| 摘要 |
PURPOSE:To improve the gain of the entire antenna at each frequency band by calculating an optical length correction through the weight mean of phase errors of a primary radiator according to a function of calculated power density and modifying a curved face of a sub reflecting mirror based on the result. CONSTITUTION:The shape of a main reflecting mirror 3 and a sub reflecting mirror 2 is decided in advance based on a condition that an optical length from a primary radiator 1 to an aperture 4 of an antenna is constant. Then a power density and a phase error of a radio wave radiating from the primary radiator 1 are calculated as to plural frequencies included in a multi-frequency band at each point on the sub reflecting mirror 2 phase errors of the primary radiator 1 at plural frequencies are subjected to weighted mean value calculation based on the calculated power density function. Thus, an optical path length correction at each point of the sub reflecting mirror 2 is calculated and a curved face of the sub reflecting mirror 2A is modified based on correction data. As a result, the gain of the Cassegrain antenna system using the multi-frequency band is improved over the entire multi-frequency band. |
