Microwave Switchable Bandstop Filter Using Stepped Impedance Resonator

The exponential growth of modern wireless communications market creates an unprecedented demand for compact-size, low-cost, high-performance and reconfigurable filter. Due to this recent development, much attention has been devoted to compact microwave reconfigurable filters. The first condition that must be met by a reconfigurable filter is that it must be capable of inducing microwave transmitters and receivers to be adaptable to multi-band operations using a single filter, which is highly desirable in the current wireless communication technology. Among the many techniques found in recent literature, reconfigurable filters for cognitive system prove to be a popular technique. The conventional structure exhibits high losses, low tuning speed and large circuit size. These constraints have created the need for microwave reconfigurable filters that make wireless communication and cognitive radio systems to work with other devices across multichannel. In this book, several novel structure using stepped impedance resonators have been proposed, designed, manufactured and tested.