Design of IPD-based wideband bandpass filter chips with controllable transmission zeros

ABSTRACT

In this brief, two novel wideband bandpass filter (BPF) chips with independently controllable transmission zeros are proposed. BPF I uses bridge T-type highpass and lowpass structures cascaded to achieve wideband filtering. On this basis, BPF II adds three pairs of LC resonant circuits to add additional transmission zeros while retaining the lowpass structures. The analytical methods of odd-even mode and ABCD matrix to S-parameter matrix are used to analyze and calculate two designs. For validation, two prototypes of proposed BPFs in integrated passive device (IPD) have been designed, fabricated, and measured. One prototype operates at 5.3 GHz, providing a 3-dB fractional bandwidth (FBW) of 46.9%, while the other prototype operates at 4.7 GHz, providing a 3-dB FBW of 57.6%. Moreover, the two chips exhibit minimum insertion losses of 1.55 dB and 1.5 dB, respectively, while occupying compact sizes of 2.27 mm × 0.83 mm and 1.7 mm × 0.88 mm.

KEYWORDS:

• Bandpass filter (BPF)
• controllable transmission zeros
• integrated passive device (IPD)
• lumped elements

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

Additional information

Funding

This work was supported by the National Natural Science Foundations of China [No. 62320106002, No. U22A2014, and No. U20A20203], and the Fundamental Research Funds for the Central Universities [2021XD-A07-3]. In addition, Miss. W. Zhang’s Master’s Dissertation in 2024 includes this paper as chapters.