We have obtained an excitation of longitudinal bulk acoustic waves in a diamond-based High overtone Bulk Acoustic Resonator (HBAR) at microwave and enhanced frequency bands as EHF up to 40 GHz. As an effective piezoelectric transducer, an aluminum-scandium nitride film is employed. The frequency response of acoustic overtones excited in the HBARs with a different aperture in the 1.0 up to 40 GHz range is measured. Some peculiarities of HBAR's frequency response concerned with the thin film piezoelectric transducer are studied. It is established that the maximal magnitude of the quality factor varies near the value of about 10 000 within all the frequency bands investigated. The approximately frequency-independent Q-factor behavior can explain in terms the Landau–Rumer approximation describing the acoustic attenuation in a diamond. An estimation of the HBAR's quality parameter as Q × f ≈ 4 × 10¹⁴ Hz at 40 GHz is obtained. In our opinion, that value exceeds all known data among the given devices. The results obtained will be helpful in the development of microwave and EHF acoustic resonators as well as highly sensitive acoustic sensors. The development of the EHF band opens up the possibility of obtaining acoustic waves of submicrometer and nanometer scales (in various media) and implementing acoustic studies of micro- and nanoobjects.

中文翻译：

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钻石基HBAR的40 GHz激发

我们已经获得了基于金刚石的高泛音体声谐振器（HBAR）在微波中的纵向体声波的激发，并增强了高达40 GHz的EHF频段。作为有效的压电换能器，采用铝-氮化物膜。测量了在1.0到40 GHz范围内具有不同孔径的HBAR中激发的音频泛音的频率响应。研究了与薄膜压电换能器有关的HBAR频率响应的一些特点。可以确定，在所研究的所有频带内，品质因数的最大幅度都在大约10000的值附近变化。近似于频率的Q因子行为可以用Landau–Rumer近似来解释描述钻石中声衰减的术语。该HBAR的质量参数作为估计Q  ×  ˚F  ≈4×10 ¹⁴  ，获得在40 GHz的赫兹。我们认为，该值超过了给定设备中的所有已知数据。获得的结果将有助于微波和EHF声谐振器以及高灵敏声传感器的开发。EHF频段的发展开辟了获得亚微米和纳米级声波（在各种介质中）以及进行微米和纳米物体声学研究的可能性。