การออกแบบสายอากาศยากิ-อุดะสำหรับการควบคุมการจราจรทางอากาศ / ศิริชัย รักษาพล = A design of the Yagi-Uda antenna for air traffic control purposes / Sirichai Raksaphon
Air/ground communication antennas for air traffic control are an important element apart from the human element. The frequency band for aeronautical navigation are assigned in the frequency range 118-137 MHz. The frequency of operation and the coverage area dictate the choice of the antenna type to be the yagi-uda. The radiation pattern of the anatenna must suitably cover the control area. The simple desired coverage pattern of the antennas are defined from the geographical coverage and airway routes in the control area. The first step is to obtain, by approximate design, a set of parameters of the desired antenna, and then analyse with the moment method by using the entire-domain basis functin for current distribution on all elements and the dirac delta function as the weighting function. Results are compared with the desired pattern. If the obtain pattern is not satisfactory alteration of parameters such as the element length, element spacing and number of elements is effected until the best pattern is achieved. The objective of this research is to develop new antenna that can be used in air traffic control between the aircraft and the ground station, which reduce power loss in non-contol area and co-channel interference of radio air/ground station. The measured far field radiation patterns are compared with the designed radiation patterns. There are discrepancies in the mainbeam. The measured ones are smaller than the designed. When use the measured pattern are placed on the control area there are some discrepencies but acceptatle, because it can cover the airway route in the control area.
