Discrete RF-power MIM BST thick-film varactors

Preis, Sebastian; Wiens, Alex; Kienemund, Daniel; Kendig, Dustin; Maune, Holger; Jakoby, Rolf; Heinrich, W.; Bengtsson, Olof

doi:10.1109/eumc.2015.7345919

Cited by 15 publications

(10 citation statements)

References 8 publications

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“…For saturation power, shown as red diamonds, the impedance variation is reduced slightly. Such behaviour was expected from earlier work [6]. The change of angle suggests a change of transmission phase inside the varactors.…”

supporting

confidence: 84%

“…BST power varactors: A BST composition of 60% Ba and 40% Sr with additional ZnO-B 2 O 3 for sintering temperature reduction is applied. A MIM configuration using a gear-rack like layout was chosen to distribute the heat induced inside the varactor over a larger volume [6]. Thick-film technology with a BST film thickness of 10 µm was chosen in order to achieve high breakdown voltage and linearity.…”

mentioning

confidence: 99%

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Reconfigurable package integrated 20 W RF power GaN HEMT with discrete thick‐film MIM BST varactors

et al. 2016

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A novel package integrated solution for gallium nitride high‐electron‐mobility transistors with an electronically two‐dimensional reconfigurable L‐section matching network is presented. Thick‐film barium‐strontium‐titanate (BST) varactors are used to realise a tunability of the load impedance of 1:2 in resistive and 1:1.5 in reactive parts, respectively, applying tuning voltages of up to 200 V. The tuneable module achieves a peak output power of 43.2 dBm (20.9 W). Comparison with simulated results using field simulations and a large‐signal model shows good agreement in terms of output power and power added efficiency and thus proves the concept of using metal–insulator–metal BST varactors for reconfigurability.

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supporting

confidence: 84%

mentioning

confidence: 99%

Reconfigurable package integrated 20 W RF power GaN HEMT with discrete thick‐film MIM BST varactors

et al. 2016

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“…Consequently, the capacitance of an interdigital (IDC) [6] or parallel plate (MIM) [10] capacitor is reduced linearly with the change in permittivity. The bulk ceramic form of BST suffers from thermal sensitivity but its dielectric constant is highest [11].…”

Section: Bst Mim Thick-film Varactor Designmentioning

confidence: 99%

“…This is the major limitation in resonance frequency for this type of devices. Thick-films can reduce thermal dependence and suppress piezoactivity but require a control voltage of several hundred volts, since the voltage is linearly dependent on the film thickness [10]. The ratio of Barium to Strontium, as well as addition of doping materials are used to control several properties of BST such as ε r , tunability, sintering temperature and dielectric losses.…”

Section: Bst Mim Thick-film Varactor Designmentioning

confidence: 99%

VSWR protection of power amplifiers using BST components

Ferretti

Preis

Heinrich

et al. 2016

2016 German Microwave Conference (GeMiC)

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A VSWR-protected ISM-band PA was realized using a BST based varactor for detuning of the input matching. Output VSWR levels of 30:1 can be tolerated by applying a varactor bias voltage of up to 20 V. The PA delivers 47.4 dBm output power at a maximum PAE of 49.5%. In case of high VSWR conditions the output power can be limited by detuning the varactor. It is shown that the concept protects the transistor efficiently with very low additional circuit complexity.

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“…BST as a tunable dielectric in varactors has been under investigation for several years now and shows promising results regarding Q -factor, tunability, tuning speed, and power handling capabilities. In comparison to state-of-the-art technologies, such as mechanically tuned vacuum capacitors or switchable capacitor banks, utilizing high-power pin diodes, BST-based varactors offer a significantly higher tuning speed and continuous tuning [5,6]. A disadvantage of BST-based varactors is the bias induced piezoelectricity in the ferroelectric layer, introducing a dipole moment.…”

Section: Introductionmentioning

confidence: 99%

Low loss, fully-printed, ferroelectric varactors for high-power impedance matching at low ISM band frequency

Kienemund

Bohn

Fink

et al. 2019

Int. J. Microw. Wireless Technol.

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Low loss, ferroelectric, fully-printed varactors for high-power matching applications are presented. Piezoelectric-induced acoustic resonances reduce the power handling capabilities of these varactors by lowering the Q-factor at the operational frequency of 13.56 MHz. Here, a quality factor of maximum 142 is achieved with an interference-based acoustic suppression approach utilizing double metal–insulator–metal structures. The varactors show a tunability of maximum 34% at 300 W of input power. At a power level of 1 kW, the acoustic suppression technique greatly reduces the dissipated power by 62% from 37 W of a previous design to 14.2 W. At this power level, the varactors remain tunable with maximum 18.2% and 200 V of biasing voltage.

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Discrete RF-power MIM BST thick-film varactors

Cited by 15 publications

References 8 publications

Reconfigurable package integrated 20 W RF power GaN HEMT with discrete thick‐film MIM BST varactors

Reconfigurable package integrated 20 W RF power GaN HEMT with discrete thick‐film MIM BST varactors

VSWR protection of power amplifiers using BST components

Low loss, fully-printed, ferroelectric varactors for high-power impedance matching at low ISM band frequency

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