William Yu (LTCC Design Engineer II), Mini-Circuits, presenting at Interlligent UK's 2024 RF & Microwave Design Seminar.
LTCC filters have been traditionally designed to deliver around 30 dB of stopband rejection. Mini-Circuits has innovated LTCC filter capabilities to produce novel designs (BFHK series) with rejection up to 90 dB and beyond. However, these high-rejection designs require a launch from a stripline to achieve their full rejection performance due to the coaxial input of the RF pads. This constraint poses a challenge for PCB designers looking to incorporate the BFHK-series onto their microstrip and coplanar waveguide traces. This presentation introduced an interposer board that allows universal adaptation of BFHK-series LTCC filters (BFHKI-series) to be mountable onto microstrip and coplanar waveguide traces. Implementations of the BFHKI-series onto both stripline and coplanar waveguide launches are presented and their performance compared with the base BFHK-series, demonstrating significant performance benefits over traditional LTCC filters and other filter technologies.