Ken-ya Hashimoto

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This paper describes a circuit model for the analysis of nonlinearity in the filters based on radiofrequency (RF) bulk acoustic wave (BAW) resonators. The nonlinear output is expressed by a current source connected parallel to the linear resonator. Amplitude of the nonlinear current source is programmed proportional to the product of linear currents flowing(More)
The paper describes how the characteristics of leaky surface acoustic wave (LSAW) propagation depend on the thickness of Al grating electrodes on rotated Y-X LiTaO3. It is shown that the propagation loss arising from leaky nature changes parabolically with both the grating electrode thickness and rotation angle and becomes zero when electrode thickness and(More)
A SiO(2)/Al/LiNbO(3) structure has a large electromechanical coupling factor (K(2)) and good temperature coefficient of frequency (TCF) for applications as a SAW duplexer of the Universal Mobile Telecommunications System (UMTS) Band I. However, the SiO(2)/Al/LiNbO(3) structure also supports two unwanted spurious responses; one is caused by the Rayleigh mode(More)
In recent, orthogonal frequency division multiple access (OFDMA) has been used for a multiuser wireless communication. In a wireless network, the transmitted signal of each user has independent channel fluctuation characteristic. By using this characteristic, OFDMA can achieve the multiuser diversity (MUDiv). Until this time, to achieve a low complexity and(More)
Diamond has the highest known SAW phase velocity, sufficient for applications in the gigahertz range. However, although numerous studies have demonstrated SAW devices on polycrystalline diamond thin films, all have had much larger propagation loss than single-crystal materials such as LiNbO3. Hence, in this study, we fabricated and characterized one-port(More)
A direct-conversion receiver (DCR) reduces the power consumption and cost. However, DCR in Orthogonal frequency division multiplex (OFDM) systems suffer from IQ imbalance. Until this time, many algorithms are proposed to compensate IQ imbalance in OFDM. However, the complexity is still considerable work. On the other hand, time-frequency interferometry-OFDM(More)
This paper is aimed at demonstrating how the wavenumber domain analysis of two-dimensional (2-D) images captured by phase-sensitive laser probe systems is applied in the characterization of RF SAW devices. Effectiveness is demonstrated through the selective characterization of spurious resonance modes and scattered, nonguided modes appearing in SAW(More)
This paper describes full-wave analysis of piezoelectric boundary acoustic waves (PBAWs) propagating along a metallic grating sandwiched between 2 semi-infinite layers. In the analysis, the finite element method (FEM) is used for the grating region while the spectral domain analysis (SDA) is applied for an isotropic overlay region as well as a piezoelectric(More)
This paper describes an attempt to develop extremely wideband multi-mode surface acoustic wave (MMS) filters in the gigahertz range. The Cu-grating/15 degrees YX-LiNbO3 (15-LN)-substrate structure is employed. First, a design tool developed for the present purpose is detailed. Precise simulation is performed using a modified coupling-of-modes model, in(More)