Design of a miniaturized balun using Low Temperature Co-fired Ceramic Technology

This paper presents a novel miniaturized balun using Low Temperature Co-fired Ceramic (LTCC) Technology. Lumped capacitors are employed in the balun, so that the electrical length of the coupled line can be reduced greatly compared to conventional Marchand balun. The even-odd mode method is used to analyze it, and a novel three dimensional (3D) structure is presented. A spiral broadside coupled strip-line is adopted to realize the proposed miniaturized multi-layer balun. The proposed balun achieves ±0.1dB amplitude balance and ±0.5° phase balance, with over 20 dB return loss from 2.4 GHz to 2.5 GHz, which can be widely used as a standard component in wireless communication.