SELF-RADIATION POWER AND MICROWAVE COUPLING OF YBCO JOSEPHSON-JUNCTION ARRAYS ON BICRYSTAL MGO SUBSTRATES

We have studied the microwave properties of the Josephson junction arr ay by measurement of Josephson self-radiation power and Shapiro-steps. The serial-parallel and parallel Josephson junction arrays were prepa red with and without additional inductive coupling lines. The maximum detected power of 22 GHz from the serial-parallel array is about 25 pW and its peak point revealed a good quality of frequency-locking and e xactly satisfied the Josephson voltage-frequency relationship. Althoug h the parallel array has similar physical properties of average critic al current and normal resistance of Josephson junctions to serial-para llel array, the maximum detected power is only about several tens of f W. The received power of serial-parallel array is higher than that of the parallel array for the same intensity of irradiation power. (C) 19 98 Elsevier Science B.V.