Ka-band bandpass filter-using a cpw structure technology with copper on an AL ₂O ₃ substrate

The performance of a Ka-band bandpass filter (BPF) was evaluated using a coplanar waveguide (CPW) topology on an Al ₂O ₃ substrate. A copper (Cu) metallization was used to improve the characteristics of the filter. The measured results of the BPF with a chip size of 2423 × 424 μm showed a return loss of 25.3 dB and an insertion loss of 0.6 dB at 27 GHz. A comparative investigation of the simulation and experimental results showed better agreement between them. The overall filter characterization exhibited a broad bandwidth of 18.8 to 38.2 GHz, a high return loss, and a low insertion loss that demonstrated that the BPF showed favorable RF characterization in Ka-band with a compact microwave monolithic integrated circuit (MMIC) size. The S-parameter of the coupled resonating filter was also simulated with the Advanced Design System (ADS) and the effect of the electric-magnetic coupling within the Ka-band layer were computed with the HP-Momentum.