In this paper; we present three monolithical microwave integrated circuits (MMICâ€™s) that potentially may be used in the receiver front-ends of future wide-band multi-purpose array antennas; for example. Two low-noise amplifiers (LNAâ€™s) and one tunable filter have been designed in a 0.35Âµm bipolar complementary metal oxide semiconductor (BiCMOS) technology containing high frequency silicongermanium SiGe) hetero-junction bipolar transistors (HBTâ€™s). The use of BiCMOS technologies based on SiGe HBTâ€™s to enhance RF performance could enable RF functions to be integrated on the same chip as complex digital functions. Firstly; a single-stage LNA is presented together with a twostage wide-band LNA. Simulated RF performance of these circuits seems promising in terms of values of gain and noise figure achieved; respectively; over large bandwidths. Relatively wide-band input and output impedance matching together with reasonably low values of power consumption are achieved for these LNAâ€™s. Finally; a 7.3-8.1GHz tunable active filter is also described.