WIDEBAND SURFACE MOUNT HYBRID SAW MODULES WITH RFA FOR 146-174 MHZ MOBILE TRANSCEIVERS

摘要

This paper presents wideband surface mount hybrid modules with SAW filters for 146-174 mobile transceivers: the receiver modules with RF amplifier (RFA) having a fractional bandwidth of 3-7 %. These modules were mounted in the 16x7.3x2.6 mm SMD packages. The low-loss wideband three-transducers SAW filters using unidirectional IDTs on U-shaped MSCs on 128°YX, 64°YX, 41°YX LiNbO_3 were used. The modules were connected between a low impedance antenna and high impedance mixer in the receiver section of the mobile transceivers and used for the local oscillator frequency and image frequency suppressions. The modules contained two weighted SAW filters: the first filter with low input/output impedances, the second filter with high input/output impedances, connected across a low noise RFA on the one bipolar transistor. The 155, 165, 169 MHz samples of the surface mount hybrid SAW modules with RFA have shown an amplitude ripple of 1 dB within a 3-dB bandwidth of 4.65-11 MHz, 16 dB gain, suppression about 80 dB at +- 12 - +- 25 MHz offsets from the center frequency. A low noise and high intermodulation selectivity were provided with low power consumption. The new hybrid SAW modules have a wide bandwidth, small size and are compatible with SMT.