隨著5G通訊標準對傳輸速率與物聯網應用的蓬勃發展，用於射頻(RF)訊號處理的聲波元件也面臨日益嚴峻的頻寬需求與大機電耦合係數(k_eff^2)的挑戰。本研究提出基於單晶薄膜鋰鈮酸鹽(LN)實現之高性能表面聲波(SAW)元件，此類元件係利用異質聲波波導設計來有效達成一般表面聲波元件難以觸及之高機電耦合係數與相關應用。首先是以絕緣層上覆單晶鋰鈮酸鋰薄膜平台(LNOI)為例，研究水平剪切表面聲波(SH-SAW)在此類異質聲波波導架構下的頻散、溫度穩定性及其他性能指標。文中也討論了SH-SAW共振器在此類異質聲波波導架構下適合的指叉式電極換能器設計與性能分析，結果顯示，LNOI SH-SAW原型元件在各種性能指標中(包括機電耦合係數、品質因數(Q)和頻率溫度係數(TCF))均具有相當優異的表現，因此，本研究所提出之異質聲波波導與元件具有相當優異的優質(Figure of Merit，FoM)，定義為機電耦合係數與品質因數之乘積，故後續亦基於高FoM元件之實際量測數據，評估以LNOI SH-SAW設計的GHz寬頻濾波器，其結果顯示此平台具有良好的應用潛力。
隨後本研究進一步探索基於金電極實現的高FoM LNOI SH-SAW共振器的設計。雖然金通常被認為是一種不利於高品質因數的電極材料，但本研究中透過適當的電極設計成功實現具有優異機電耦合係數與高品質因數之SH-SAW共振器，其性能可與其他電極材料相媲美。為了進一步推進濾波器應用所需之無漣波帶通響應，本研究提出新穎表面聲波元件設計用以解決基於異質聲波波導架構下常見的雷利波雜散模態與橫向雜散模態問題。首先是提出利用聲波頻散特性設計之SH-SAW共振器以解決雷利波雜散模態，後續亦提出可抑制橫向雜散模態之“超短聲學孔徑”共振器設計。隨後以基於本研究中所設計和製造的SH-SAW共振器實際展示此類元件用於對雜散模敏感的被動阻抗匹配應用下可預期的優異性能與前景。
最後，本研究亦透過將表面聲波元件的應用延展至超高頻段探索此類元件在下一代無線標準(6G)中的應用。為了將表面聲波元件用於更高的操作頻率，本文提出了如碳化矽（SiC）晶圓上覆單晶鋰鈮酸薄膜等可提供更好的聲波約束能力之異質聲波波導設計。共振器原型成功將表面聲波元件操作於C波段(4-8 GHz)、厘米波段(7-14 GHz)和毫米波段(20 GHz以上)，其結果清晰的展現了表面聲波元件可借助異質聲波波導設計實現在相應頻段均具有與時下最先進的聲學解決方案相當或更優之性能，並藉此表明表面聲波元件在6G無線通信新時代中的強大潛力。
總結來說，本研究中所提出之各式異質聲波波導所設計的表面聲波共振器，其性能可依操作頻率大致分類歸納為：基於金電極與絕緣層上覆單晶鋰鈮酸鋰薄膜平台所實現之水平剪切模態表面聲波共振器具有在2 GHz以下高於450之優質，其大約是由45%之機電耦合係數與1000之品質因數所組成；基於鋁電極與碳化矽晶圓上覆單晶鋰鈮酸薄膜所實現之C波段水平剪切模態表面聲波共振器則具有約100之優質，由20%以上之機電耦合係數與500之品質因數所組成；操作於毫米波頻段之表面聲波共振器則具有約2-3%之機電耦合係數與約1-200之品質因數，與先進薄膜聲波共振器相仿更保有優異的可靠性與良好的散熱能力。

This work presents high performance surface acoustic wave (SAW) radio frequency (RF) devices based on thin film lithium niobate (LN) targeting the 5G wireless systems. To fulfill the need for ever increasing bandwidth and electromechanical coupling coefficients (k_eff^2). The LN-based hetero acoustic layered (HAL) waveguide is proposed exactly targeting high k_eff^2 applications. The LN on Insulator (LNOI) platform is used as an example to understand the dispersion, temperature stability and other performance characteristics unique to these HAL waveguide structure. The Shear Horizontal-SAW (SH-SAW) device design are also discussed based on this HAL stacking and the fabricated devices demonstrated excellent performance in various performance indices including k_eff^2, quality factor (Q) figure-of-merit (FoM=k_eff^2∙Q) and temperature coefficient of frequency (TCF). The GHz filter application potentials are then studied based on LNOI SH-SAW resonators with good FoM. To further explore the design of high FoM LNOI SH-SAW resonators, the electrode configuration is especially studied targeting gold electrodes. Gold is generally considered as a lossy material not suitable for acoustic applications. However, LNOI SH-SAW resonators with gold electrode are selected as an experimental case study to highlight the importance of SAW electrode design. The results indicate that with properly selected electrode configuration, it is possible to obtain high performance SH-SAW devices with superior performance on par with state-of-the-art works based on other electrode materials.
Novel SAW transducer designs are then proposed to resolve common issues found in acoustic devices based on HAL waveguides. This includes the dispersion engineering technique targeting the removal of Rayleigh spurious mode and the “ultra-short-aperture” design that can effectively suppress the transverse spurious modes. Spurious sensitive applications such as passive impedance transformers that benefit from using these techniques are also demonstrated based on the spectrum clean devices designed and fabricated in this work. The future pathway for SAW in the next generation wireless system is then explored by extending SAW operation into the super high frequency bands. To enable SAW in those frequency bands, novel HAL stacking such as LN on silicon carbide (SiC) is proposed to provide better acoustic confinement. Devices operating at C-band (4-8 GHz), cm bands (7-14 GHz) and mmWave bands (above 20 GHz) are demonstrated. The result demonstrated are either on-par or above current state-of-the-art solutions in the corresponding frequency bands which clearly indicates the strong potentials in SAW that can be carried on into the new era of 6G wireless communications.
In summary, the performance of HAL SAW devices achieved in this work can be categorized based on the operation frequency: an excellent FoM of over 450 can be obtained using gold electrodes in the LNOI waveguide in the sub-2 GHz range based on a k_eff^2 of over 45% and a Q of around 1000. In the C-band, a high FoM of about 100 is obtained using aluminum electrodes in the LN on SiC waveguide based on a k_eff^2 of over 20% and a Q of around 500. Lastly, mmWave SAW devices exhibits a k_eff^2 of 2-3% and a Q of around 1-200, which is competitive with current state-of-the-art thin-film acoustic solutions with much superior mechanical robustness and thermal dissipation capabilities.

