11 GHz FET Amplifier for Multi Carrier Reception in Digital Radio-Relay Applications

This paper presents the design and performance of a FET amplifier in the 10.7 to 11.7 GHz bandwith. This amplifier was designed for multicarrier reception (4 channels) of a 8PSK 140 Mbit digital radio link to be placed just behind the antenna, an arrangement which improves the performance of the repeater and allows for more sophisticated modulation or for the use of an all solid-state transmitter. However a delicate compromise between noise figure, gain and intermodulation products must be achieved: this is why a "working area" for the amplifier has been defined from experimental degradation (Multipath fading, constructive interferences, ...). Each stage of the amplifier has been optimized for this goal and 5 dB noise figure and 23 dBm intercept point have been obtained for a 17 dB gain amplifier.