A multigate Schottky diode comprisingan electrically conducting active semiconductor region;first and second electrically connected metallic contact arms on the active semiconductor region forming ohmic contacts therewith;the ohmic contacts being spaced apart on the active semiconductor region to define a gate receiving channel therebetween. Each sensor chip includes a wireless communication transmitting block, a temperature sensor, a signal processing block, and an energy harvesting circuit. A second catheter includes a second distal end region, a second outer surface defining a second lumen, and a second transition region transitioning cross sections of the second outer surface and the second lumen.