A miniaturized SAW reflector filter for IF stage of CDMA cellular phone applications

Yamada, Takahiro; Nakamura, Hiroyuki; Tsuzuki, S.; Ishizaki, T.; Ogawa, Kiyohisa

doi:10.1109/ultsym.1999.849429

Cited by 5 publications

(5 citation statements)

References 7 publications

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“…This indicates that without an improvement in the line width resolution limit technology of the IDTs the use of diamond based structures can realize the SAW devices with width-modulated configurations, such as single phase unidirectional transducers (SPUDTs) and width-controlled reflectors, which are applicable for double mode SAW (DMS) filters, two-track SAW filters, ladder filters, resonators, and sensors. [10][11][12] In this study, we attempt to design the two-track SAW filter with width-weighted reflectors in the (100) AlN/diamond structure. Cu IDT is applied due to its reflectivity is two times larger than conventional Al IDT.…”

Section: Introductionmentioning

confidence: 99%

Design of IF Two-Track Surface Acoustic Wave Filters Using (100) AlN/Diamond Structures

Sung

Lee

et al. 2010

IUTAM Symposium on Recent Advances of Acoustic Waves in Solids

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Abstract. In this paper, characteristics of two-track surface acoustic wave (SAW) filters based on Cu electrode/(100) AlN/diamond structures were analyzed using the finite element method (FEM) and the transmission matrix method. To achieve optimum performance, the Chebyshev window function was used to modify the reflectivity distributions of reflectors. The SAW parameters for weighted reflectors with various electrode thicknesses and different metallization ratios are retrieved using the FEM. The transmission matrix method was then employed to calculate the scattering parameters of weighted reflectors and two-track SAW filters. Simulation results show a two-track SAW filter with low insertion loss, good shape factor, good sidelobe suppression, small group delay, and flat passband can be tailored and applicable to the code division multiple access (CDMA) system.

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Section: Introductionmentioning

confidence: 99%

Design of IF Two-Track Surface Acoustic Wave Filters Using (100) AlN/Diamond Structures

Sung

Lee

et al. 2010

IUTAM Symposium on Recent Advances of Acoustic Waves in Solids

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“…Another popular IF filter configuration is the two-track SAW filter. [8][9][10] This filter can be applied to wireless communications in a CDMA system because of its low insertion loss, high sidelobe suppression and flat-passband ripples. 10) A two-track SAW filter consists of two-track input and output interdigital transducers (IDTs) that are connected in parallel.…”

Section: Introductionmentioning

confidence: 99%

“…The filter is essentially a SFIT with a two-track configuration. In two-track SAW filters, [8][9][10] reflectors are employed to attain the desired frequency responses with a flat passband and good sidelobe suppression. From our simulation results, 10) the 3 dB fractional bandwidth that can be achieved using reflectors is approximately 1-2%, which is much less than our desired bandwidth.…”

Section: Introductionmentioning

confidence: 99%

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Frequency Responses of Surface-Acoustic-Wave Filters with Two-Track Slanted Finger Interdigital Transducers

Tung¹,

Ro²

2005

Jpn. J. Appl. Phys.

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In this study, the scattering characteristics of a novel surface-acoustic-wave (SAW) filter with two-track slanted finger interdigital transducers (SFITs) are investigated. The novel SAW filter consists of two-track input and output SFITs, with each track configured in many subfilters in parallel connection. Because the arrival time of a SAW may differ among subfilters, passband ripples appear. However, by properly controlling the gap length between the input and output SFITs of each track, passband ripples can be eliminated evidently. Moreover, due to differences in radiation conductance among subfilters, a curve fitting technique is used to design the overlap width of each subfilter to maintain the passband responses of the SAW filter as flat as possible. A Chebyshev polynomial and a two-step weighting technique are employed to decrease sideband level. Simulation results show that by tailoring SAW SFITs and the gap difference of each track, a high-performance broadband IF filter can be obtained.

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“…SAW operating in the second mode in the (100) AlN/diamond structure exhibits high phase velocity 10780 m/s and relatively large electromechanical coupling coefficient (K 2 ) 2.4% [8]. The increase of phase velocity diminishes the line width limitation and, hence, improves the feasibility of SAW devices with width-modulated reflectors such as double mode SAW (DMS) filters, two-track SAW filters, and ladder filters [9][10][11].…”

mentioning

confidence: 99%

Design of IF two-track filters using IDT/(100) AlN/diamond structure

Lee

Sung

et al. 2009

2009 IEEE International Frequency Control Symposium Joint With the 22nd European Frequency and Time Forum

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Propagation characteristics of surface acoustic waves (SAWs) in IDT/(100) AlN/diamond structures are analyzed in this study using the finite element method (FEM). The extracted coupling-of-mode (COM) parameters are employed to calculate the frequency responses of two-track SAW filters using the transmission matrix method. To enhance the sideband suppression, Chebyshev function is adopted to modify the reflectivity distributions of reflectors, which can be realized using width-modulated reflectors. The copper electrode is used to retain a sufficiently high reflectivity. Simulation results show that a two-track SAW filter applicable for the CDMA system can be tailored using IDT/(100) AlN/diamond structures.

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A miniaturized SAW reflector filter for IF stage of CDMA cellular phone applications

Cited by 5 publications

References 7 publications

Design of IF Two-Track Surface Acoustic Wave Filters Using (100) AlN/Diamond Structures

Design of IF Two-Track Surface Acoustic Wave Filters Using (100) AlN/Diamond Structures

Frequency Responses of Surface-Acoustic-Wave Filters with Two-Track Slanted Finger Interdigital Transducers

Design of IF two-track filters using IDT/(100) AlN/diamond structure

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