-7-Cross Patch Electromagnetic Band Gap Incorporated with Rectangular Patch Microstrip Antenna

7) M. K. A. Rahim, O. Ayop, “Cross Patch Electromagnetic Band Gap Incorporated with Rectangular Patch Microstrip Antenna”, 2008 Asia Pacific Microwave Conference (APMC 2008), 16 - 20 Dec 2008.

Introduction:

This paper discussed and analyzed the properties of the antenna with and without cross patch EBG structure as an artificial ground plane in simulation and measurement. The new structure of EBG has been designed, simulated, fabricated, and tested before integrate the structure with microstrip patch antenna.

Design:

Design, simulation and fabrication of cross patch EBG structure. The 3 by 3 cross patch EBG structure has been designed, simulated and fabricated. The structure used in this research is FR4 board which has dielectric constant 4.8 and thickness 1.6. The EBG structure consist 9 elements of cross patch grounded with vias. A 50 ohm transmission line is used on a supporting material to predict the band gap characteristic of the structure. The simulated and measured S21 value is shown in figure 2 where this EBG structure is designed at 2.4 GHz frequency band. From the graph, the simulation result shows that the band gap frequency of the 3 by 3 Cross patch EBG structure from the simulation is from 1.935 GHz to 2.507 GHz. The bandwidth of the band gap measured for the value of S21 below -20 dB is 25.9%. After fabrication process, the band gap frequency measured is from 2.26 GHz to 2.57 GHz. The bandwidth of the band gap is decreasing to 12.86%. Although the bandwidth of the EBG structure is reduced compared to the simulation, this bandwidth is large enough to cover the bandwidth of the fabricated microstrip antenna.