1.9 GHZ LOW-LOSS SURFACE-ACOUSTIC-WAVE FILTER - LIFT-OFF METHOD AND 3MM SQUARE SMALL-SIZE PACKAGE

A novel 1.9 GHz low-loss surface acoustic wave (SAW) filter for person al handy phone systems has been produced. The 0.5 mum line and space e lectrode of SAW filter on the LiTaO3 substrate was fabricated by the l ift-off process using negative photoresist. A deep UV light source was used in the photo exposure process. Electrodes with 0.2 mum gap could be easily formed by the lift-off process. This SAW filter chip was mo unted in the new small size (3.0 mm square) leadless ceramic package. Because the parasitic inductance and capacitance of this package are s maller than the usual 4.8 mm X 5.2 mm package, a 1.9 GHz filter with s mall insertion loss of 1.7 dB was obtained. The suppression level if t his filter at 4.5 GHz was greater than 30 dB.