A new balanced-unbalanced type RF-band SAW filter

A new balanced-unbalanced type RF-band (950 MHz) surface acoustic wave (SAW) filter for use in portable telephones is presented. This SAW filter has unbalanced input and balanced output terminals. Balanced-unbalanced type SAW filters having a pass-band at 950 MHz were fabricated. The obtained results showed excellent characteristics such as low insertion loss, wide bandwidth, and small VSWR. Using the SAW filter, one can realize balanced-type RF circuits in portable telephones.