| 摘要 |
PURPOSE:To make an irradiation area slightly different for every frequency band by setting the phase center of a primary horn to the focal point of a parabolic reflector for one frequency band, and shifting it from the focal point for the other frequency band and also selecting an angle of feeding to the reflector. CONSTITUTION:A multifrequency common-use antenna for mounting on an artifricial satellite has an offset parabolic reflector 1 fed by a multifrequency common-use primary horn 2. In a frequency band having a phase center point 8, the direction of a radiant beam of the antenna is specified without reference to an angle 4 of feeding. In a frequency band having a phase center point 9, a phase distribution in the opening surface of the reflector 1 is not vertically symmetrical in Fig. according to variation in feeding angl 4. As a result, the direction of the radiant beam of the antenna varies vertically. For this purpose, the feeding angle 4 is selected to obtain a slightly different irradiation area for each frequency band, incrasing a minimum gain in the irradiation area. |
