A Structure Reuse Method for Realizing Large Frequency Ratio Dual-Band Multi-Channel Integrated Filters

A structure reuse method based on mode composite transmission line (MCTL) is proposed to realize compact large frequency ratio multi-channel integrated filters in this brief. The MCTL is composed of a fully shielded transmission line (
i.e.,
substrate integrated coaxial line (SICL)) and a semi-open transmission line (
i.e.,
microstrip line), where the outer conductor of fully shielded transmission line acts as the signal conductor of the semi-open transmission line to achieve structure reuse. A filter prototype integrates one sub-6G channel and one Ka-band dual-channel is firstly designed to confirm the feasibility of this structure reuse method. Then, a prototype comprising one sub-6G channel and four Ka-band channels is also designed to validate the possibility of improving the reuse efficiency furtherly. Both the two prototypes were fabricated and measured. Measured results are all in good agreement with the simulated ones, validating the correctness of this design method.