Discrete RF-Power MIM BST Thick-Film Varactors

S. Preis1, A. Wiens2, D. Kienemund2, D. Kendig3, H. Maune2, R. Jakoby2, W. Heinrich1, O. Bengtsson1

Published in:

Proc. 45th European Microwave Conf. (EuMC 2015), Paris, France, Sep. 7-10, pp. 941-944 (2015).

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Abstract:

Discrete high power RF varactors based on barium-strontium-titanate are presented in this paper. They are targeting high power applications up to 3 GHz and feature power handling capabilities up to 50 W as well as promising tunability, due to the novel metal-insulator-metal configuration. The varactors are fabricated on Al2O3 in screen-print thick-film technology and mounted in RF-power transistor packages. Capacitances in the range from 1.4 pF to 28 pF were designed. Small- and large-signal measurements show a maximum insertion loss of 0.3 dB to 0.5 dB and a tunability of 7% to 30% at 1/3 of the resonance frequency. The exceptional linearity of BST was verified using two-tone measurements, resulting in 65 dBm OIP3.

1 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
2 Institut fuer Mikrowellentechnik und Photonik, Technische Universitaet Darmstadt, Merckstrasse 25, 64283 Darmstadt, Germany
3 Microsanj LLC, 3287 Kifer Road, Santa Clara, CA 95051, USA

Keywords:

Ceramics, ferroelectrics, BST, tunable components, adaptive matching, non-linear devices, power amplifier.