A miniaturized surface mount bandpass filter implemented with substrate integrated coaxial line

In this work, a compact surface mount (SMT) filter implemented with the substrate integrated coaxial line (SICL) is presented to offer a practical solution for the applications that require flexible filter design. The shielded filter features a low profile and low cross-talk characteristics, and can be assembled or removed from the system conveniently. The six-pole SICL band-pass filter centered at 2.2 GHz is fabricated with standard multiplayer printed circuit board process and measured for experimental validation. Its transition structure and design procedure are illustrated. A minimal size of 27 mm ×16 mm and a bandwidth of 36.4% are achieved.