm Wave, microwave and RF technology is more pervasive than it has ever been. The development of these technologies is striding hand in hand with the developing of new materials trough the simple conductors and dielectrics, semiconductors, superconductors to metamaterials. Previously, the development of the materials has given n-times performance improvement for the microwave circuits, however, in case of the superconducting materials it gives improvements in several orders of magnitude in the key performance parameters.The materials properties of the superconductors and suitable substrates have been analyzed in this project. Based on the analysis of high-temperature superconducting material necessary parameters have been derived, which allowed to design a monolithic microwave integrated circuit of a front-end receiver. The MMIC receiver consists a coplanar waveguide log-periodic dipole antenna, transition from the coplanar waveguide to a microstrip, a microstrip resonator, the Josephson junction, ultrawideband bandpass filter, and feeding system. The high-temperature superconducting MMIC provides a down conversion from 37.5 GHz to 7.5 GHz with the bandwidth more than 7 GHz.The simulation results have been obtained in Sonnet? Software by applying the two-fluid model. The major components of HTS MMIC are:? Antenna. The obvious improvement for superconducting antennas is in the radiation efficiency of small antennas and superdirectional arrays. Antennas which are around the size of one wavelength are normally fairly efficient and superconductors cannot greatly help. Speaking of transmitting antennas, the power handling capabilities increases significantly with applying of the high-temperature superconductors. For the receiving antennas it important to have noise as low as possible. The simulation results of log-periodic dipole antenna show a good performance(VSWR is lower than 2) in the selected bandwidth 30 – 50 GHz. The coplanar waveguide realization of the log-periodic dipole antenna excludes necessity of using baluns and provides relatively good broadband impedance matching.? Transition from coplanar wave guide to microstrip. Since the log-periodic dipole antenna has a CPW feeding network, the transition from CPW to microstrip has been done with minimum losses. The extremely small losses have been achieved by circular transitions of ground planes for a smooth conversation between microstrip line mode and CPW mode.? Resonator. The local oscillator frequency is pumped through the gap coupled microstrip half wave resonator. Using the simplicity of resonator, we have shown several important approaches and drawbacks in out design.? The Josephson junction. The key feature in the Josephson junctions is a thin uniform insulating barrier or normal conducting interlayer between two superconducting electrodes, which provides controllable weak exchange of Cooper pairs and quasiparticles. In this project, we have used an intrinsic Josephson junction. Due to a high dependence of the Josephson junction parameters on fabrication processes, it is required to do measurements for the particular layout, and it has been suggested as a continuing project.? Filter. An ultra-wideband band-pass filter have been chosen to meet our requirements. The filter consists dual-line quarter wave coupling structures and a dual mode ring resonator. The simulation results show the out of band rejection is better than 90 d B, except for the harmonic responses. The insertion loss is less than 4*10-4 d B, while simulation of the gold filter with the same topology shows insertion loss from 1.6 to 7 d B.