Balanced front-end hybrid SAW modules with impedance conversion

This paper presents the new balanced front-end hybrid SAW modules with impedance conversion in a fractional bandwidth of 1.5-7% for 146-174 MHz handheld transceivers. The modules are connected between a low impedance antenna and high impedance double balanced mixer (DBM). 2 balanced SAW filters connected across a low noise amplifier are used in these modules. The balanced low-loss ring SAW filters on 128 /spl deg/YX LiNbO/sub 3/ and three-transducer SAW filters with unidirectional IDTs having U-shaped MSCs on 128/spl deg/YX, 64/spl deg/YX, 41/spl deg/YX LiNbO/sub 3/ are used. An optimization of a SAW filter-amplifier-SAW filter system was provided with a computer simulation using the equivalent circuit model. The 155-169 MHz balanced front-end SAW modules have shown a 3-dB bandwidth of 2.3-11 MHz, 12 dB gain, suppression above 80 dB. The modules are housed in the 16/spl times/7.3/spl times/2.6 mm SMD packages.