A Wideband Transistor IF Amplifier for Space and Terrestrial Repeaters Using Grounded-Base Transformer-Coupled Stages

The general objectives of the work discussed in this paper are as follows: (i) To design a wideband IF amplifier suitable for use on heavy-route, long-haul microwave radio relay systems.1,2 (ii) To design a wideband IF amplifier with low power consumption and good temperature stability for use in microwave radio relay systems3,4 which may be battery powered and which must operate at outdoor ambient temperatures. In accordance with these objectives it was decided to design an amplifier to be substantially flat over a 40-mc band centered at 70 mc. Transistors were chosen as the active elements because of the low bias power required, and the common-base circuit configuration was selected because it appeared likely to result in a stable band shape with respect to temperature. A part of the initial philosophy was to start with a stable wideband amplifier. The desired frequency selective circuits could then be added as linear lumped circuits whose gain and phase properties are in good control. Such circuits could include any desired gain and phase equalization. This approach results in an IF amplifier with an excellent delay characteristic. 37