Integration of planar UWB antennas in real-life systems

A planar UWB monopole antenna shows very good radiation characteristics in an isolated scenario. However, in practice it must eventually be placed on or integrated into a printed circuit board (PCB). It is well known that this will degrade the antenna performance due to the field coupling between the antenna and the ground. In this paper, the integration of a CPW fed monopole antenna with a relatively large PCB is studied. To avoid the direct current flow between the antenna and the PCB, the antenna structure and the PCB ground are printed on different layers. To feed the antenna a microstrip to CPW transition is utilized. In order to maintain the radiation characteristic of the antenna when integrated in to the PCB, two pairs of quarter wavelength stubs are placed on the ground plane side.