| 摘要 |
PURPOSE:To obviate a degradation in the transmittance of radio waves by a dielectric loss by using calcium fluoride with which a low dielectric loss tangent is surely obtd. as a material of a substrate and determining the thickness of the substrate in such a manner that the product of the thickness of the substrate and the refractive index of the substrate to radio waves in integer times of 1/2 the wavelength of the radio waves. CONSTITUTION:This light-radio wave sepn. plate is constituted by laminating multi-layered dielectric films 1 onto the substrate which allow the transmission of the microwave radio waves of the prescribed wavelength so as to impart good reflectivity to the incident light of a prescribed wavelength range. The substrate 3 of such plate is constituted of the plate material consisting of the calcium fluoride and the thickness of the substrate is so determined that the product obtd. by multiplying the refractive index of the substrate 3 to the microwave radio waves to be transmitted by the thickness of the substrate 3 is integer times of 1/2 the space wavelength of the microwave radio waves. The light-radio wave sepn. plate can reflect IR light of a 3-5mum wavelength range and allows the transmission of 16.5GHz frequency radio wave. The thickness of the calcium fluoride substrate 1 is simply required to be changed if the frequency of the radio waves of the microwave band to be transmitted changes. The degradation in the transmittance of the radio waves by the dielectric loss is, therefore, obviated.
|