LIST OF FIGURES v
LIST OF TABLES xiv
CHAPTER 1 1
INTRODUCTION 1
1.1 Wide Band Signal Processing with Acoustic Devices 1
1.2 Recent Work 3
1.3 Fundamentals of Piezoelectric Acoustic Devices 9
1.4 Solid Mounted Thin Film LN Waveguide Structure 12
1.5 Dissertation Outline 13
CHAPTER 2: 15
Lithium Niobate on Insulator (LNOI) Platform and SH-SAW Resonators 15
2.1 The Lithium Niobate on Insulator (LNOI) platform 15
2.1.1 The LNOI Platform Overview 15
2.1.2 Acoustic Mode Selection 17
2.1.3 LNOI Hetero Acoustic Waveguide design 19
2.1.4 SH-SAW Propagation Direction Selection 22
2.2 SH-SAW Resonator Design and Simulation 23
2.2.1 Effects of IDT Electrode Materials 24
2.2.2 SH-SAW Resonator Design 31
2.3 Fabrication and Analysis on Measurement Results 32
2.3.1 Fabrication of the LNOI SH-SAW Devices 33
2.2.3 Design Summary and RF Measurement Setup 36
2.4 Prototype LNOI SH-SAW Measurement Results 38
2.4.1 SH-SAW with Different Wavelengths 38
2.4.2 Resonator Parameter Extraction 41
2.4.3 Effect of IDT electrode number (Ne) 42
2.4.4 Effect of Different Insulator SiO2 Thickness 44
2.5 Discussions on Q and k_eff^2 45
2.5.1 Quality Factor (Q) 45
2.5.2 Electromechanical Coupling Coefficient (k_eff^2) 46
2.6 Temperature Stability of LNOI SH-SAW Resonators 49
2.6.1 The Intrinsic Temperature Compensation of LNOI 51
2.6.2 TCF Simulation and the Effect of Rayleigh Spurious Mode Coupling 52
2.6.3 Temperature Stability Measurement 55
2.6.4 TCF Performance Comparison 57
2.7 Numerical Synthesized LNOI Filter 58
2.7.1 Resonator Used to Construct the Synthesis Filter 59
2.7.2 Synthesis Filter Performance and Discussions 60
2.8 Summary and Performance Comparisons 61
2.9 Comparison between Different Substrate Materials 66
CHAPTER 3 69
Surface Metallization in LNOI SH-SAW: Gold as the Electrode Material 69
3.1 Introduction 69
3.2 Acoustic Dispersions by Surface Metallization 71
3.3 Performance of LNOI SH-SAW Resonators with Gold Electrodes 75
3.3.1 LNOI SH-SAW Wavelength Scaling with Gold Electrodes 76
3.3.2 LNOI SH-SAW Electrode Thickness Modulation with Gold Electrodes 78
3.4 Temperature Stability Modulation Based on Gold Electrodes 80
3.5 Summary 83
CHAPTER 4 85
Dispersion Engineering for Rayleigh Spurious Mode Suppression 85
4.1 Numerical Analysis of the Dispersion Engineering Technique 86
4.1.1 The YX-LNOI Thin Film Waveguide 86
4.1.2 Mode Coupling Between the Two Modes 88
4.2 Spurious Suppression from Acoustic Dispersion Study 92
4.3 Experimental Validation of the Rayleigh Spurious Mode Suppression 94
4.4 Additional Applicable Stackings and Frequency Scaling Opportunities 99
4.5 Summary 100
CHAPTER 5 102
Spectrum Clean SH-SAW Resonator and Transverse Spurious Suppression 102
5.1 Active Aperture Design and Transverse Mode Suppression 103
5.2 “Ultra-short-aperture” LNOI SH-SAW Resonators 107
5.3 Characterization of “Ultra-short-aperture” SH-SAW Devices 111
5.4 High Performance SAW-based Impedance Transformers 114
5.5 Passive Gain Extraction for GHz SAW Impedance Transformers 116
5.6 Summary 122
CHAPTER 6 124
Toward 6G Centimeter(cm) Band SAW Devices 124
6.1 6th Generation (6G) Wireless and the cm Bands 124
6.2 C-band LN on Silicon Carbide SH-SAW Resonators 127
6.2.1 Design of C-band LN/Silicon Carbide (SiC) SH-SAW Resonators 128
6.2.2 Measured Admittance Characterization 130
6.2.3 Power Handling Performance Extraction 132
6.2.4 Discussion 134
6.3 Scaling the LNOI SH-SAW for 6G cm Bands 135
6.3.1 cm Band LNOI SH-SAW Resonator Design 135
6.3.2 Measured Result for LNOI cm Band SH-SAW 138
6.3.3 Discussion 140
6.4 Deploying SAW Devices Targeting mmWave Applications 141
6.4.1 A 22.4 GHz LSAW Resonator for mmWave Applications 142
6.4.2 A 23.44 GHz EG SH-SAW Resonator for mmWave Applications 144
6.4.3 Discussion 147
6.5 Summary 148
CHAPTER 7 150
CONCLUSION AND FUTURE WORK 150
7.1 Achievements 150
7.2 Future Research Directions 152
7.2.1 Loss Factor Study on SHF Devices 153
7.2.2 Materialization of a cm-band SH-SAW Filter 154
7.3 Concluding remarks 156
BIBLIOGRAPHY 157
PUBLICATION LIST 172
A. Submitted Journal Paper (1st author: 1) 172
B. Journal Publication (1st author: 6, Total publications: 11) 172
C. International Conference Proceedings (1st author: 10, Total publications: 27) 174

[1] B. O. hAnnaidh et al., “Devices and Sensors Applicable to 5G System Implementations,” in Proc., IEEE MTT-S Int. Microw. Workshop Ser. on 5G Hardware and Syst. Technologies (IMWS-5G’18), Dublin, Ireland, pp. 1-3, 2018.
[2] W. Ejaz, and M. Ibnkahla, “Multiband Spectrum Sensing and Resource Allocation for IoT in Cognitive 5G Networks,” IEEE Internet Things J., vol. 5, no. 1, pp. 150-163, 2018.
[3] “5G’s impact on RF front-end industry Trends 2017 report,” 2017; (Avalible at: http://www.yole.fr.)
[4] E. Dahlman et al., “5G wireless access: requirements and realization,” IEEE Commun. Mag., vol. 52, no. 12, pp. 42-47, 2014.
