TABLE OF CONTENTS Future electronic steerable array radars will offer multifunction operation capabilities. They will be achieved with active array antennas applying individual transmit/receive modules for each antenna element. The transmit power amplifiers will be made with solid-state devices. The future cost-effective solution is the application of monolithic microwave integrated circuits (MMIC). The advantages of distributed transmit power generation are:
highest efficiency for generation of RF power from DC
high radiated power by superposition of the wave field from all elemental contributions in space
extreme long systems' MTBF by very long individual MTBF for solid-state amplifiers combined with graceful degradation of the total array by high numbers of parallel channels
avoidance of high-voltage power supplies
variable pulse length for different radar tasks
The peak power of transistor amplifiers is at maximum twice the mean power. In the case of GaAs FET amplifiers the possible mean power can even equal the peak power. Therefore, to utilise the available mean power the transmit pulses have to be as long as possible, especially for long-range operations. Furthermore, a multiplicity of pulse waveforms are to be applied, dependent on the specific radar task, e.g. search for new targets and acquistion or tracking of already detected targets at various ranges [1]. With long pulses arises the problem of blind ranges which afford special waveform combinations. Despite long pulses the range resolution has to be achieved using suitable modulation of the pulses in combination with pulse compression on the receiving side.
For special radar concepts, e.g. omnidirectional...
