The piezoelectric energy harvesting characteristics of a trapezoidal cantilever generator with lead zirconate titanate (PZT) laminate were investigated with various Ag inner electrodes. The piezoelectric mode of operation was a transverse mode by using a planar electrode pattern. The piezoelectric cantilever generator was fabricated using trapezoidal cofired-PZT/Ag laminates by five specimens of 2, 3, 4, 7, and 13 layers of Ag. As the number of Ag electrodes increased, impedance and output voltage at resonant frequency significantly decreased, and capacitance and output current showed an increasing tendency. A maximum output power density of 7.60 mW/cm³ was realized for the specimen with seven Ag layers in the optimal condition of acceleration (1.2 g) and resistive load (600 Ω), which corresponds to a normalized power factor of 5.28 mW/g²·cm³.

Energy harvesting characteristics of trapezoidal piezoelectric cantilever generator, which has a lead zirconate titanate (PZT) laminate film, were compared by longitudinal (3-3) and transverse (3-1) modes. The PZT laminate film, fabricated by a conventional tape casting process, was cofired with Ag electrode at 850℃ for 2 h. A multi-layered Ag electrode by a planar pattern and an interdigitated pattern was applied to the PZT laminate to implement the 3-3 and 3-1 modes, respectively. The energy harvesting performance of the 3-3 mode trapezoidal piezoelectric cantilever generator was better than that of the 3-1 mode. An extremely high output power density of 26.7 mW/cm³ for the 3-3 mode was obtained at a resonant frequency of 145 Hz under a load resistance of 50 ㏀ and acceleration of 1.3 G, which is ~3-times higher than that for the 3-1 mode. Therefore, the 3-3 mode is considered significantly efficient for application to high-performance piezoelectric cantilever generator.

In this paper, we designed and fabricated low cost imprinting process for micro patterning on FCCL (flexible copper clad laminate). Compared to conventional imprinting process, developed fabrication method processing imprint and UV photolithography step simultaneously and it does not require resin etch process and it can also reduce the fabrication cost and processing time. Based on proposed method, patterns with 10 ㎛ linewidth are fabricated on 180 ㎜ × 180 ㎜ FCCL. Compared to conventional methods using LDI (laser direct imaging) equipment that showed minimum line with 10 ∼ 20 ㎛, proposed method shows comparable pattern resolution with very competitive price and shorter processing time. In terms of mass production, it can be applied to fabrication of large-area low cost applications including FPCB.

The magnetoelectric characteristics on layered Ni-PZT-Ni, Co, Fe composites by epoxy bonding for magnetic field sensor were investigated in the low-frequency range. The ME coefficient of Ni-PZT-Ni, Ni-PZT-Co and Ni-PZT-Fe composites reaches a maximum of 200 mV/cm·Oe at Hdc=110 Oe, 106 mV/cm·Oe at Hdc=90 Oe and 87 mV/cm·Oe at Hdc=160 Oe, respectively. A trend of ME charateristics on Ni-PZT-Co, Ni-PZT-Fe composites was similar to that of Ni-PZT-Ni composites. The ME output voltage shows linearly proportional to ac field Hac and is about 0∼150 mV at Hac=0∼7 Oe and f=110 Hz in the typical Ni-PZT-Ni sample. The frequency shift effect due to the load resistance RL shows that the frequency range for magnetic field sensor application can be modulated with appropriate load resistance RL. This sample will allow for a low-magnetic ac field sensor in the low-frequency (near f=110 Hz).