In ultrasound tissue harmonic imaging (THI), it is preferred that the bandwidth of the array transducer covers at least the fundamental frequency f₀ for transmission and the second harmonic frequency 2f₀ for reception. However, it is challenging to develop an array transducer with a broad bandwidth due to the single resonance characteristics of piezoelectric materials. In this study, we present an improved interleaved array transducer suitable for THI and a dedicated transducer fabrication scheme. The proposed array transducer has a novel structure in which conventional elements exhibiting f₀ resonant frequency and polarization-inverted elements exhibiting 2f₀ resonant frequency are alternately located, and the thicknesses of all piezoelectric elements are identical. The performance of the proposed method was demonstrated by finite element analysis (FEA) simulations and experiments using a fabricated prototype array transducer. Using the proposed technique, f₀ and 2f₀ frequency ultrasounds can be efficiently transmitted and received, respectively, resulting in a 90% broad bandwidth feature of the transducer. Thus, the proposed technique can be one of the potential ways to implement high resolution THI.

中文翻译：

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具有极化反转技术的交错阵列换能器，可实现超声组织谐波成像。

在超声组织谐波成像（THI）中，优选的是，阵列换能器的带宽至少覆盖用于发送的基本频率f ₀和用于接收的第二谐波频率2f ₀。然而，由于压电材料的单共振特性，开发具有宽带宽的阵列换能器是具有挑战性的。在这项研究中，我们提出了一种适用于THI的改进的交错阵列换能器和专用换能器制造方案。所提出的阵列换能器具有新颖的结构，其中常规元件表现出f ₀谐振频率，而偏振反转的元件表现出2f ₀谐振频率交替放置，所有压电元件的厚度相同。通过有限元分析（FEA）模拟和使用预制原型阵列换能器进行的实验证明了该方法的性能。使用提出的技术，可以分别有效地发送和接收f ₀和2f ₀频率的超声波，从而产生换能器90％的宽带宽特征。因此，提出的技术可能是实现高分辨率THI的潜在方法之一。