Ferroelectric phase shifters for phased array radar applications

Collier, D.

doi:10.1109/isaf.1992.300662

Cited by 6 publications

(4 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By far the most convenient use of ferroelectrics is the room temperature operation of single crystal or polycrystalline materials. However, there have been only few reports of practical devices [61,62], for the reasons mentioned above.…”

Section: Phase Shiftersmentioning

confidence: 99%

Thin-film ferroelectric microwave devices

Lancaster

Powell

Porch

1998

Supercond. Sci. Technol.

218

113

View full text Add to dashboard Cite

When an electric field is applied to a ferroelectric material, the microwave permittivity undergoes a substantial change. This change in permittivity can be utilized in microwave devices to produce frequency-agile functions. This paper is a comprehensive review of the work on ferroelectric materials; this includes models of the ferroelectric permittivity and loss tangent, as well as methods of measurement of these properties. New measurements are presented on thin-film strontium titanate and single-crystal strontium barium titanate substrates. These results are compared with the model. A brief discussion is given of the applications of ferroelectric material in microwave devices.

show abstract

Section: Phase Shiftersmentioning

confidence: 99%

Thin-film ferroelectric microwave devices

Lancaster

Powell

Porch

1998

Supercond. Sci. Technol.

218

113

View full text Add to dashboard Cite

show abstract

“…Consequently, Ba 1Ϫx Sr x TiO 3 is widely used as a material for dielectric, pyroelectric and piezoelectric applications. [5][6][7][8][9] To optimize its properties, however, understanding its microstructural characteristics that may also be intermediate between those of BaTiO 3 and SrTiO 3 , would be helpful.…”

Section: Introductionmentioning

confidence: 99%

{111} Twin Formation and Abnormal Grain Growth in Barium Strontium Titanate

Lee

Jung

Kang

et al. 2003

Journal of the American Ceramic Society

View full text Add to dashboard Cite

Two series of experiments were performed to study the experimental conditions for the formation of {111} twins and related microstructures in barium strontium titanate ((Ba, Sr)TiO3). In the first series, the phase equilibria in the BaTiO3–SrTiO3–TiO2 system were determined. XRD and WDS analysis, done in the BaTiO3‐rich region, of 45(Ba,Sr)TiO3–10TiO2 samples annealed at 1250°C for 200 h in air showed that (Ba,Sr)TiO3 was in equilibrium with Ba6Ti17O40 (B6T17) and Ba4Ti13O30 phases with strontium solubility (Sr/(Ba + Sr)) of ∼0.02 and 0.20, respectively. In the second series the microstructures of samples consisting of a mixture of (Ba,Sr)TiO3 and 2.0 mol% TiO2, were observed after sintering at 1250°C for 100 h in air. {111} twins formed only in the samples with faceted B6T17 second phase particles, similar to the case of BaTiO3. In these samples, abnormal grain growth occurred in the presence of the {111} twins. In contrast, no {111} twins formed and no abnormal grain growth occurred in the samples containing second phase particles other than B6T17. With an increased substitution of strontium for barium, the aspect ratio of abnormal grains containing {111} twin lamellae was reduced. This result was attributed to a reduction in the relative stability of the {111} planes with the strontium substitution.

show abstract

“…1,2 Ultimately, these materials are envisioned to enter into microwave integrated circuits for a possible insertion in satellite and wireless communication platforms. 3,4 In this area, (Ba,Sr)TiO 3 -based ceramic thin films are considered as leading candidates for room temperature (RT) applications. 5,6 (Ba,Sr)-TiO 3 solid solutions exhibit a large permittivity that can be as large as 10 000 for bulk samples in the vicinity of the paraelectricto-ferroelectric phase transformation temperature T C , which can be controlled via the composition [e.g., the bulk T C of Ba 0.6 Sr 0.4-TiO 3 (BST) is close to RT (51C)].…”

Section: Introductionmentioning

confidence: 99%

Unusual Curie Point Independence of Thickness and Interfacial Properties for Perfectly (111)‐Oriented Ba_0.6Sr_0.4TiO₃ Thin Films

Yang

Wang

Dong

et al. 2010

Journal of the American Ceramic Society

View full text Add to dashboard Cite

This study investigated the variations in the permittivity with film thickness and measurement temperature of perfectly (111)‐oriented Ba0.6Sr0.4TiO3 thin films with thicknesses ranging from 45 to 800 nm, which were prepared by RF magnetron sputtering on Pt/TiOx/SiO2/Si substrates. All the films showed elongations in the lattice parameter, suggesting the presence of residual strains but which were insensitive to the film thickness. The temperature‐dependent measurement of the permittivity revealed an unusual Curie point independent of thickness, about 305±5 K, where the phase transition appeared frustrated. The thickness‐dependent permittivity at a given temperature was explained by using the interfacial intrinsic low‐permittivity layer model reported previously.

show abstract

Ferroelectric phase shifters for phased array radar applications

Cited by 6 publications

References 1 publication

Thin-film ferroelectric microwave devices

Thin-film ferroelectric microwave devices

{111} Twin Formation and Abnormal Grain Growth in Barium Strontium Titanate

Unusual Curie Point Independence of Thickness and Interfacial Properties for Perfectly (111)‐Oriented Ba_0.6Sr_0.4TiO₃ Thin Films

Contact Info

Product

Resources

About

Ferroelectric phase shifters for phased array radar applications

Cited by 6 publications

References 1 publication

Thin-film ferroelectric microwave devices

Thin-film ferroelectric microwave devices

{111} Twin Formation and Abnormal Grain Growth in Barium Strontium Titanate

Unusual Curie Point Independence of Thickness and Interfacial Properties for Perfectly (111)‐Oriented Ba0.6Sr0.4TiO3 Thin Films

Contact Info

Product

Resources

About

Unusual Curie Point Independence of Thickness and Interfacial Properties for Perfectly (111)‐Oriented Ba_0.6Sr_0.4TiO₃ Thin Films