Lossy reflection mode dual-band bandstop prototype network based on hybrid elliptic filtering function

This paper presents a new hybrid dual-band band-stop (HDBBS) filter network based on predistortion reflection coefficient of hybrid dual-band lowpass elliptic filtering function with low Q resonators. It is shown that the hybrid filtering function is formed by the product of lowpass and highpass elliptic filtering functions. By scaling the highpass cut-off frequency, the inner passband of HDBBS can be adjusted to achieve any desired narrow band. Microstrip prototype is designed and fabricated to prove the concept. The simulated and measured results show a good agreement.