We suggest a new design of rapid single flux quantum (RSFQ) logic circuits which is based on a single superconducting layer and does not require a superconducting ground plane. Small inductances of about 10 pH, obligatory for RSFQ circuits, are formed as narrow slits of widths comparable to the London penetration depth (&bartil;0.15 &mgr;m). The design allows us to decrease the geometric size of the RSFQ cell. Test circuits with YBaCuO grain boundary junctions on asymmetric 32° Y– ZrO2bicrystals were used to measure the slit inductance per unit length and the mutual inductance of neighboring slits. A typical inductance of a 0.4 &mgr;m slit was found to be 0.7–0.8 pH/&mgr;m. ©1995 American Institute of Physics.