Compact LTCC band pass filter using high‐Q bondwire inductor for RF system‐in‐package applications

A low‐temperature cofired ceramics(LTCC)‐embedded bandpass filter (BPF) using a high quality (Q) factor (130) bondwire inductor is proposed for radio frequency (RF) system‐in‐package (SiP) applications. The usage of high‐Q bondwire inductors significantly improves the passband insertion loss (1.35 dB) compared with that (2.0 dB) of embedded spiral inductors at 5.25 GHz and also greatly reduces the device size to 1.000 × 1.500 × 0.675 mm 3 . The insertion loss and the size of the proposed bondwire filter are the best compared with those of open literature filters. Excellent tolerances of 1.9% and 4.4% are, respectively, measured for the cutoff frequency and the insertion loss. We expect the proposed bondwire filter play an important role to improve the performance and to reduce the sizes of RF SiP circuits. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1424–1428, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24390