A fully embedded LTCC stripline parallel coupled BPF for 40 GHz BMWS application

A low-loss fully embedded bandpass filter (BPF) is proposed using low-temperature cofired ceramic (LTCC) technology with enhanced stopband characteristics for the broadband multimedia wireless system (BMWS) applications. The measured insertion loss was as small as 1.7 dB at a center frequency of 41.8 GHz, and the return loss was 10.2 dB, including the loss associated with two stripline-to-CPW transitions. This six-layer BPF showed 3-dB bandwidth of 8.4% at a center frequency of 41.8 GHz and suppressed the local oscillator (LO) signal to 20 dB at a local oscillator frequency of 38.8 GHz.