A low-loss double-tuned transformer
November 1, 2007
Journal Article
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IEEE Microw. Wirel. Compon. Lett., Vol. 17, No. 11, November 2007, pp. 772-774.
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Summary
In this letter, we present a state-of-the-art, planar double-tuned transformer using high- , micromachined spiral inductors and integrated capacitors. This circuit provides a 4:1 impedance transformation over a 30% bandwidth centered at 4.06 GHz, with a minimum insertion loss of 1.50 dB. The fabricated circuit occupies a total area of 440 500 m2 and finds application in power amplifier and other matching applications. An accurate lumped-element circuit model and design tradeoffs are presented. We believe this is the first implementation of a planar microwave double-tuned transformer.