CPW DC Pass Filters for RF Energy Harvesting

Two different coplanar waveguide DC pass filters are introduced in this paper. The proposed coplanar filters have both the filter conductive lines and the ground plane on the same side of the substrate, that gives two advantages of wider bandwidth than the microstrip structure and avoiding the via holes through the substrate when connecting the devices such as diodes, capacitors or inductors. The proposed filters are developed to be integrated with rectenna systems after the rectifier circuit. The first DC pass filter consists of one series straight short end stub, and three shunt bent short end stubs. These stubs are used to reject specific harmonics according to the stub length and position. The second DC pass filter is coplanar fan stub filter. It consists of single stub with fan shape which achives wider rejection frequency bandwidth with smaller area than the first filter. The fan shape stub DC filter shows good performance in the rejection from 1.8 GHz to 10 GHz.