Broadcast systems: new requirements for antenna designs and propagation knowledge

摘要

Broadcasting of one sort or another has comfortably existed in the frequency range from 150 kHz to approaching 1 GHz for some considerable time, during which an accumulated wealth of knowledge of radiowave propagation of relevance to the broadcasting environment has emerged. That is not to say, however, that ones knowledge is in any way complete. The phenomenal growth in computing power during the 1980s enables the application of rigorous mathematical models to be used for service coverage and interference calculations, as compared with reliance on empirically based methods as in the past. The two can however be used in a complementary way. As far as antenna design is concerned there has been a continual development of more complex, sophisticated and efficient transmit antenna systems. The author considers some of the imminent or probable broadcast systems (terrestrial and satellite) in the light of requirements for propagation knowledge and implications on antenna design.