A perspective on array antenna developments

Although the first array antennas were developed long ago, it took considerable time and effort before the electronically phased array antennas reached the marketplace. Their full potential could initially not be exploited without the availability of advanced integrated circuits and computer technology. The developments of electromagnetic analysis methods and simulation tools have of course also played a significant role. Still, a phased array antenna is costly, and it has to be proven that the improvements in system functionality and performance are worth the extra cost. The modern trend is towards digital processing of the received array element signals, i.e. using the spatial dimension in addition to the traditional time/frequency (range & doppler, coding...) dimensions. In this way the desired information can be extracted more efficiently and at the same time provide interference rejection, improved signal quality, higher resolution etc. A corresponding scheme is not possible on the transmit side, but the spatial dimension can also here be used advantageously. Thus, the modern antenna array is typically integrated with other subsystems, forming an antenna system where the critical parts are optimized together. The development of new system simulation tools and subsystem interface descriptions will be necessary to facilitate the interdisciplinary efforts needed.