Ferrite circulators are required to provide isolation between mismatched cavity and RF source. As a part of indigenous circulator development program, a 476 MHz strip line circulator has been designed and modeled using CST Microwave Studio, for RF system of Infra-Red Free-Electron Laser at RRCAT, Indore. Circulator subsystems viz. calcium vanadium garnet disk resonator, circulator geometries, and biasing magnetic field have been optimized in above resonance mode. Thermal analysis by means of heat diffusion profile and temperature rise using thermally coupled simulations gives 15 °C maximum temperature rise at 1 kW average RF power. Based on this design, prototype strip line ferrite circulator has been developed and tested. Insertion loss of -0.35 dB and -20 dB isolation have been observed. This paper presents the design aspects, optimization of strip line geometry, electromagnetic and thermal simulation of ferrite circulator.