A miniatuirized FBAR duplexer with reduced acoustic loss for the W-CDMA applicaion

Tsutsumi, J.; Iwaki, Masafumi; Iwamoto, Y.; Yokoyama, Tsuyoshi; Sakashita, Tatsuo; Nishihara, Tokihiro; Ueda, Masahiko; Satoh, Y.

doi:10.1109/ultsym.2005.1602804

Cited by 22 publications

(18 citation statements)

References 10 publications

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“…This out-band rejection is improved by 3 dB. This degradation is due to the length of bonding wire associating the active chip and PCB [10]. …”

Section: Co-design: Baw Filter-65nm Cmos Chipmentioning

confidence: 95%

“…The acoustical performance of the fully dielectric stack is comparable to the traditional SiO2-W reflectors; however, it strongly reduces the coupling between resonators through the Bragg reflector. Furthermore, the filter stack was realized on a high resistive silicon substrate in order to reduce losses due to the capacitive coupling [10].…”

Section: Ladder Baw-smr Filter Designmentioning

confidence: 99%

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Techniques for Tuning BAW-SMR Resonators for the 4th Generation of Mobile Communications

Hassan¹,

Kerhervé²,

Deval³

et al. 2013

Modeling and Measurement Methods for Acoustic Waves and for Acoustic Microdevices

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“…This out-band rejection is improved by 3 dB. This degradation is due to the length of bonding wire associating the active chip and PCB [10]. …”

Section: Co-design: Baw Filter-65nm Cmos Chipmentioning

confidence: 95%

Section: Ladder Baw-smr Filter Designmentioning

confidence: 99%

Techniques for Tuning BAW-SMR Resonators for the 4th Generation of Mobile Communications

Hassan¹,

Kerhervé²,

Deval³

et al. 2013

Modeling and Measurement Methods for Acoustic Waves and for Acoustic Microdevices

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“…The two filter dies and matching components were mounted on an approximately 3 x 3 mm laminated board. The compactness compares to the smallest duplexers reported so far [3][4][5]. The phase adjustment block was implemented by changing the length of the transmission line at the Rx port and adding lumped elements on the duplexer board.…”

Section: Principle Of Super-isolation Duplexermentioning

confidence: 99%

Super-Isolation Duplexer Aiming for Removing Rx Inter-stage Filter in W-CDMA Handsets

Tsutsumi

Matsumoto

2008

2008 38th European Microwave Conference

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A significant improvement in the Tx to Rx isolation of an antenna duplexer intended to remove the need for the Rx interstage filter in CDMA handsets is presented. A developed prototype of the W-CDMA (Band Class I) duplexer achieves 70 dB of isolation in the Tx band, while the isolation of conventional miniaturized duplexers is limited to about 50 dB. The developed "super-isolation duplexer" helps to remove the need for the Rx interstage filter, because the leakage signal from the transmitter, which is the largest interferer for the receiver, is mostly suppressed by the duplexer. I. INTRODUCTIONMiniaturized duplexers using surface acoustic wave (SAW) or film bulk acoustic wave resonator (FBAR) technology have greatly contributed to reduce the size of mobile phone handsets while maintaining good communication quality [1,2]. One of the most significant characteristics of duplexers is the Tx to Rx isolation in the Tx band which determines the leakage power from the transmitter (Tx leakage) to the receiver, because the Tx leakage is the largest interferer for the receiver. Conventional SAW or FBAR duplexers used in mobile handsets have an isolation of about 50 dB. The isolation is insufficient for the receiver to satisfy the system specification, so an off-chip Rx interstage filter is usually used in existing RF blocks for CDMA systems to suppress an unwanted leakage from the transmitter.There are strong requirements to reduce the number of components used in the RF block, because most current handsets support multiple bands/systems in one mobile phone. Therefore, the RF block for each band/system must be as simple and compact as possible. One way to simplify the RF block is to remove an off-chip Rx inter-stage filter. To realize such a simple RF block, it is necessary to reduce the Tx leakage to the receiver. We investigated how to improve the Tx to Rx isolation of the duplexer significantly, for example up to 70 dB, to reduce the Tx leakage to the receiver. We call such a highly isolated duplexer a "super-isolation duplexer".In this paper, the isolation of a duplexer is investigated thoroughly and an innovative methodology to improve the isolation is developed. Three-dimensional electromagnetic simulations are performed and a super-isolation duplexer for the W-CDMA Band Class I is demonstrated. A prototype of the super-isolation duplexer is developed, and its feasibility is demonstrated by the experimental results, where the isolation is significantly improved.

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“…As BAW resonator shows low vertical acoustic leakage due to air-gap structure or alternating acoustic mirror stacks implemented underneath the resonator, it performs lower losses and higher Q-factors than surface acoustic wave (SAW) resonators. Although BAW resonators utilize longitudinal acoustic waves, lateral acoustic waves are also generated in a large amount especially during anti-resonance [4,5,6,7]. Suppression of this lateral acoustic wave leakage is important for its antiresonance performances such as Q a and kt 2 .…”

Section: Introductionmentioning

confidence: 99%

Bulk acoustic wave resonator with suppressed energy loss using improved lateral structure

Shin

Song

Lee

et al. 2014

IEICE Electron. Express

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A bulk acoustic wave (BAW) resonator with suppressed energy loss is proposed. Implemented with air edge reflector and current spreading electrode along the perimeter region of the BAW, the resonator successfully suppresses the acoustic wave leakage and the electric energy loss as well. As results of optimized lateral structure, the Q-factor at anti-resonance frequency (Q a ) is significantly improved to over 2100. Furthermore, the peak insertion loss exhibits as low as 0.04 dB and effective electro-mechanical coupling coefficient (kt 2 ), which is essential to achieve wide band-width of RF filters, is 6.54%.

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A miniatuirized FBAR duplexer with reduced acoustic loss for the W-CDMA applicaion

Cited by 22 publications

References 10 publications

Techniques for Tuning BAW-SMR Resonators for the 4th Generation of Mobile Communications

Techniques for Tuning BAW-SMR Resonators for the 4th Generation of Mobile Communications

Super-Isolation Duplexer Aiming for Removing Rx Inter-stage Filter in W-CDMA Handsets

Bulk acoustic wave resonator with suppressed energy loss using improved lateral structure

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