[5] J. J. Nielsen et al., “Ultra-Reliable Low Latency Communication Using Interface Diversity,” IEEE Trans. Commun., vol. 66, no. 3, pp. 1322-1334, 2018.
[6] J. Gubbi et al., “Internet of Things (IoT): A vision, architectural elements, and future directions,” Future Gener. Comput. Syst., vol. 29, no. 7, pp. 1645-1660, 2013.
[7] E. Hossain et al., “Evolution toward 5G multi-tier cellular wireless networks: An interference management perspective,” IEEE Wireless Commun., vol. 21, no. 3, pp. 118-127, 2014.
[8] R. Aigner et al., “BAW Filters for 5G Bands,” in Proc., IEEE Int. Electron Devices Mtg. (IEDM’18), 2018, pp. 14.5.1-14.5.4.
[9] E. G. Larsson et al., “Massive MIMO for next generation wireless systems,” IEEE Commun. Mag., vol. 52, no. 2, pp. 186-195, 2014.
[10] D. Bharadia et al., “Full duplex radios,” SIGCOMM Comput. Commun. Rev., vol. 43, no. 4, pp. 375–386, 2013.
[11] D. P. Morgan, Surface Acoustic Wave Filters: With Applications to Electronic Communications and Signal Processing: Academic Press, 2007.
[12] H. Bhugra, and G. Piazza, Piezoelectric MEMS Resonators: Springer International Publishing, 2017.
[13] P. Warder, and A. Link, “Golden Age for Filter Design: Innovative and Proven Approaches for Acoustic Filter, Duplexer, and Multiplexer Design,” IEEE Microwave Mag., vol. 16, no. 7, pp. 60-72, 2015.
[14] L. Rayleigh, “On Waves Propagated along the Plane Surface of an Elastic Solid,” Proc. London Math. Soc., vol. s1-17, no. 1, pp. 4-11, 1885.
[15] R. M. White, and F. W. Voltmer, “DIRECT PIEZOELECTRIC COUPLING TO SURFACE ELASTIC WAVES,” Appl. Phys. Lett., vol. 7, no. 12, pp. 314-316, 1965.
[16] R. H. Tancrell, and M. G. Holland, “Acoustic surface wave filters,” Proc. IEEE, vol. 59, no. 3, pp. 393-409, 1971.
[17] C. C. W. Ruppel, “Acoustic Wave Filter Technology–A Review,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 64, no. 9, pp. 1390-1400, 2017.
[18] K. Hashimoto, Surface acoustic wave devices in telecommunications. Modelling and simulation, 2000.
[19] K. Hashimoto, RF Bulk Acoustic Wave Filters for Communications: Artech, 2009.
[20] Q. Zou et al., “Temperature-compensated FBAR duplexer for band 13,” in Proc., IEEE Int. Ultrason. Symp. (IUS’13), pp. 236-238, 2013.
[21] S. Marksteiner et al., “Optimization of acoustic mirrors for solidly mounted BAW resonators,” in Proc., IEEE Int. Ultrason. Symp. (IUS’05), pp. 329-332, 2005.
[22] W. E. Newell, “Face-mounted piezoelectric resonators,” Proc. IEEE, vol. 53, no. 6, pp. 575-581, 1965.
[23] R. Ruby, “A snapshot in time: The future in filters for cell phones,” IEEE Microwave Mag., vol. 16, no. 7, pp. 46-59, 2015.
[24] M. Park et al., “Epitaxial Aluminum Scandium Nitride Super High Frequency Acoustic Resonators,” J. Microelectromech. Syst., vol. 29, no. 4, pp. 490-498, 2020.
[25] S. Gong et al., “Microwave Acoustic Devices: Recent Advances and Outlook,” IEEE J. Microwaves, vol. 1, no. 2, pp. 601-609, 2021.
[26] J. Bjurström et al., “Lateral-field-excited thin-film Lamb wave resonator,” Appl. Phys. Lett., vol. 86, no. 15, pp. 154103, 2005.
[27] G. Piazza et al., “Piezoelectric Aluminum Nitride Vibrating Contour-Mode MEMS Resonators,” J. Microelectromech. Syst., vol. 15, no. 6, pp. 1406-1418, 2006.
[28] C. M. Lin et al., “Micromachined One-Port Aluminum Nitride Lamb Wave Resonators Utilizing the Lowest-Order Symmetric Mode,” J. Microelectromech. Syst., vol. 23, no. 1, pp. 78-91, 2014.
[29] J. Zou et al., “The Multi-Mode Resonance in AlN Lamb Wave Resonators,” J. Microelectromech. Syst., vol. 27, no. 6, pp. 973-984, 2018.
[30] J. Wang et al., “A Film Bulk Acoustic Resonator Based on Ferroelectric Aluminum Scandium Nitride Films,” J. Microelectromech. Syst., vol. 29, no. 5, pp. 741-747, 2020.
[31] L. Colombo et al., “Investigation of 20% scandium-doped aluminum nitride films for MEMS laterally vibrating resonators,” in Proc., IEEE Int. Ultrason. Symp. (IUS’17), pp. 1-4, 2017.
[32] G. Pillai et al., “Design and Optimization of SHF Composite FBAR Resonators,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 64, no. 12, pp. 1864-1873, 2017.
[33] C. Tu, and J. E. Y. Lee, “VHF-band biconvex AlN-on-silicon micromechanical resonators with enhanced quality factor and suppressed spurious modes,” J. Micromech. Microeng., vol. 26, no. 6, pp. 065012, 2016.
[34] G. Chen et al., “Lithographically defined aluminum nitride cross-sectional Lamé mode resonators,” J. Micromech. Microeng., vol. 27, no. 3, pp. 034003, 2017.
[35] Qualcomm, “Global update on spectrum for 4G & 5G,” 2020; (Avalible at: www.qualcomm.com.)
[36] J. Kramer et al., “Trilayer Periodically Poled Piezoelectric Film Lithium Niobate Resonator,” in Proc., IEEE Int. Ultrason. Symp. (IUS’23), pp. 1-4, 2023.
[37] S. Inoue, and M. Solal, “Spurious Free SAW Resonators on Layered Substrate with Ultra-High Q, High Coupling and Small TCF,” in Proc., IEEE Int. Ultrason. Symp. (IUS’18), pp. 1-9, 2018.
[38] T. Takai et al., “I.H.P. SAW technology and its application to microacoustic components (Invited),” in Proc., IEEE Int. Ultrason. Symp. (IUS’17), pp. 1-8, 2017.
[39] T. Takai et al., “High-Performance SAW Resonator on New Multilayered Substrate Using LiTaO3 Crystal,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 64, no. 9, pp. 1382-1389, 2017.
