Synopsis: In a wireless communication system, signal interference will cause a substantial degradation in signal quality. In order to suppress the interference of the adjacent channel signals high selectivity filters with transmission zeros at stopband are highly desirable in modern communication system. This talk discusses the state of the art, showing the current approaches of
transmission zeros realization in microwave filter and their design challenges. The practical issues will also be discussed
and shown with some new technology breakthroughs achieved to address the issues.