A Novel Design and Simulation of a Ku Broadband Double Ridged Guide Horn Antenna for Satellite Communications

This paper presents the design and the simulation of a modified Ku broadband double ridged guide horn antenna (DRGH) feed by a coaxial input. On board the satellites, the horn antennas play an important role in the wider bandwidth services. Telecommunication satellite horn antennas are need due to the additional necessary bandwidth. Advantages of using this type of antenna are: a wide bandwidth to operate over, adequate directivity, high power and its simple construction. Traditionally, the most desired electromagnetic characteristics of this antenna are achieved by empirically finding sizes for different parameters. The optimized shape and dimensions of the antenna are determined in order to meet the specifications of a satellite communications scenario. For this a suitable taper for the ridges in the horn was designed and its impedance variations along the horn were shown. A step by step method is presented for the design of the DRGH antenna. In order to have a clear view regarding the effects of different parameters, Ansoft HFSS was used for the simulations of the DRGH in the range of operating frequencies. The antenna performance is evaluated in terms of gain, directivity, polarization, radiation patterns, voltage standing wave ratio (VSWR) and field in plane E. The new design brings a higher gain and a good VSWR for the frequency range of Ku band. For a better matching of the feeder's characteristic impedance, the impedance bandwidth efficiency was broadened. The results show that the parameters near feeding point (the initial distance between ridges, the distance between the center of the probe and the cavity, the radius of inserted probe) play a significant role in controlling VSWR, gain, and in shaping the radiation pattern for high frequencies. By comparing it with the conventional version, the proposed antenna comes with a considerably better performance, smaller physical dimensions and less weight.