Ferroelectric films: nonlinear properties and applications in microwave devices

AbstractÀThis paper describes the design and processing of ferroelectric parallel plate capacitors embedded within a low temperature cofired ceramics (LTCC) structure. A capacitor is fabricated by filling a via hole with ferroelectric paste. Using ferroelectric materials, low-loss barium strontium titanate (BST) and barium zirconate titanate (BZT), as dielectric materials provide a wide range of tunability, in addition to low loss and low production cost. In addition, embedding tunable capacitors (varactors) inside LTCC reduces loss, size, weight, and cost. The paper also gives a comparison between the use of BST and BZT as tunable dielectric materials embedded inside an LTCC with respect to preparation process, applied voltage, shrinking factors, and quality factors.

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“…The main value of ferroelectric materials is the strong dependence of their dielectric permittivity e on the applied bias voltages [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Tunable BaSrTiO3, BaZrTiO3 Ferroelectric Capacitors Embedded Inside Low Temperature Cofired Ceramics (LTCC)

Tork¹,

Elshabini²,

Barlow³

2013

Journal of Microelectronics and Electronic Packaging

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“…Lots of studies for tunability in microwave have been concentrated on Ba x Sr 1Àx O 3 (BST) materials which have demonstrated high tuning factors for relatively low static electric field amplitudes [5][6][7]. Because of the high stability and non volatility of their constituents, these ferroelectrics are easily fabricated by application of any of the available deposition techniques.…”

Section: Introductionmentioning

confidence: 99%

Ferroelectric-based agile devices—Application to tunable filters

Laur¹,

Rousseau²,

Tanné³

et al. 2007

Int J RF and Microwave Comp Aid Eng

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The development of multistandard devices requires the realization of tunable functions such as filters and phase-shifters. This led us to fabricate stubs and interdigital capacitors with ferroelectric materials so as to use them as basic circuits in loaded structures for further investigations about their behavior at microwave frequencies. This study was aimed at assessing topologies to find the one the most able to take benefit of the agility provided by the ferroelectric material.

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“…Several design options for BST phase shifters have been proposed (Kozyrev et al, 1998;Kim et al, 2002;Sherman et al, 2001;Kim et al, 2003;De Flaviis et al, 1997;Van Keuls et al, 1999). Reflection-type phase shifters consist of a 3-dB coupler and reflective loads (Kozyrev et al, 1998;Kim et al, 2002;Sherman et al, 2001 ). While wide bandwidths may be achieved with the reflection type topology, the coupler contributes directly to the insertion loss of the phase shifter, and requires a large portion of the die area.…”

Section: Ferroelectric Phase Shiftersmentioning

confidence: 99%

“…Nevertheless, they require high driving voltage (e.g., 40 V or higher), have low switching speed (> 10 µs), and suffer from reliability and packaging issues. Several design options for BST phase shifters have been proposed (Kozyrev et al, 1998;Kim et al, 2002;Sherman et al, 2001;Kim et al, 2003;De Flaviis et al, 1997;Van Keuls et al, 1999). Reflection-type phase shifters consist of a 3-dB coupler and reflective loads (Kozyrev et al, 1998;Kim et al, 2002;Sherman et al, 2001 ).…”

Section: Ferroelectric Phase Shiftersmentioning

confidence: 99%