In communication system duplexing the antenna to work as a transmitter as well as receiver radiator is very important to achieve compact size, high performance and light weight. The device that can suitably be used for this kind of radiation is the Circulator. Designing a circulator involves integration of different components and materials. Ferrite, being a key material will provide non-reciprocity property and impart Faraday's rotation. Designing of such circulator is governed by RF design, magnetics and electronics. Bandwidth requirement for such circulator is much larger. Junction circulators does not provide enough bandwidth. In this paper, optimization of bandwidth is done by using lumped element matching technique. The scope of ferrite and air gap can be determined easily by using this lumped element method and these has been experimentally confirmed. It was found that when dc magnetic field is uniformly distributed, the demagnetizing magnetic field gives optimum performance. The ferrite material usually has nonlinear effects and hence here a large spin wave ferrite material is used. This is an important design factor for high-bandwidth circulator which require insertion loss to be minimum. The aim is to make efficient use of available bandwidth which is 100 MHz for a practical circulator and is enhanced to 900 MHz with centre frequency 915 MHz. The other parameters observed are Voltage Standing Wave Ratio (VSWR), insertion loss, isolation loss. The geometry of the circulator is built and meshed using COMSOL Multiphysics. The graph shown in the figure represents the Scattering matrix parameters which indicates the reflection and transmission coefficients.