Putting forward a new kind of interdigital DGS, namely use interdigital capacitance to replace slot capacitance. Contrary to the slot capacitance, interdigital DGS can decrease filtering frequency effective, improve coupling of capacitance, increase the capacitance and also reduce multiple relationship between circuit sizes, beneficial to the design of the circuit. At the same time using interdigital DGS can decrease the area of DGS effectively, then the DGS can be used in the design of miniature devices. It has not been reported at home and abroad. In the last it designs microstrip antenna based on dumbbell-shaped interdigital DGS and compares the performance with ring dumbbell type (using slot capacitance). Actually it designs microstrip line antenna based on interdigital DGS. The result of simulation and test shows compared with ring dumbbell type DGS, interdigital DGS can filter higher harmonic effectively, at the same time the total etching area reduce to 11%, so it can reduce backward direction radiation , improve the radiation efficiency of antenna.