[40] T. Takai et al., “High-Performance SAW Resonator With Simplified LiTaO3/SiO2 Double Layer Structure on Si Substrate,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 66, no. 5, pp. 1006-1013, 2019.
[41] Y. Chen et al., “Heterogeneous integration of lithium tantalate thin film on quartz for high performance surface acoustic wave resonator,” Jpn. J. Appl. Phys., vol. 62, no. 1, pp. 015503, 2023.
[42] J. Wu et al., “Exploring Low-Loss Surface Acoustic Wave Devices on Heterogeneous Substrates,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 69, no. 8, pp. 2579-2584, 2022.
[43] S. Wu et al., “High-performance SH-SAW resonator using optimized 30° YX-LiNbO3/SiO2/Si,” Appl. Phys. Lett., vol. 120, no. 24, 2022.
[44] X. He et al., “Single-crystalline LiNbO3 film based wideband SAW devices with spurious-free responses for future RF front-ends,” Appl. Phys. Lett., vol. 120, no. 11, pp. 113507, 2022.
[45] R. Su et al., “Over GHz bandwidth SAW filter based on 32° Y-X LN/SiO2/poly-Si/Si heterostructure with multilayer electrode modulation,” Appl. Phys. Lett., vol. 120, no. 25, pp. 253501, 2022.
[46] Y. Yang et al., “Surface-Acoustic-Wave Devices Based on Lithium Niobate and Amorphous Silicon Thin Films on a Silicon Substrate,” IEEE Trans. Microwave Theory Tech., vol. 70, no. 11, pp. 5185-5194, 2022.
[47] Y. Guo et al., “Investigation on the temperature coefficient of frequency performance of LiNbO3 on quartz and glass surface acoustic wave resonators,” Jpn. J. Appl. Phys., vol. 62, no. SJ, pp. SJ1024, 2023.
[48] S. Zhang et al., “Surface Acoustic Wave Resonators Using Lithium Niobate on Silicon Carbide Platform,” in Proc., IEEE MTT-S Int. Microw. Symp. (IMS’20), pp. 253-256, 2020.
[49] H. Xu et al., “SAW filters on LiNbO3/SiC heterostructure for 5G n77 and n78 band applications,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 70, no. 9, pp. 1157-1169, 2023.
[50] M. Kadota et al., “SAW substrate for Duplexer with Excellent Temperature Characteristics and Large Reflection Coefficient realized by using Flattened SiO2 Film and Thick Heavy Metal Film,” in Proc., IEEE MTT-S Int. Microw. Symp. (IMS’06), pp. 382-385, 2006.
[51] S. Tanaka et al., “Lithium-niobate-based surface acoustic wave oscillator directly integrated with CMOS sustaining amplifier,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 59, no. 8, pp. 1800-1805, 2012.
[52] F. G. Marshall et al., “Theory and Design of the Surface Acoustic Wave Multistrip Coupler,” IEEE Trans. Microwave Theory Tech., vol. 21, no. 4, pp. 206-215, 1973.
[53] W. R. Smith et al., “Design of Surface Wave Delay Lines with Interdigital Transducers,” IEEE Trans. Microwave Theory Tech., vol. 17, no. 11, pp. 865-873, 1969.
[54] A. Springer et al., “A wireless spread-spectrum communication system using SAW chirped delay lines,” IEEE Trans. Microwave Theory Tech., vol. 49, no. 4, pp. 754-760, 2001.
[55] H. Jaffe, and D. A. Berlincourt, “Piezoelectric transducer materials,” Proc. IEEE, vol. 53, no. 10, pp. 1372-1386, 1965.
[56] T. Ikeda, Fundamentals of Piezoelectricity: Oxford University Press, 1996.
[57] “IEEE standard on piezoelectricity, ” ANSI/IEEE Std 176-1987, 1988, p. 0_1.
[58] J. D. Larson et al., “Modified Butterworth-Van Dyke circuit for FBAR resonators and automated measurement system,” in Proc., IEEE Int. Ultrason. Symp. (IUS’00), pp. 863-868, 2000.
[59] R. Lu, and S. Gong, “Study of thermal nonlinearity in lithium niobate-based MEMS resonators,” in Proc., 18th Int. Conf. on Solid-State Sensors & Actuators (Transducers’15), pp. 1993-1996, 2015.
[60] P. Zheng et al., “Near 5-GHz longitudinal leaky surface acoustic wave devices on LiNbO3/SiC substrates,” IEEE Trans. Microwave Theory Tech., vol. 72, no. 3, pp. 1480-1488, 2024.
[61] T. H. Hsu et al., “Large coupling acoustic wave resonators based on LiNbO₃/SiO₂/Si functional substrate,” IEEE Electron Device Lett., vol. 41, no. 12, pp. 1825-1828, 2020.
[62] T. H. Hsu et al., “Wideband and high quality factor shear horizontal SAW resonators with improved temperature stability in LNOI platform,” in Proc., 2021 Joint Conf. of Eur. Freq. Time Forum - IEEE Int. Freq. Contr. Symp. (EFTF-IFCS’21), pp. 1-4, 2021.
[63] T.-H. Hsu et al., “Thin-film lithium niobate-on-insulator (LNOI) shear horizontal surface acoustic wave resonators,” J. Micromech. Microeng., vol. 31, no. 5, pp. 054003, 2021.
[64] C. Y. Chen et al., “Q-enhanced Lithium Niobate SH0 Resonators with Optimized Acoustic Boundaries,” in Proc., 2019 Joint Conf. of Eur. Freq. Time Forum - IEEE Int. Freq. Contr. Symp. (EFTF-IFCS’19), pp. 1-4, 2019.
[65] R. Lu et al., “A1 Resonators in 128° Y-cut Lithium Niobate with Electromechanical Coupling of 46.4%,” J. Microelectromech. Syst., vol. 29, no. 3, pp. 313-319, 2020.
[66] M. H. Li et al., “Temperature stability analysis of thin-film lithium niobate SH0 plate wave resonators,” J. Microelectromech. Syst., vol. 28, no. 5, pp. 799-809, 2019.
[67] S. Gong, and G. Piazza, “Design and Analysis of Lithium–Niobate-Based High Electromechanical Coupling RF-MEMS Resonators for Wideband Filtering,” IEEE Trans. Microwave Theory Tech., vol. 61, no. 1, pp. 403-414, 2013.
[68] M. Faizan, and L. G. Villanueva, “Frequency-scalable fabrication process flow for lithium niobate based Lamb wave resonators,” J. Micromech. Microeng., vol. 30, no. 1, pp. 015008, 2020.
