This article presents a transformer‐based coupled‐resonator structure to design a bandpass filter (BPF) using integrated passive device technology on glass substrate. The use of the transformer not only greatly reduces the size of the bandpass filter but also easily uses the coupling to control the bandwidth of the filter. Using such a transformer‐based coupled BPF structure not only provides the advantage of compact size but also creates extra transmission zeros to enhance roll‐off rate or desired stopband rejection. Measured results verify the validity of this design methodology and show good agreement with simulated ones. For demonstration purpose, two example filters are implemented with different bandwidths. Both good performance and miniaturization are achieved for the proposed filters, and the expected transmission zeros are also observed. The filter can be embedded to wafer‐level 3D packaging and integration for wireless system‐in‐package applications. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:3–7, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26511