Wideband High Selectivity Filter Chips With Adjustable Bandwidth Based on IPD Technology

In this brief, two kinds of wideband high selectivity passband filter chips with adjustable bandwidth are proposed. Independent controllable transmission zeros are introduced on both sides of the passband by LC resonators. Two designs are analyzed and calculated by means of odd-even mode analytical method and ABCD matrix to S-parameters matrix method. Finally, integrated passive device (IPD) technology was used to process two versions of broadband and narrowband filters for each design, with a total number of four filter chips. The measured results show that 3-dB fractional bandwidth (FBW) of the first design are 19.3% and 83.6% respectively, which have verified a large degree of freedom in bandwidth control. In addition, the return loss of four chips is better than 17 dB, the optimal insertion loss ranges from 1.31 dB to 2.73 dB, and the stopband rejection is better than 25.2 dB, indicating excellent overall performance.