Defected ground structure have been always an area of interest for research in millimetre waves and microwaves. In this paper, the different parameters of a defected ground structure which helps in lowering cut-off frequency and resonant frequency of microstripline have been analysed. A circularly shaped defected ground structure which is equivalent to LC model circuit has been simulated and its performance characteristics are studied. As the complexity of a structure increases, due to slow wave effect there is variation in the cut-off frequency and resonant frequency. These variations are useful in size, mutual coupling reduction and harmonic suppression which help in designing of various microwave circuit. © 2013 IEEE.