A very small dielectric planar filter for portable telephones

Ishizaki, Toshio; Fujita, Masaru; Kagata, Hiroshi; Uwano, Tomoki; Miyake, Hideaki

doi:10.1109/22.330112

Cited by 130 publications

(32 citation statements)

References 6 publications

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“…However, since the conventional dielectric materials have high sintering temperatures [3], they would increase the manufacturing cost or would be difficult to be applied for co-firing. In contrast, Bi-based pyrochlores, Bi 2 O 3 -MO-Nb 2 O 5 (M: Mg, Zn, Ni, etc.…”

Section: Introductionmentioning

confidence: 99%

Low temperature synthesis of the microwave dielectric Bi2O3–MgO–Nb2O5 nano powders by metal-citrate method

Shim¹,

Yoon²,

Shim³

et al. 2006

Journal of Alloys and Compounds

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The microwave dielectric (Bi 1.5 Mg 0.5 )(Mg 0.5 Nb 1.5 )O 7 (BMN) nano powders were synthesized by metal-citrate process and their sintering behaviors were evaluated. The single phase of cubic pyrochlore was achieved at a low temperature of 600 • C for 3 h, together with the complete decomposition of the residual organic compounds. Increasing the heating temperature led to particle growth, indicating that the crystallite size of the powders synthesized at 600 • C was 16 nm, which increased to 34 nm on heating at 700 • C and 45 nm on heating at 800 • C, respectively. The BMN nano powders obtained at 600 • C could be fully densified at a low temperature of 850 • C by spark plasma sintering (SPS), showing the uniform microstructure.

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Section: Introductionmentioning

confidence: 99%

Low temperature synthesis of the microwave dielectric Bi2O3–MgO–Nb2O5 nano powders by metal-citrate method

Shim¹,

Yoon²,

Shim³

et al. 2006

Journal of Alloys and Compounds

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“…RF devices using LTCCs (low temperature cofired ceramics) are increasingly being used in mobile communications equipment [1]. However, the temperature coefficients of the resonance frequency (TCF) of many LTCC materials composed of Al 2 O 3 -glass systems show large negative values of around −50 ppm/K, since Al 2 O 3 has a negative TCF.…”

Section: Introductionmentioning

confidence: 99%

Al2O3-MgO-ReOx (Re: Rare Earth)-Based LTCC and its Application to Multilayer Non-Shrinkage Substrate for Microwave Devices

2004

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We studied the dielectric properties of Al 2 O 3 -MgO-ReO x (Re: rare earth) systems in the microwave region and found that the magnetoplumbite phases in the MgO-poor regions of MgReAl 11 O 19 (Re: La ∼ Tb) compositions had positive TCF (temperature coefficient of resonance frequency) values in spite of having low dielectric constants of under 20. By mixing a lead-free glass with the above system, a novel LTCC (which we term an AMSG) was obtained that was characterized by a low dielectric constant (<10), a near zero TCF, and high bending strength. When firing these AMSG green sheets inserted between HTCC alumina or magnesia green sheets that cannot be sintered at the AMSG sintering temperature, the AMSG sheets were seen to shrink not in the x-y directions but in the z direction due to the constraining effects of the HTCC layers. The obtained non-shrinkage substrate had precise dimensions and a high degree of flatness. The AMSG and the non-shrinking techniques have potential for application to integrated RF modules in mobile communications equipment.

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“…The rapidly growing microwave telecommunication devices demand the miniaturization of the size and weight, and the temperature stability of devices [1]. Thus many researchers devoted to develop the dielectric materials with a high dielectric constant (ε r ), a high quality value (Q) and a small temperature coefficient of resonant frequency ( f ).…”

Section: Introductionmentioning

confidence: 99%