[69] L. Colombo et al., “X-Cut Lithium Niobate Laterally Vibrating MEMS Resonator With Figure of Merit of 1560,” J. Microelectromech. Syst., vol. 27, no. 4, pp. 602-604, 2018.
[70] M. Kadota, and S. Tanaka, “Solidly mounted resonator using shear horizontal mode plate wave in LiNbO3 plate,” in Proc., IEEE Int. Freq. Contr. Symp. (IFCS’16), pp. 1-4, 2016.
[71] T. Kimura et al., “Comparative study of acoustic wave devices using thin piezoelectric plates in the 3–5-GHz range,” IEEE Trans. Microwave Theory Tech., vol. 67, no. 3, pp. 915-921, 2019.
[72] T. Kimura et al., “3.5 GHz longitudinal leaky surface acoustic wave resonator using a multilayered waveguide structure for high acoustic energy confinement,” Jpn. J. Appl. Phys., vol. 57, no. 7S1, pp. 07LD15, 2018.
[73] K. J. Tseng, and M. H. Li, “Frequency and Coupling Factor Scaling of Shear Horizontal SAW Resonators in LNOI Platform,” in Proc., IEEE Int. Freq. Contr. Symp. and Int. Symp. Appl. Ferro. (IFCS-ISAF’20), pp. 1-3, 2020.
[74] K. J. Tseng, and M. H. Li, “Low Loss Acoustic Delay Lines Based on Solidly Mounted Lithium Niobate Thin Film,” J. Microelectromech. Syst., vol. 29, no. 4, pp. 449-451, 2020.
[75] T. H. Hsu et al., “Low Loss and Wideband Surface Acoustic Wave Devices in Thin Film Lithium Niobate on Insulator (LNOI) Platform,” in Proc., 34th IEEE Micro Electro Mechanical Systems (MEMS’21), 2021, pp. 474-477.
[76] R. Nakagawa et al., “Low velocity I.H.P. SAW using Al/Pt electrodes for miniaturization,” in Proc., IEEE Int. Ultrason. Symp. (IUS’19), pp. 2083-2086, 2019.
[77] M. Kadota et al., “Suprious-Free, Near-Zero-TCF Hetero Acoustic Layer (HAL)SAW Resonators Using LiTaO3 Thin Plate on Quartz,” in Proc., IEEE Int. Ultrason. Symp. (IUS’18), pp. 1-9, 2018.
[78] S. Zhang et al., “Surface acoustic wave devices using lithium niobate on silicon carbide,” IEEE Trans. Microwave Theory Tech., vol. 68, no. 9, pp. 3653-3666, 2020.
[79] S. S. Hong et al., “P1L-3 Characteristics of LLSAW in Periodical Systems of Layered Electrodes,” in Proc., IEEE Int. Ultrason. Symp. (IUS’06), pp. 1513-1516, 2006.
[80] J. F. Rosenbaum, Bulk Acoustic Wave Theory and Devices: Artech House, 1988.
[81] R. Lu et al., “GHz Broadband SH0 Mode Lithium Niobate Acoustic Delay Lines,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 67, no. 2, pp. 402-412, 2020.
[82] I. E. Kuznetsova et al., “Investigation of acoustic waves in thin plates of lithium niobate and lithium tantalate,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 48, no. 1, pp. 322-328, 2001.
[83] J. Zou et al., “Transducer design for AlN Lamb wave resonators,” J. Appl. Phys., vol. 121, no. 15, 2017.
[84] J. Zou et al., “Ultra-Large-Coupling and Spurious-Free SH0 Plate Acoustic Wave Resonators Based on Thin LiNbO3,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 67, no. 2, pp. 374-386, 2020.
[85] S. H. Chang et al., “Analysis of methods for determining electromechanical coupling coefficients of piezoelectric elements,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 42, no. 4, pp. 630-640, 1995.
[86] M. Kadota, and S. Tanaka, “LT/Quartz HAL SAW Resonator with Large LT Thickness over Severalfold Wavelength,” in Proc., IEEE Int. Ultrason. Symp. (IUS’19), pp. 1223-1226, 2019.
[87] M. Kadota et al., “Surface Acoustic Wave Resonators With Hetero Acoustic Layer (HAL) Structure Using Lithium Tantalate and Quartz,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 68, no. 5, pp. 1955-1964, 2021.
[88] D. A. Feld et al., “After 60 years: A new formula for computing quality factor is warranted,” in Proc., IEEE Int. Ultrason. Symp. (IUS’08), pp. 431-436, 2008.
[89] R. Ruby et al., “Method of extracting unloaded Q applied across different resonator technologies,” in Proc., IEEE Int. Ultrason. Symp. (IUS’08), pp. 1815-1818, 2008.
[90] R. Jin et al., “An improved formula for estimating stored energy in a BAW resonator by its measured S11 parameters,” in Proc., IEEE Int. Ultrason. Symp. (IUS’21), pp. 1-5, 2021.
[91] R. Lu et al., “Accurate extraction of large electromechanical coupling in piezoelectric MEMS resonators,” J. Microelectromech. Syst., vol. 28, no. 2, pp. 209-218, 2019.
[92] N. Assila et al., “High-Frequency Resonator Using A1 Lamb Wave Mode in LiTaO3 Plate,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 66, no. 9, pp. 1529-1535, 2019.
[93] M. Kadota et al., “Resonator filters using shear horizontal-type leaky surface acoustic wave consisting of heavy-metal electrode and quartz substrate,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 51, no. 2, pp. 202-210, 2004.
[94] M. Kadota, and S. Tanaka, “Improved quality factor of hetero acoustic layer (HAL) SAW resonator combining LiTaO3 thin plate and quartz substrate,” in Proc., IEEE Int. Ultrason. Symp. (IUS’17), pp. 1-4, 2017.
[95] C. C. Yeh et al., “Sub-3 DB Insertion Loss Broadband Acoustic Delay Lines and High Fom Resonators in LiNbO3/SiO2/Si Functional Substrate,” in Proc., 36th IEEE Micro Electro Mechanical Systems (MEMS’23), 2023, pp. 1194-1197.
[96] G.-L. Wu, “Wideband surface acoustic wave filters in thin-film Lithium Niobate on insulator,” Master's thesis, Dept. of Power Mech. Eng., Nat. Tsing Hua Univ, Hsinchu, Taiwan, 2021.
[97] C. M. Lin et al., “Temperature-compensated aluminum nitride lamb wave resonators,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 57, no. 3, pp. 524-532, 2010.
