| 摘要 |
PROBLEM TO BE SOLVED: To prevent the occurrence of wrinkles on an antenna film due to the time changes caused by time passage a temperature or the like and to adjust the characteristics, after the assembly of an antenna by installing plural slits in a dielectric. SOLUTION: A planar antenna 5 formed of a base plate 1, an antenna film 3, a radome 4 and dielectrics with slits 10 is used. Since extension/contraction are absorbed in a slit part, even if the sponge-like dielectric whose thermal expansion coefficient is large is extended/contracted by temperature, wrinkles do not occur in the adjacent antenna film 3 by cutting a slit in the dielectric 10. In the setting method of the width of the slit and the number of slits, the extension/contraction length of the dielectric whose thermal expansion coefficient is larger than that of the antenna film 3 is calculated, and slit width and the number of slits, which can cover extended/contracted length, are obtained. Thus, deterioration of characteristics such as gain, beam width and side lobe of the antenna can be prevented.
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