Self-packaged balanced bandpass filters with impedance transformation characteristic

Feng Huang, Khaled Aliqab, Jianpeng Wang*, Jiasheng Hong, Wen Wu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)
46 Downloads (Pure)


In this article, the co-design of novel self-packaged balanced bandpass filters (BPFs) integrated with the functionality of impedance transformation is presented for the first time. The proposed design is based on a modified branch-line structure, which is composed of two different branch lines and two identical coupled-line sections. Analysis results show that the considered filters can not only achieve Chebyshev equal-ripple responses with impedance transformation properties for the differential mode (DM) but also can efficiently improve the bandwidth of the common-mode (CM) rejection with resorting to this modified branch-line structure. Furthermore, according to the specified equal-ripple fractional bandwidth (FBW), in-band return loss (RL) level, and impedance transformation ratio {m} , the DM frequency response can be directly determined. Two design prototypes, the second-order balanced BPF with a 50-75-\Omega ( m= 1.5 ) impedance transformation and the third-order one with a 50-200-\Omega ( m= 4 ) impedance transformation, are implemented in self-packaged forms by using the multilayer liquid crystal polymer (LCP)-bonded printed circuit board (PCB) technology. Theoretical, simulated, and measured results are recorded in good agreement, well verifying the design concept.

Original languageEnglish
Pages (from-to)4353-4361
Number of pages9
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number11
Early online date30 Aug 2019
Publication statusPublished - Nov 2019


  • Balanced filter
  • impedance transformation
  • liquid crystal polymer (LCP)
  • self-packaged

ASJC Scopus subject areas

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Self-packaged balanced bandpass filters with impedance transformation characteristic'. Together they form a unique fingerprint.

Cite this