4H-SiC JBS rectifiers were designed with multiple floating guard ring termination using numerical simulation methods, and were fabricated using a simplified self-aligned process sequence. Simulations were used to investigate forward voltage drop and reverse electric field shielding with respect to JBS spacing. Optimized devices were fabricated on 30 mum lightly doped n-epitaxial layers. JBS diodes exhibited 2.5kV blocking capability with reverse leakage currents below 2x10(-5) Acm(-2) at 2kV, and a forward voltage drop of 2.95V at 100Acm(-2).