Switching threshold characteristics of the shaped Josephson junctions for tree-decoder use were investigated theoretically and experimentally. Side lobe suppression was successfully achieved by a constricted full window junction structure, whose optimum constriction could be predicted by Fourier integral of junction width function. Side lobe suppression ratio as large as 16 was obtaind for constriction ratio K/L1/3, and junction length L/λ03.3.

Improvement in circuit performance of Josephson logic devices is described and discussed. A high sensitivity switching gate of asymmetrical two junction interferometer is proposed, in which the Josephson threshold current of the junctions is unequal to each other but the bias feeding point is selected so as to balance inductance threshold current product on the left and the right hand side branch. Transmission lines with characteristic impedance as high as 4Ω were realized on a new superconducting ground plane structure with SiO2 overlying insulation. High resistivity resistor material of gold-indium alloy was also developed for resistive termination. A series-connected 4 stage OR gate chain was experimentally constructed with the present switching gates, transmission lines, and termination resistors. The circuit performance measurements demonstrated that the average speed power product was as small as 0.9 fJ per single stage.

In this paper, we propose a new network organizing method for packet radio networks, a layered self-organizing method. In the layered self-organizing network, whole service area is divided into multiple sub-areas and one base station is settled in each sub-area. Communication links are settled in shorter time than the conventional self-organizing method. We evaluate the network organizing performance of the method by using simulations.