Characteristic Analysis Of Microstrip Antenna Based On Defected Ground Structure

Defected ground structure(DGS) was proposed by J. I. Park et al. on the basis of the photonic bandgap(PBG) structure in 1999. Similar with PBG strcture, DGS structure has the characteristics of band gap and slowwave. DGS can be used in restraining high order harmonics, improving the gain and bandwidth of antenna, improving efficiency and Q, fabricating low-pass filter and divider etc. DGS has simpler structure than PBG structure. So DGS is more compatible to be used in microwave and millimeter wave integrate circuits than PBG structure.Microstrip antenna is being used in wireless communication more and more intensiely because of its'excellent advantages such as light, small size, simple manufacturing, etc. On the other hand, the application of microstrip antenna is restricted by its disadvantages such as narrow band, high order harmonics, etc.In this paper, a DGS structure is simulated and the equivalent circuit of the DGS structure is derived. On this basis, microstrip patch antenna based on the DGS structure is designed. Simulated results and tested results show that the high order harmonics of microstrip based on DGS are restrained and radiation character is improved.What's more, in this paper, an Finite-Difference Time-Domain program is designed with Visual Fortran. A microstrip antenna is simulated by this program. The simulated results are similar with the tested results. This program can be expanded on this basis.