Development of a wide-tuning range and high Q variable capacitor using metal-based surface micromachining process

Huang, I‐Yu; Sun, Chian-Hao; Tasi, Han-Cheng; Chou, Che-Ya; Huang, Chih-Fang

doi:10.1016/j.sna.2008.11.009

Cited by 7 publications

(2 citation statements)

References 24 publications

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“…Variable capacitors are key elements in many electronic devices due to their ability to provide a wide tuning range (Wan and Lowther, 2007). Their fabrication has been usually based on microelectromechanical system (MEMS) technologies in order to fabricate capacitors with varying cantilever length (Luo et al, 2006), or glass-based doublecross-type variable capacitor (Huang et al, 2009), or ultrathin silicon wafers, SU-8 bonding and deep reactive ion etching micromachined based variable capacitor with parallel plates (Xiao et al, 2003) or vertical cantilever based variable capacitor fabricated using deep C-ray lithography and electroplating (Achenbach et al, 2007). However, abovementioned micromachined capacitors have been usually fabricated using either masks process or additional postprocessing steps, which are both costly and time consuming.…”

Section: Introductionmentioning

confidence: 99%

Combining rapid prototyping techniques in mechanical engineering and electronics for realization of a variable capacitor

Stojanović

Mandić²,

Ćurčić³

et al. 2014

Rapid Prototyping Journal

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Purpose -This paper aims to present combination of poly-jet technology and ink-jet technology in a multidisciplinary way in order to exploit advantages of these rapid prototyping techniques in manufacturing a demonstrator device -a variable interdigital capacitor. Design/methodology/approach -The platform of 3D complex geometry, with optimized design and cavity under the capacitor's fingers (plates), was fabricated using Alaris 3D printer, whereas silver conductive segments were fabricated using Dimatix ink-jet printer and thanks to the mechanical flexibility the platform has been covered using these segments. Findings -When one side of the capacitor's structure changes angular position (in the range from 0 to 908) with reference to the fixed part, the variation in total capacitance is obtained. The total capacitance decreases (in the range from 20.2 to 1.5 pF) with decrease in effective overlapping area for the variation of angular position from 0 to 908 The maximum measured tuning ratio for the proposed design of the variable capacitor was 13.5:1. Research limitations/implications -Presented variable capacitor can be used for detection angular position in the range from 0 to 908. Practical implications -The new horizon has been opened combining the rapid prototyping equipment in electronics and mechanical engineering in an interdisciplinary way to manufacture, for the first time, variable capacitor using poly-jet and ink-jet technologies. These techniques do not require higher mask counts which makes the fabrication fast and cost-effective. Originality/value -This work, for the first time, demonstrates the combination of ALARIS 30 3D printer and Dimatix DMP-3000 materials deposition printer in order to fabricate the interdigital capacitor with complex 3D geometry. ALARIS 3D printer has been used for manufacturing plastic platform (with the possibility to precisely adjust angular position of one comb related to another) and Dimatix printer has been used to print silver conductive inks on flexible substrates (Kapton film), and this mechanically flexible structure was used to cover capacitor's fingers on the platform (assembly).

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Section: Introductionmentioning

confidence: 99%

Combining rapid prototyping techniques in mechanical engineering and electronics for realization of a variable capacitor

Stojanović

Mandić²,

Ćurčić³

et al. 2014

Rapid Prototyping Journal

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“…A RF varactor for 7.8 GHz VCO application was developed by Heves et al (2008). Huang et al (2009) developed a dual-electrode varactor for RF applications using Al/Cr. Elshurafa and El-Masry (2010) developed MEMS parallel-plate variable capacitors with customizable tuning range.…”

Section: Introductionmentioning

confidence: 99%

A top-down design methodology of MEMS varactor for RF applications based on a substrate-induced capacitive model

2011

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Due to their excellent quality factor in microwave frequency range, microelectromechanical (MEMS) varactors are an attractive choice for wireless communication engineers for building high performance telecommunication circuits. Significant progress in the technology of MEMS varactor has been reported over the past few years; however a comprehensive design methodology for the varactors based on some performance specifications is not reported. Also, it has been found that for the varactors fabricated with multi user processes (MUMPs), the measured capacitance deviates widely from the predicted value. In this work, it has been shown that a substrateinduced capacitance can change the expected capacitance of the varactor widely and can justify the deviation of the measured values to a good degree of accuracy. Here, a quantitative account of this difference has been presented. The capacitance profile of the varactor fabricated in PolyMUMPs process has been measured and the results show good agreement with the design values; thus indicating a clear influence of substrate induced capacitance on the varactor. Finally, a systematic design methodology of the varactor for a voltage controlled oscillator (VCO) application has been given.

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Surface Micromachining

Franssila

2010

Introduction to Microfabrication

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Development of a wide-tuning range and high Q variable capacitor using metal-based surface micromachining process

Cited by 7 publications

References 24 publications

Combining rapid prototyping techniques in mechanical engineering and electronics for realization of a variable capacitor

Combining rapid prototyping techniques in mechanical engineering and electronics for realization of a variable capacitor

A top-down design methodology of MEMS varactor for RF applications based on a substrate-induced capacitive model

Surface Micromachining

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