Abstract: A slot antenna includes: power-supply points; and a slot, wherein in the slot antenna, the power-supply points are arranged while interposing the slot therebetween in a shorter direction of the slot, the slot being an opening that is provided in a metal sheet constituting an outer panel of a vehicle, and a width along the shorter direction of the slot is larger in each of both end parts of the slot than in an intermediate part of the slot in a longitudinal direction of the slot.

Abstract: An antenna apparatus includes a first antenna that is arranged within a predetermined area on a dielectric substrate and receives a radio wave in a first frequency band, a second antenna that is arranged in a position within the predetermined area different from the first antenna and receives a radio wave in a second frequency band, and a third antenna that is arranged in a position within the predetermined area different from the first antenna and different from the second antenna and receives a radio wave in a third frequency band. An area of the predetermined area is smaller than a sum of a minimum rectangular area including the first antenna, a minimum rectangular area including the second antenna and a minimum rectangular area including the third antenna.

Abstract: An antenna apparatus includes a dielectric substrate, a first antenna element that is arranged within a predetermined area on the dielectric substrate and receives a first radio wave in a first frequency band, and a second antenna element that is arranged in a portion within the predetermined area in which the first antenna element is not arranged and receives a second radio wave in a second frequency band. The first antenna element is contained within a first rectangular area, and the first rectangular area is a smallest rectangle that circumscribes the first antenna element. The second antenna element is contained within a second rectangular area, and the second rectangular area is a smallest rectangle that circumscribes the second antenna element. An area of the predetermined area is smaller than a sum of areas of the first rectangular area and the second rectangular area.

Abstract: An amplifier circuit includes a first transistor, a second transistor, a first pathway and a second pathway. The first transistor amplifies an external signal that is input from outside the amplifier circuit. The second transistor amplifies a detection signal that detects a level of the external signal. The first pathway is connected between a collector of the first transistor and a base of the second transistor to supply the detection signal that is output from the collector of the first transistor to the base of the second transistor. The second pathway is connected between an emitter of the first transistor and the base of the second transistor to supply a bias voltage from the emitter of the first transistor to the base of the second transistor.

Abstract: An amplifier circuit includes a first transistor, a second transistor, a first pathway and a second pathway. The first transistor amplifies an external signal that is input from outside the amplifier circuit. The second transistor amplifies a detection signal that detects a level of the external signal. The first pathway is connected between a collector of the first transistor and a base of the second transistor to supply the detection signal that is output from the collector of the first transistor to the base of the second transistor. The second pathway is connected between an emitter of the first transistor and the base of the second transistor to supply a bias voltage from the emitter of the first transistor to the base of the second transistor.