[98] A. Ansari, and M. Rais-Zadeh, “A Temperature-Compensated Gallium Nitride Micromechanical Resonator,” IEEE Electron Device Lett., vol. 35, no. 11, pp. 1127-1129, 2014.
[99] M. A. Hopcroft et al., “What is the Young's Modulus of Silicon?,” J. Microelectromech. Syst., vol. 19, no. 2, pp. 229-238, 2010.
[100] Qorvo, “Redefining filter performance,” 2018; (Avalible at: https://www.qorvo.com/resources/d/qorvo-advanced-filtering-solutions-brochure.)
[101] R. Wang et al., “Design and Fabrication of S0 Lamb-Wave Thin-Film Lithium Niobate Micromechanical Resonators,” J. Microelectromech. Syst., vol. 24, no. 2, pp. 300-308, 2015.
[102] A. Kochhar et al., “X-Cut lithium niobate-based shear horizontal resonators for radio frequency applications,” J. Microelectromech. Syst., vol. 29, no. 6, pp. 1464-1472, 2020.
[103] Coilcraft, “Square air core inductors,” 0908SQ-8N1 datasheet, 2015.
[104] M. Kadota, and S. Tanaka, “Solidly mounted ladder filter using shear horizontal wave in LiNbO3,” in Proc., IEEE Int. Ultrason. Symp. (IUS’16), pp. 1-4, 2016.
[105] T. Nakao et al., “Smaller Surface Acoustic Wave Duplexer for US Personal Communication Service Having Good Temperature Characteristics,” Jpn. J. Appl. Phys., vol. 46, no. 7S, pp. 4760, 2007.
[106] T. Pastureaud et al., “High-frequency surface acoustic waves excited on thin-oriented LiNbO/sub 3/ single-crystal layers transferred onto silicon,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 54, no. 4, pp. 870-876, 2007.
[107] R. Wang et al., “Multi-frequency LiNbo3 Lamb wave resonators with < 3Ω impedance,” in Proc., 29th IEEE Micro Electro Mechanical Systems (MEMS’16), pp. 679-682, 2016.
[108] R. Lu et al., “Exploiting parallelism in resonators for large voltage gain in low power wake up radio front ends,” in Proc., 31th IEEE Micro Electro Mechanical Systems (MEMS’18), 2018, pp. 747-750.
[109] R. Su et al., “Wideband and Low-Loss Surface Acoustic Wave Filter Based on 15° YX-LiNbO₃/SiO₂/Si Structure,” IEEE Electron Device Lett., vol. 42, no. 3, pp. 438-441, 2021.
[110] Y. M. Huang et al., “S-band High Passive Gain Resonant Transformers Based on Aluminum Nitride FBAR Resonators,” in Proc., IEEE MTT-S Int. Microw. Symp. (IMS’22), pp. 891-894, 2022.
[111] U. Wolff et al., “SAW sensors for harsh environments,” IEEE Sens. J., vol. 1, no. 1, pp. 4-13, 2001.
[112] S. R. Eisner et al., “A laterally vibrating lithium niobate MEMS resonator array operating at 500 °C in air,” Sensors, vol. 21, no. 1, 2021.
[113] Y. Guo et al., “Hetero acoustic layer surface acoustic wave resonator composed of LiNbO3 and Quartz,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 71, no. 1, pp. 182-190, 2024.
[114] T. H. Hsu et al., “Miniature LiNbO3/SiO2/Si SH-SAW resonators with near-spurious-free response,” IEEE Electron Device Lett., vol. 44, no. 7, pp. 1200-1203, 2023.
[115] T. H. Hsu et al., “A dispersion-engineered YX-LN/SIO2/sapphire SH-SAW resonator for enhanced electromechanical coupling and rayleigh mode suppression,” in Proc., 37th IEEE Micro Electro Mechanical Systems (MEMS’24), pp. 27-30, 2024.
[116] T. H. Hsu et al., “Harnessing acoustic dispersions in YX-LN/SiO2/Si SH-SAW resonators for electromechanical coupling optimization and rayleigh mode suppression,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 70, no. 12, pp. 1786-1793, 2023.
[117] Y. A. Chang, and L. Himmel, “Temperature dependence of the elastic constants of Cu, Ag, and Au above room temperature,” J. Appl. Phys., vol. 37, no. 9, pp. 3567-3572, 1966.
[118] K. Yamanouchi et al., “Theoretical and experimental results of ultrawide-band zero-TCF ladder-type SAW filters and arbitrary bandwidth filters using high-coupling SiO2/Y-X LiNbO3,” Jpn. J. Appl. Phys., vol. 44, no. 6S, pp. 4520, 2005.
[119] M. Goto et al., “Optimization of gold film thickness for SH-SAW biosensor on quartz,” in Proc., IEEE Int. Ultrason. Symp. (IUS’13), pp. 2151-2154, 2013.
[120] D. Lu et al., “Humidity sensors based on photolithographically patterned PVA films deposited on SAW resonators,” IEEE Sens. J., vol. 16, no. 1, pp. 13-14, 2016.
[121] V. Yantchev et al., “A Spurious Free SH-SAW Resonator Employing a Novel Multilayer Stack,” in Proc., IEEE Int. Ultrason. Symp. (IUS’22), pp. 1-4, 2022.
[122] P. Liu et al., “A near spurious-free 6 GHz LLSAW resonator with large electromechanical coupling on X-cut LiNbO3/SiC bilayer substrate,” Appl. Phys. Lett., vol. 122, no. 10, 2023.
[123] J. Shen et al., “High-performance surface acoustic wave devices using LiNbO3/SiO2/SiC multilayered substrates,” IEEE Trans. Microwave Theory Tech., vol. 69, no. 8, pp. 3693-3705, 2021.
[124] F. Qian et al., “Twist Piezoelectric Coupling Properties to Suppress Spurious Modes for Lithium Niobate Thin-film Acoustic Devices,” in Proc., IEEE MTT-S Int. Microw. Symp. (IMS’23), pp. 907-910, 2023.
[125] W. Tsung-Tsong, and C. Yung-Yu, “Exact analysis of dispersive SAW devices on ZnO/diamond/Si-layered structures,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 49, no. 1, pp. 142-149, 2002.
[126] J. Zou et al., “Spectrum-clean S1 AlN Lamb wave resonator with damped edge reflectors,” Appl. Phys. Lett., vol. 116, no. 2, 2020.
[127] Y. H. Song, and S. Gong, “Spurious mode suppression in SH0 Lithium Niobate laterally vibrating MEMS resonators,” in Proc., IEEE Int. Electron Devices Mtg. (IEDM’15), pp. 18.5.1-18.5.4, 2015.
