Low-cost flat-plate array with squinted beam for dbs reception

There is a great deal of interest in the replacement of reflector antennas by low-cost wall-mounted fiat-plate antennas for the reception of satellite signals. The paper describes the extent to which combline microstrip technology can be used to obtain a squinted, circularly polarised beam at very low cost. The antenna presented consists of a simple travelling wave printed structure comprising a foam/metal sandwich with metal strip polariser. Performance parameters such as bandwidth, dissipative loss and pattern quality are examined and the effect of manufacturing tolerances are discussed. Finally, comparisons are made with reflector antennas and other flat-plate designs, with particular reference to the DBS specification; the possibility of introducing beam control capabilities into the array is con-sidered. It is concluded that the development of suitable low-cost substrates is a key issue and electronic beam control raises problems of a more fundamental nature.