Heat sink for electronic devices

A heat sink for an electronic device, comprising a base and a plurality of fins protruding from one surface of the base,

• wherein
• the base has a length (L1) ranging from 5 mm to 300 mm, a width (W1) ranging from 5 mm to 300 mm, and a thickness (H1) ranging from 0.03 mm to 200 mm;
• each fin has a thickness (L2) of 2.0 mm or less, a width (W2) ranging from 0.5 to 2.0 times that of W1, and a protruding height (H2) of at least 3 mm;
• the average number of fins is in a range of from 0.5 to 10 per 10 mm of the base's length;
• the base is composed of one or more first polymeric films;
• each fin is composed of one or more second polymeric films;
• and
• the first polymeric films and the second polymeric films are anisotropic thermal conductive films, each independently has a volume resistivity of more than 1015 Ω·cm;
• an in-plane thermal conductivity in one direction higher than that of the orthogonal direction, and said higher thermal conductivity ranges from 10 to 100 W/m·K;
• a dielectric constant of 4 or less at 30 GHz;
• and a dissipation factor of 0.001 or less at 30 GHz;
• provided that the first polymeric films and the second polymeric films are free of fillers having a thermal conductivity of 5 W/m·K or more.