2.4GHz Band Pass Filter Architecture for Direct Print Additive Manufacturing

This paper presents the first capacitively-loaded cavity band pass filter (BPF) that is compatible with direct print additive manufacturing, a hybrid technique that combines fused deposition modeling and micro-dispensing. The single resonator achieves a measured unloaded quality factor of 160–320 over the frequency range from 2.4 to 6.8 GHz. The two pole filter is designed using a coupled-resonator approach to operate at 2.44 GHz with 1.9% fractional bandwidth. The simulated and measured insertion loss is 3.8 dB and 4.2 dB, respectively. Fused deposition modeling is used to deposit acrylonitrile butadiene styrene (ABS) to form the stand-alone resonator and filter structures (relative permittivity of 2.7 and loss tangent of 0.008) and silver paste (Dupont CB028) is used to form the conductive parts.