Study On Coplanar Waveguide Antenna Based On Defected Ground Structure

Since defected ground structure (DGS) was proposed by J. I. Park et al. in 1999, there has been an increasing interest in microwave and millimeter-wave applications of DGS. In this paper, we proposed the newly etched DGS with a interdigital in metallic ground plane. Compared with the dumbbell-shaped DGS, interdigital DGS has smaller etching areas and more sloping curve at the same frequency. The behaviour of the electromagnetic field in the interdigital DGS for a coplanar waveguide and a microstrip line have been investigated and the equivalent circuit is extracted. On this basis, its neural networks model is developed. The agreement between neural and HFSS results shows the networks model is precise and effective.In this paper, we design new antennas with interdigital DGS. Ultra-wide band(UWB) offer attractive features such as high data rate, low power expense, simple structure and low price, all these characteristics provide new opportunities to wireless communication. Coplanar waveguide antenna can reduce the surface-wave efficiently and DGS for CPW can be realized on the same plane, because CPW have a real uniplanar, 1-D structure.Firstly, the UWB coplanar waveguide antenna integrated with a interdigital DGS is designed. Compared with the common antenna, its simulated -10dB return loss bandwidth increase 600MHz. In other words, the ratio bandwidth increases from 84% to 103%, the ratio impedance bandwidth reaches 5:1. Secondly, a microstrip antenna integrated with a interdigital DGS is designed, we use interdigital DGS to take place the cirque dumbbell-shaped DGS used in the literature.Simulated results and tested results show that the high order harmonics of microstrip based on interdigital DGS are restrained and radiation character is improved while the etching area reduces 11%.