Design of On-Chip Ultra-Miniaturized Low-Loss Dual-Band Bandpass Filter in LTCC for 5G Applications

In this paper, a novel on-chip ultra-miniaturized dualband bandpass filter (D-BPF) using the low-temperature cofired ceramic (LTCC) technology is proposed. To realize the ultra-miniaturization of the proposed D-BPF, the vertical configuration for the lower and upper bands is implemented. The low insertion loss and wide passbands can be obtained by using direct coupling between resonators. Furthermore, the simplified LC model of the proposed layout is given and analyzed. For verification, the proposed DBPF is designed, simulated, fabricated and measured, respectively. Finally, the D-BPF used in the sub-6 GHz band with the core size of 3.3 mm × 2.8 mm can cover from 3.01 to 3.79 GHz and from 4.77 to 5.33 GHz within the condition of │S
1
1
│ < -15 dB.