[128] Y. H. Song, and S. Gong, “Arraying SH0 Lithium Niobate laterally vibrating resonators for mitigation of higher order spurious modes,” in Proc., 29th IEEE Micro Electro Mechanical Systems (MEMS’16), pp. 111-114, 2016.
[129] Y. Liu et al., “A Novel Structure to Suppress Transverse Modes in Radio Frequency TC-SAW Resonators and Filters,” IEEE Microwave Wireless Compon. Lett., vol. 29, no. 4, pp. 249-251, 2019.
[130] J. Zou et al., “Transverse mode suppression in the AlN lamb wave resonators by “piston mode”,” in Proc., IEEE Int. Ultrason. Symp. (IUS’17), pp. 1-4, 2017.
[131] S. Inoue, and M. Solal, “LT/Quartz Layered SAW Substrate with Suppressed Transverse Mode Generation,” in Proc., IEEE Int. Ultrason. Symp. (IUS’20), pp. 1-4, 2020.
[132] S. S. Tung et al., “Suppression of Spurious Modes in Aluminum Nitride S1 Lamb Wave Resonators Using A Mechanical Soft-Contact Scheme,” in Proc., 36th IEEE Micro Electro Mechanical Systems (MEMS’23), pp. 1198-1201, 2023.
[133] T. H. Hsu et al., “Near-spurious-free lithium niobate-on-insulator SAW resonators for miniaturized GHz impedance transformers,” in Proc., IEEE Int. Ultrason. Symp. (IUS’23), pp. 1-4, 2023.
[134] M. Kadota et al., “Ultra-wideband and high frequency resonators using shear horizontal type plate wave in LiNbO3 thin plate,” Jpn. J. Appl. Phys., vol. 53, no. 7S, pp. 07KD03, 2014.
[135] H. Shimizu et al., “Love-type-SAW resonator of small size with very low capacitance ratio and its application to VCO,” in Proc., IEEE Int. Ultrason. Symp. (IUS’90), pp. 103-108 vol.1, 1990.
[136] T. Omori et al., “Suppression of transverse mode responses in ultra-wideband SAW resonators fabricated on a Cu-grating/15°YX-LiNbO3 structure,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 54, no. 10, pp. 1943-1948, 2007.
[137] S. Wu et al., “Tilted IDT designs for spurious modes suppression in LiNbO3/SiO2/Si SAW resonators,” IEEE Trans. Electron Devices, vol. 70, no. 11, pp. 5831-5838, 2023.
[138] Y. M. Huang et al., “S-band micromechanical resonant impedance transformers based on aluminum nitride FBARs,” IEEE Trans. Microwave Theory Tech., vol. 71, no. 10, pp. 4193-4205, 2023.
[139] T. L. Naing et al., “Low-Power MEMS-Based Pierce Oscillator Using a 61-MHz Capacitive-Gap Disk Resonator,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 67, no. 7, pp. 1377-1391, 2020.
[140] P. Bassirian et al., “Nanowatt-Level Wakeup Receiver Front Ends Using MEMS Resonators for Impedance Transformation,” IEEE Trans. Microwave Theory Tech., vol. 67, no. 4, pp. 1615-1627, 2019.
[141] J. Moody et al., “Interference Robust Detector-First Near-Zero Power Wake-Up Receiver,” IEEE J. Solid-State Circuits, vol. 54, no. 8, pp. 2149-2162, 2019.
[142] V. Mangal, and P. R. Kinget, “28.1 A 0.42nW 434MHz -79.1dBm Wake-Up Receiver with a Time-Domain Integrator,” in Proc., IEEE Int. Solid-State Circuits Conf. (ISSCC’19), pp. 438-440, 2019.
[143] M. E. G. Klemash et al., “1-Port Piezoelectric Resonators With > 100 V/V Gain,” J. Microelectromech. Syst., vol. 29, no. 5, pp. 874-880, 2020.
[144] L. Colombo et al., “High-Figure-of-Merit X-Cut Lithium Niobate MEMS Resonators Operating Around 50 MHz for Large Passive Voltage Amplification in Radio Frequency Applications,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 67, no. 7, pp. 1392-1402, 2020.
[145] L. Colombo et al., “VHF and UHF Lithium Niobate MEMS Resonators Exceeding 30 dB of Passive Gain,” IEEE Electron Device Lett., vol. 42, no. 12, pp. 1853-1856, 2021.
[146] A. Lozzi et al., “Al0.83Sc0.17N Contour-Mode Resonators With Electromechanical Coupling in Excess of 4.5%,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 66, no. 1, pp. 146-153, 2019.
[147] Y. Takamine et al., “A Novel 3.5 GHz Low-Loss Bandpass Filter Using I.H.P. SAW Resonators,” in Proc., Asia-Pacific Microw. Conf. (APMC’18), pp. 1342-1344, 2018.
[148] T. Komatsu et al., Acoustic wave resonator with transverse spurious mode for filter steepness, United States Patent 11451212,to Skyworks Solutions, Inc., USPTO, 2022.
[149] J. Zou et al., “Transverse Spurious Mode Compensation for AlN Lamb Wave Resonators,” IEEE Access, vol. 7, pp. 67059-67067, 2019.
[150] P. Zheng et al., “Gigahertz Acoustic Delay Lines in Lithium Niobate on Silicon Carbide With Propagation-Q of 11174,” IEEE Electron Device Lett., vol. 44, no. 2, pp. 309-312, 2023.
[151] V. Mangal, and P. R. Kinget, “Sub-nW Wake-Up Receivers With Gate-Biased Self-Mixers and Time-Encoded Signal Processing,” IEEE J. Solid-State Circuits, vol. 54, no. 12, pp. 3513-3524, 2019.
[152] T.-H. Hsu et al., “C-Band Lithium Niobate on Silicon Carbide Surface Acoustic Wave Resonator with Figure-of-Merit of 124 at 6.5 GHz,” arXiv preprint arXiv:2402.16732, 2024.
[153] T. H. Hsu et al., “Thin-Film Lithium Niobate on Insulator Surface Acoustic Wave Devices for 6G Centimeter Bands,” in Proc., IEEE MTT-S Int. Conf. on Microw. Acoustics & Mechanics (IC-MAM’24), pp. 117-120, 2024.
[154] M. Bousquet et al., “Lithium niobate film bulk acoustic wave resonator for sub-6 GHz filters,” in Proc., IEEE Int. Ultrason. Symp. (IUS’20), pp. 1-4, 2020.
