Thermosetting resin composition, prepreg, resin film, metal-clad laminate, printed wiring board, antenna device, antenna module, and communication device

A thermosetting resin composition comprising:

• a thermosetting resin (A);
• and
• one or more kinds of a high dielectric constant inorganic filler (B) selected from the group consisting of a titanium-based inorganic filler and a zircon-based inorganic filler,
• the thermosetting resin composition providing a chart obtained by performing a substrate visual inspection according to the following method, having a peak derived from a metal foil and a peak derived from a cured product of the thermosetting resin composition that are detected separately:
• (substrate visual inspection method)
• a metal-clad laminate including a cured product of the thermosetting resin composition and a metal foil laminated on each other is prepared, from which the metal foil is removed by etching while a part of the metal foil is allowed to remain, so as to produce a test piece having a part of a surface of the cured product of the thermosetting resin composition exposed, and the test piece is mounted on and inspected with an automated optical inspection device to provide a graph with a gray level as the abscissa and a pixel as the ordinate, in which a peak derived from the metal foil and a peak derived from the cured product of the thermosetting resin composition are detected.