A simple DBS receiving antenna-a tripole antenna

Results of an investigation of a tripole antenna for DBS (direct broadcast satellite) systems are presented. A tripole of a=1.25 mm, h=50 mm, g=18.75 mm, and d=18.75 mm operating at 12 GHz is chosen as the representative antenna. The variation in the input admittances of the representative tripole with respect to the change in its driving point is plotted. The directivity of a tripole with a ground plane is approximately 3 dB better than that of a dipole. A tripole, with its relatively wide beamwidth, can be used as an inexpensive feed in a reflector antenna. It is noted that although a self-contained tripole may be good enough to pick up a telephone conversation in a satellite based mobile phone system, it is not adequate to receive a TV signal in a DBS system. To improve the overall gain of a tripole, parasitic elements must be added.<>