Jun Koike

Quasi-microwave band longitudinally coupled surface acoustic wave resonator filters using ZnO/sapphire substrate

The 1.5 and 2.4 GHz range 5IDT-type longitudinally coupled surface acoustic wave (SAW) resonator filters have been developed using ZnO/sapphire substrate. The 1.5 GHz range SAW filter has the minimum insertion loss of 1.0 dB and the relative bandwidth of 2.4% at the insertion loss of 3 dB. The 2.4 GHz range SAW filter has the minimum insertion loss of 1.7 dB and the relative bandwidth of 1.7% at the insertion loss of 3 dB. These filters are suitable for use as RF-stage filters in a personal digital cellular (PDC) system terminal and a wireless local area network (LAN) adapter, respectively.

Microwave low insertion loss SAW filter by using ZnO/sapphire substrate with Ni dopant

Microwave low insertion loss SAW filters are realized by using ZnO epitaxial films on a sapphire substrate. The epitaxial growth conditions and dopant are carefully determined to realize low propagation loss and high stability. 1.5 to 2.5 GHz range SAW filters are fabricated with an insertion loss of only 1 to 2 dB and outline dimensions of 0.01 to 0.02 cc.

1.86 GHz SAW Filter

Using the third order harmonic wave of Sezawa-mode which propagates in ZnO films epitaxially deposited on R-plane sapphire, high performance filter which is a low insertion loss of 9 dB at 1.86 GHz has been realized.