Circularly Polarized Dielectric‐Loaded Antennas: Current Technology and Future Challenges

Mirsaneh, Mehdi; Leisten, O.P.; Zalinska, Beata; Reaney, Ian M.

doi:10.1002/adfm.200701444

Cited by 60 publications

(37 citation statements)

References 10 publications

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“…For many electronic device applications this limitation does not affect the utility of this technique, as many electrode systems and antennas [61,62] (as specific examples) demand connectivity throughout. Unlike many capillary action driven fabrication schemes, Method I makes it is possible to fill channels that are quite tortuous and include sharp turns, allowing for a geometrically diverse collection of possible pattern designs.…”

Section: Methods I: Mask Fabrication By Microfluidic Fillingmentioning

confidence: 99%

Fabrication of Flexible Binary Amplitude Masks for Patterning on Highly Curved Surfaces

Bowen

Nuzzo

2009

Adv Funct Materials

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This paper describes soft lithography methods that expand current fabrication capabilities by enabling high‐throughput patterning on nonplanar substrates. These techniques exploit optically dense elastomeric mask elements embedded in a transparent poly(dimethylsiloxane) (PDMS) matrix by vacuum‐assisted microfluidic patterning, UV–ozone‐mediated irreversible sealing, and chemical etching. These protocols provide highly flexible photomasks exhibiting either positive‐ or negative‐image contrasts, which serve as amplitude masks for large‐area photolithographic patterning on a variety of curved (and planar) surfaces. When patterning on cylindrical surfaces, the developed masks do not experience significant pattern distortions. For substrates with 3D curvatures/geometries, however, the PDMS mask must undergo relatively large strains in order to make conformal contact. The new methods described in this report provide planar masks that can be patterned to compliantly compensate for both the displacements and distortions of features that result from stretching the mask to span the 3D geometry. To demonstrate this, a distortion‐corrected grid pattern mask was fabricated and used in conjunction with a homemade inflation device to pattern an electrode mesh on a glass hemisphere with predictable registration and distortion compensation. The showcased mask fabrication processes are compatible with a broad range of substrates, illustrating the potential for development of complex lithographic patterns for a variety of applications in the realm of curved electronics (i.e., synthetic retinal implants and curved LED arrays) and wide field‐of‐view optics.

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Section: Methods I: Mask Fabrication By Microfluidic Fillingmentioning

confidence: 99%

Fabrication of Flexible Binary Amplitude Masks for Patterning on Highly Curved Surfaces

Bowen

Nuzzo

2009

Adv Funct Materials

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“…The recent rapid development of wireless communication coupled with the continued interest in miniaturization has expressed an increasing demand for discovery and development of microwave dielectric materials with optimum microwave properties [1][2][3][4][5][6][7]. For commercial application, three key merits are required for materials, that is, an appropriate dielectric constant (e r ), a high quality factor (Q 9 f) and a near zero temperature coefficient of resonant frequency (s f ).…”

Section: Introductionmentioning

confidence: 99%

Sintering behavior and microwave dielectric properties of LiMVO4 (M = Mg, Zn)

Wei

Luo

et al. 2015

J Mater Sci: Mater Electron

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Two V-containing microwave dielectric ceramics, LiMgVO 4 and LiZnVO 4 , with excellent microwave performance were prepared by a solid-state reaction route at relatively low temperatures. Using NH 4 VO 3 to replace V 2 O 5 could effectively reduce the sintering temperature of LiMgVO 4 and LiZnVO 4 to 720°C and enhance their microwave dielectric properties. LiMgVO 4 ceramics sintered at 720°C exhibited a permittivity *9.89, a Q 9 f value of 30,800 GHz and a temperature coefficient of resonant frequency *-171 ppm/°C. LiZnVO 4 ceramics had a relatively smaller s f value of -114 ppm/°C with a e r * 7.48, a Q 9 f value of 27,600 GHz. Further efforts are in progress to search for effective approaches to compensate their large negative s f values to be near zero.

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“…To meet the requirements of these applications, the materials should have high relative permittivity (e r ), high quality factor (Q 9 f) and near zero temperature coefficient of resonant frequency (s f ) [3,4].…”

Section: Introductionmentioning

confidence: 99%

Microstructure and microwave dielectric properties of BaNd2Ti4−xAl4x/3O12 ceramics

Chen

Kang

et al. 2016

J Mater Sci: Mater Electron

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Using the solid-state ceramic route, BaNd 2 Ti 4-x Al 4x/3 O 12 (0 B x B 0.15) ceramics were prepared, and the structure, microstructure, and microwave dielectric properties were investigated. The XRD results suggest the formation of single solid solution phase with orthorhombic structure for all studied compositions (0 B x B 0.15) and the unit cell volume decreases linearly with x. The SEM results also show no evidence of secondary phase. A small amount of substitutions improves quality factor (Q 9 f) and the temperature coefficient of resonant frequency (s f ) but leads to a decrease of the permittivity. The s f value is found to decrease with increasing substitutions because of the declination of tolerance factor (t). And the s f can be adjusted from 79.5 to 38.3 ppm/°C with increment of substitutions. Finally, excellent dielectric properties are achieved as x = 0.1 sintered at 1320°C for 4 h in air: e r = 86.1, Q 9 f = 9702 GHz, s f = 43.1 ppm/°C. The Q 9 f value is strongly affected by the annealing process. The samples annealed at 1100°C for 15 h exhibit the best microwave dielectric properties.

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Circularly Polarized Dielectric‐Loaded Antennas: Current Technology and Future Challenges

Cited by 60 publications

References 10 publications

Fabrication of Flexible Binary Amplitude Masks for Patterning on Highly Curved Surfaces

Fabrication of Flexible Binary Amplitude Masks for Patterning on Highly Curved Surfaces

Sintering behavior and microwave dielectric properties of LiMVO4 (M = Mg, Zn)

Microstructure and microwave dielectric properties of BaNd2Ti4−xAl4x/3O12 ceramics

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