A power sensor having a microstrip transmission line, comprising: a dielectric substrate; a strip conductor disposed on one surface of the substrate; and a ground plane conductor disposed on an opposite surface of the substrate. The power sensor includes a plurality of thermocouples extending from the strip conductor, proximal end portions of the thermocouples being thermally coupled to the strip conductor. A plurality of electrical conductors is provided, each one having a first end electrically connected to a distal end of a corresponding one of the thermocouples and a second end electrically connected to the proximate end of one of the plurality of thermocouples disposed adjacent to such corresponding one of the thermocouples. The proximal ends of the thermocouples are electrically insulated one from the other.