On Functional Modules Based on Integration of Acoustic Wave Devices and Semiconductor Circuitry

本项目旨在从不同角度探讨射频声波器件与半导体电路集成实现功能射频模块的可能性。首先，研究了射频声波器件对功率放大器性能的影响。结果表明，高频滤波器的阻抗Z对功率放大器的功率附加效率(PAE)有显著影响，指出要实现高的PAE，必须抑制Z的变化。还指出，由于在高功率运行时，非线性明显，因此谐波频率的Z对于实现高PAE也是重要的。作为一种对策，通过在两个射频滤波器上连接两个90°混合体，可以完全抑制Z变化，并通过实验验证了该方法的有效性。然后，我们讨论了利用铜电极/15°YX-LiNbO_3衬底结构实现新型功能表面波(SAW)器件。结果表明，只需增加铜层厚度，就可以抑制体波辐射的影响。这种技术对于降低滤光片插入损耗是有效的。在此基础上，提出了采用加权虚拟电极和表面涂覆粘性材料的方法来抑制滤波通道中出现的不必要的响应，并提出了将射频放大器和滤波器相结合的各种新型功能器件，并从不同方面详细讨论了适合于此目的的器件结构。

This project was aimed at discussing possibilities of functional RF modules realized by the integration of RF acoustic wave devices and semiconductor circuitry from various aspects.First, influence of RF acoustic wave devices to the power amplifier (PA) performances was investigated. It was shown that the impedance Z of RF filters significantly influences to the power added efficiency (PAE) of PAs at high power operation, and it was pointed out that Z variation must be suppressed to realize high PAE. It was also indicated that Z for harmonic frequencies is also important for the high PAE realization because non-linearity is obvious at high power operation. As a countermeasure, it was shown that Z variation can be fully suppressed by attaching two 90° hybrids to two RF filters, and effectiveness of this approach was demonstrated experimentally.Then we discussed realization of new functional surface acoustic wave (SAW) devices by the use of Cu-electrode/15°YX-LiNbO_3-substrate configuration. It was shown that the influence of the bulk wave radiation can be suppressed by simply increasing Cu thickness. This technique is effective for the reduction of the filter insertion loss. Then use of weighted dummy electrodes and over-coating viscous materials were proposed for the suppression of unnecessary responses appeared in the filter passband.Furthermore, we proposed new various functional devices such as various filters combining RF amplifiers and filters, and device configurations appropriate for the purposes were also discussed in detail from various aspects.