Miniaturized lowpass filters with out-of-band improvement by using defected ground plane structure as shunt series stubs

This paper presents the design of miniaturizedand low-spurious-response lowpass filters using defected ground plane structure. In our structure, the capacitances and inductances are realized thanks to open-circuited parallel stubs and short-circuited serie stubs respectively. The short-circuited serie stubs are achieved by using defected ground plane structure @GS). This induces an important size reduction. Moreover, the different transmission zeros can be used to control out-of-band response. Finally, filters are presented in multilayer technology.