A Novel 3D On-Chip Bandpass Filter for Wireless Communication

To further reduce the size of integrated passive devices, a bandpass filter based on three-dimensional integrated passive technology is introduced, which has the characteristics of small size, ultra-wide stopband and high rejection. The proposed filter selects the appropriate topology and cleverly designs three vertical transition structures to complete the three-dimensional transmission of signals, thus realizing the expansion of integrated passive devices from plane to three-dimensional. According to the simulation results, its size is only
$1.273\text{mm}^{\ast}1.033\text{mm}^{\ast}0.28\text{mm}$
. The centre frequency of the proposed filter is 2.8 GHz, and its rejection on both sides of the passband is more than 40 dB. What's more, the upper stopband ranges from 3.25GHz to 31.8GHz below 30dB.