Millimeter-Wave Dielectric Properties of Highly Refractive Single Crystals Characterized by Waveguide Cavity Resonance

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

et al. 2020

We present the first group of GHz broadband SH0 mode acoustic delay lines (ADLs). The implemented ADLs adopt unidirectional transducer designs in a suspended X-cut lithium niobate thin film. The design space of the SH0 mode ADLs at GHz is first theoretically investigated, showing that the large coupling and sufficient spectral clearance to adjacent modes collectively enable the broadband performance of SH0 delay lines. The fabricated devices show 3-dB fractional bandwidth ranging from 4% to 34.3% insertion loss between 3.4 and 11.3 dB. Multiple delay lines have been demonstrated with center frequencies from 0.7 to 1.2 GHz, showing great frequency scalability. The propagation characteristics of SH0 in lithium niobate thin film are experimentally extracted. The demonstrated ADLs can potentially facilitate broadband signal processing applications.

Section: B Acoustic Delay Lines With Different Center Frequenciesmentioning

confidence: 96%

GHz Broadband SH0 Mode Lithium Niobate Acoustic Delay Lines

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

et al. 2020

“…The higher-order modes, within the same resonant body, present a declining Q at higher frequencies, from around 600 below 10 GHz (A1 to S6) to about 200 above 20 GHz (A13 to S16). The result that the higher-order Lamb waves show higher damping might be caused by a combination of more significant electrical [43] and mechanical [15] damping at higher frequencies.…”

Section: A Complementarily Oriented Bi-layer Acoustic Resonatormentioning

confidence: 99%

“…The promising performance arises from the simultaneously achieved k 2 as high as 30%, low damping, and fast phase velocity across the sub-6 GHz NR bands [38]- [41]. Fundamentally, the large piezoelectric coefficient d 15 [42], low acoustic loss, and EM loss tangent [15], [43] are the reasons for these advances. Leveraging the A1 mode in LiNbO 3 , both the resonant -e.g., resonators and filters [44]- [46] -and the non-resonant -e.g., acoustic delay lines (ADLs) [47] have been reported with record-breaking IL and FBW.…”

Section: Introductionmentioning

confidence: 99%

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

J. Microelectromech. Syst.

Link

et al. 2020

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.

“…The dielectric loss in LiNbO 3 is another source of the loss affecting the admittance at antiresonance [56]. The value of the loss tangent (tanδ) is referred to the previous measurements of the dielectric properties of the single-crystal lithium niobate [60]. However, the value of tanδ is not constant across the whole measured frequency range [61], which makes the fittings near the antiresonance not accurate for some modes.…”

Section: Quality Factormentioning

confidence: 99%

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

IEEE Trans. Microwave Theory Techn.

Gao

et al. 2020

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.