Analysis Of Millimeter Wave Radial Line Slot Antenna

In recent years, millimeter wave systems have many wide applications because of their small, light and wideband properties. With characteristics of high efficiency, low side lobe suppression, the slot antennas based on rectangular waveguide have been widely used in ground, naval vessel, airplane, navigation, harbor administration, beaconing, radar, etc. after the Second World War. With the increase of frequency, the machining of this kind of antenna becomes more difficult. It is much harder to manufacture this type of antenna in Ka band than in Ku band. We wish to get a sort of antenna whose performance is almost the same as the general slot antenna, and is easier to fabricate. Radial line slot antenna (RLSA) may be this kind of antenna.In this dissertation, a linearly polarized (LP) and a circularly polarized (CP) RLSA have been analyzed, designed and calculated. These two kinds of antennas are fed at the center of radial waveguide, where a radially outward traveling-wave mode (TEM) is generated, through a rectangular waveguide transition. Energy is radiated from the slots on the upper surface of waveguide when electromagnetic power transmits along radial direction. The reflection in input rectangular waveguide is larger for the linear polarization design than that for the circularly polarized RLSA. To suppress reflection, a metal obstacle of finite thickness is embedded in the input rectangular waveguide. The design of the circularly polarized RLSA shows rather good performances. In the course of simulation, the modeling of the antennas is a difficult part, because of its complex structure. It is solved by using VBScript.