Embedded passive device technology for wireless mobile devices

Abstract

Purpose

The purpose of this paper is to present the design and manufacture of embedded passive devices in organic substrates.

Design/methodology/approach

Low cost and high performance duplexers have been designed for WiMAX front‐end modules with multi‐layered organic substrates. Band‐pass filters (BPFs) and duplexers for the WiMAX FEM have been embedded in organic substrates. In addition, a new organic substrate manufacturing process has been proposed in order to improve the tolerance of embedded passives in organic substrates.

Findings

The overall size of FEM, which includes PA and bypass capacitor, is 5.4×4×1.5 mm. BPFs and duplexer show good electrical performances with low insertion loss and high attenuation. The dual‐band FEM with embedded passive components incorporates the duplexers including 2 and 5 GHz BPFs. The dimensions of BPFs and duplexer are 1.65×1.8×0.12 mm, 1.32×1.2×0.12 mm and 2×2×0.6 mm, respectively. The integrated dual‐band BPFs show an insertion loss < 1.8 dB in path band and 22‐40 dB attenuation performance in rejection band. The newly proposed fabrication process improves the tolerance for embedded capacitors in the organic substrate. This new process provides two main advantages. First, the flat coating process is not required. Second, it has a better copper pattern tolerance since the pattern is achieved with the addictive process. The tolerance of capacitances produced by the newly proposed process is compared with one manufactured by the conventional etching process. The newly proposed process provides a better capacitance tolerance.

Research limitations/implications

In future studies, it is suggested that the tolerance study should include other variations such as thickness, alignment and material properties.

Practical implications

The paper's findings can be used for designing and manufacturing embedded passives devices for wireless applications.

Originality/value

This study shows a technology development in the area of embedded passive devices in organic substrates.

Citation

Yi, S., Kim, K., Lee, D., Kim, H. and Jung, T. (2013), "Embedded passive device technology for wireless mobile devices", Microelectronics International, Vol. 30 No. 1, pp. 33-39. https://doi.org/10.1108/13565361311298213