[155] A. Hagelauer et al., “From Microwave Acoustic Filters to Millimeter-Wave Operation and New Applications,” IEEE J. Microwaves, vol. 3, no. 1, pp. 484-508, 2023.
[156] H. Holma et al., “Extreme massive MIMO for macro cell capacity boost in 5G-Advanced and 6G,” NOKIA BELL LABS, Finland, 2023; (Avalible at: https://onestore.nokia.com/asset/210786.)
[157] R. Vetury et al., “High Power, Wideband Single Crystal XBAW Technology for sub-6 GHz Micro RF Filter Applications,” in Proc., IEEE Int. Ultrason. Symp. (IUS’18), pp. 206-212, 2018.
[158] D. Kim et al., “Wideband 6 GHz RF Filters for Wi-Fi 6E Using a Unique BAW Process and Highly Sc-doped AlN Thin Film,” in Proc., IEEE MTT-S Int. Microw. Symp. (IMS’21), pp. 207-209, 2021.
[159] Y. Yang et al., “4.5 GHz Lithium Niobate MEMS Filters With 10% Fractional Bandwidth for 5G Front-Ends,” J. Microelectromech. Syst., vol. 28, no. 4, pp. 575-577, 2019.
[160] O. Barrera et al., “Thin-Film Lithium Niobate Acoustic Filter at 23.5 GHz With 2.38 dB IL and 18.2% FBW,” J. Microelectromech. Syst., vol. 32, no. 6, pp. 622-625, 2023.
[161] S. Cho et al., “23.8-GHz Acoustic Filter in Periodically Poled Piezoelectric Film Lithium Niobate With 1.52-dB IL and 19.4% FBW,” IEEE Microwave and Wireless Technology Lett., vol. 34, no. 4, pp. 391-394, 2024.
[162] R. Truell et al., Ultrasonic Methods in Solid State Physics: Academic Press, 1969.
[163] G. Giribaldi et al., “Compact and wideband nanoacoustic pass-band filters for future 5G and 6G cellular radios,” Nat. Commun., vol. 15, no. 1, pp. 304, 2024.
[164] P. Jacot et al., Surface acoustic wave device having improved performance and method of making the device, United States Patent 7148610, USPTO, 2006.
[165] R. Lu, and S. Gong, “A 15.8 GHz A6 Mode Resonator with Q of 720 in Complementarily Oriented Piezoelectric Lithium Niobate Thin Films,” in Proc., 2021 Joint Conf. of Eur. Freq. Time Forum - IEEE Int. Freq. Contr. Symp. (EFTF-IFCS’21), pp. 1-4, 2021.
[166] M. Kadota et al., “High-frequency lamb wave device composed of MEMS structure using LiNbO3 thin film and air gap,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 57, no. 11, pp. 2564-2571, 2010.
[167] V. Plessky et al., “Laterally excited bulk wave resonators (XBARs) based on thin Lithium Niobate platelet for 5GHz and 13 GHz filters,” in Proc., IEEE MTT-S Int. Microw. Symp. (IMS’19), pp. 512-515, 2019.
[168] R. Vetury et al., “A Manufacturable AlScN Periodically Polarized Piezoelectric Film Bulk Acoustic Wave Resonator (AlScN P3F BAW) Operating in Overtone Mode at X and Ku Band,” in Proc., IEEE MTT-S Int. Microw. Symp. (IMS’23), 2023, pp. 891-894.
[169] D. Mo et al., “Complementary-Switchable Dual-Mode SHF Scandium Aluminum Nitride BAW Resonator,” IEEE Trans. Electron Devices, vol. 69, no. 8, pp. 4624-4631, 2022.
[170] Y. Shen et al., “452 MHz Bandwidth, High Rejection 5.6 GHz UNII XBAW Coexistence Filters Using Doped AlN-on-Silicon,” in Proc., IEEE Int. Electron Devices Mtg. (IEDM’19), pp. 17.6.1-17.6.4, 2019.
[171] R. Kubo et al., “Fabrication of 5GHz band film bulk acoustic wave resonators using ZnO thin film,” in Proc., IEEE Int. Ultrason. Symp. (IUS’03), pp. 166-169, 2003.
[172] L. Zhang et al., “High-Performance Acoustic Wave Devices on LiTaO3/SiC Hetero-Substrates,” IEEE Trans. Microwave Theory Tech., vol. 71, no. 10, pp. 4182-4192, 2023.
[173] R. Su et al., “5.9 GHz Longitudinal Leaky SAW Filter With FBW of 9.2% and IL of 1.8 dB Using LN/Quartz Structure,” IEEE Microwave and Wireless Technology Lett., vol. 33, no. 10, pp. 1434-1437, 2023.
[174] Z. Dai et al., “Coupled Shear SAW Resonator With High Electromechanical Coupling Coefficient of 34% Using X-Cut LiNbO₃-on-SiC Substrate,” IEEE Electron Device Lett., vol. 45, no. 4, pp. 720-723, 2024.
[175] L. Zhang et al., “Spurious-Free and Low-Loss Surface Acoustic Wave Filter Beyond 5 GHz,” in Proc., IEEE Int. Ultrason. Symp. (IUS’23), pp. 1-4, 2023.
[176] R. Lu et al., “Enabling Higher Order Lamb Wave Acoustic Devices With Complementarily Oriented Piezoelectric Thin Films,” J. Microelectromech. Syst., vol. 29, no. 5, pp. 1332-1346, 2020.
[177] J. Zhang et al., “Surface acoustic wave bound state in the continuum for 1200 °C high temperature sensing,” J. Micromech. Microeng., vol. 34, no. 7, pp. 075003, 2024.
[178] Y. Yang et al., “10–60-GHz Electromechanical Resonators Using Thin-Film Lithium Niobate,” IEEE Trans. Microwave Theory Tech., vol. 68, no. 12, pp. 5211-5220, 2020.
[179] Izhar et al., “A K-Band Bulk Acoustic Wave Resonator Using Periodically Poled Al0.72Sc0.28N,” IEEE Electron Device Lett., vol. 44, no. 7, pp. 1196-1199, 2023.
[180] S. Cho et al., “Millimeter Wave Thin-Film Bulk Acoustic Resonator in Sputtered Scandium Aluminum Nitride,” J. Microelectromech. Syst., vol. 32, no. 6, pp. 529-532, 2023.
[181] J. Zhou et al., “Record-Breaking Frequency of 44 GHz Based on the Higher Order Mode of Surface Acoustic Waves with LiNbO3/SiO2/SiC Heterostructures,” Engineering, vol. 20, pp. 112-119, 2023.