Radio wave transmissive cover

A radio wave transmissive cover used for a radio wave radar device configured to transmit and receive radio waves, the radio wave transmissive cover comprising:

• a base made of a plastic, the base being configured to be arranged in a path of the radio waves and having transmissiveness for the radio waves;
• and
• a conductive thin film, the conductive thin film being configured to be arranged in the path and generate heat when energized, wherein
• the conductive thin film includes square unit thin film sections that are arranged regularly,
• each unit thin film section includes
• a hole region including an annular hole,
• a conduction region located on an outer side of the hole region, and
• a patch region that is surrounded by the hole region and insulated,
• Expressions 1 to 3 hold among a radius r of the patch region, a minimum dimension c of the conduction region in a radial direction of the hole region, a width w of the hole region, a frequency frmin at which a reflectivity Kr of the radio waves is minimized, frequencies f1, f2 of edges of a band including the frequency frmin, and an index value Q related to the reflectivity Kr and a frequency band, and
• frmin
• =
• -
• 91
• 
• r
• -
• 7.2
• 
• c
• +
• 11.8
• 
• w
• +
• 113.5
• (
• Expression
• 
• 
• 1
• )
• Q
• =
• Kr
• 
• f
• 
• 
• 1
• -
• f
• 
• 
• 2
• 
• (
• Expression
• 
• 
• 2
• )
• Q
• =
• 79
• 
• r
• -
• 2.4
• 
• c
• +
• 23
• 
• w
• -
• 38.6
• (
• Expression
• 
• 
• 3
• )
• the radius r, the minimum dimension c, and the width w are determined based on Expressions 1 to 3 such that the frequency frmin is in a range from 70 GHz to 80 GHz and that the index value Q is in a range from −15 to −5.