Hybrid SAW integrated modules with RFA and VCO for mobile transceivers

This paper presents hybrid SAW modules with RF amplifier (RFA) and voltage controlled oscillator (VCO) for 146-174, 440-470 MHz mobile communication receivers. The module with RFA consisted of two SAW filters connected across the amplifier. 148.5, 460 MHz hybrid SAW modules with RFA and low-loss ring filters on 128°YX LiNbO₃ have shown very low amplitude ripple of 0.1 dB within the 2 dB bandwidth about 1.5%, gain from 15 to 28 dB at 50 Ohm, local oscillator frequency and image frequency suppression over 90 dB at ±20.5 and ±41 MHz offsets respectively from the center frequency. We used VCO with SAW delay line and external phase shifter in the amplifier feedback loop. For the delay lines we used previously developed low-loss SAW ring filters on 128°YX, 64°YX, 49°YX. 169, 480 MHz VCOs with SAW filters on 64°YX were developed and 148.5, 460 MHz modules with RFA having SAW filters on 128°YX are optimally combined. In this case for the variable frequency range about 2% and C/N of 85 dB control voltage from 0.5 to 5 volts is required. Hybrid SAW modules with RFA and VCO had small size and were mounted in 14.5×19.5×5 mm and 22×19.5×5 mm glass-and-metal packages