Accurate Extraction of Large Electromechanical Coupling in Piezoelectric MEMS Resonators

J. Microelectromech. Syst.

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et al. 2020

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In this work, we present a new paradigm for enabling gigahertz higher-order Lamb wave acoustic devices using complementarily oriented piezoelectric (COP) thin films. Acoustic characteristics are first theoretically explored with COP lithium niobate (LiNbO 3) thin films, showing their excellent frequency scalability, low loss, and high electromechanical coupling (k 2). Acoustic resonators and delay lines are then designed and implemented, targeting efficient excitation of higher-order Lamb waves with record-breaking low loss. The fabricated resonator shows a 2 nd-order symmetric (S2) resonance at 3.05 GHz with a high quality factor (Q) of 657, and a large k 2 of 21.5% and a 6 th-order symmetric (S6) resonance at 9.05 GHz with a high Q of 636 and a k 2 of 3.71%, both among the highest demonstrated for higher-order Lamb wave devices. The delay lines show an average insertion loss (IL) of 7.5 dB and the lowest reported propagation loss of 0.014 dB/µm at 4.4 GHz for S2. Notable acoustic passbands up to 15.1 GHz are identified. Upon further optimizations, the proposed COP platform can lead to gigahertz low-loss wideband acoustic components.

Section: A Complementarily Oriented Bi-layer Acoustic Resonatormentioning

confidence: 99%

“…A series inductance L s is included for modeling the IDT inductance in the measurement [50]. Following the recursive procedure in [71], the key parameters are extracted, listed in Table II, and also plotted in Fig. 7.…”

Section: A Complementarily Oriented Bi-layer Acoustic Resonatormentioning

confidence: 99%

Enabling Higher Order Lamb Wave Acoustic Devices With Complementarily Oriented Piezoelectric Thin Films

J. Microelectromech. Syst.

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et al. 2020

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“…To demonstrate transversal filters based on propagating acoustic waves, one need to operate beyond the cutoff by using larger β [32]. The phase velocity v p , group velocity v g , and K 2 at different β can be calculated by [38], [39]…”

Section: B A1 Acoustic Platform Selection and Analysismentioning

confidence: 99%

Low-Loss 5-GHz First-Order Antisymmetric Mode Acoustic Delay Lines in Thin-Film Lithium Niobate

IEEE Trans. Microwave Theory Techn.

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et al. 2021

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In this work, we present the low-loss acoustic delay lines (ADLs) at 5 GHz, using the first-order antisymmetric (A1) mode in 128 • Y-cut lithium niobate thin films. The ADLs use a single-phase unidirectional transducer (SPUDT) design with a feature size of quarter acoustic wavelength. The design space is analytically explored and experimentally validated. The fabricated miniature A1 ADLs with a feature size of 0.45 µm show a high operating frequency at 5.4 GHz, a minimum insertion loss (IL) of 3 dB, a fractional bandwidth (FBW) of 1.6%, and a small footprint of 0.0074 mm 2. The low IL and high operating frequency have significantly surpassed the state-of-theart performance of ADLs. The propagation characteristics of A1 acoustic waves have also been extracted. The demonstrated designs can lead to low-loss and high-frequency transversal filters for future 5G applications in the sub-6-GHz bands.

“…A multiresonance modified Butterworth-Van Dyke (MBVD) model, in which each resonance is captured by a motional branch of R m , L m , and C m , is used to interpret the measurement results [44], [54], [55]. As shown in Fig.…”

Section: B Admittance Responsementioning

confidence: 99%

10–60-GHz Electromechanical Resonators Using Thin-Film Lithium Niobate

IEEE Trans. Microwave Theory Techn.

Gao

et al. 2020

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This work presents a new class of microelectromechanical system (MEMS) resonator toward 60 GHz for the fifth-generation (5G) wireless communications. The wide range of the operating frequencies is achieved by resorting to different orders of the antisymmetric Lamb wave modes in a 400-nm-thick Z-cut lithium niobate thin film. The resonance of 55 GHz demonstrated in this work marks the highest operating frequency for piezoelectric electromechanical devices. The fabricated device shows an extracted mechanical Q of 340 and an f × Q product of 1.87 × 10 13 in a footprint of 2 × 10 −3 mm 2. The performance has shown the strong potential of LiNbO 3 antisymmetric mode devices for front-end applications in 5G high-band.