Abstract: A radio communication apparatus transmits a transmission signal amplified by a first amplifier via a circulator and amplifies a received signal received via the circulator by a second amplifier. The radio communication apparatus includes: a controller that outputs control information based on a signal level between the first amplifier and the circulator; and a phase shifter that is provided between the circulator and the second amplifier and adjusts a phase of a reflected wave generated from an input side of the second amplifier based on the control information.

Abstract: An amplification device includes a first amplifier configured to amplify an input signal in accordance with a first gate voltage, and a second amplifier configured to amplify the input signal in accordance with a second gate voltage, wherein at least one of the first gate voltage and the second gate voltage are controlled on the basis of a current ratio of a first drain current of the first amplifier to a second drain current of the second amplifier.

Abstract: An amplifier includes a voltage detector that detects current flowing to a drain terminal of a transistor which amplifies a signal using GaN as a voltage difference by means of voltage conversion, a compensation decision unit that decides whether or not to perform gain compensation based on the voltage difference detected by the voltage detector, and a gain compensation unit that performs the gain compensation according to the voltage difference when the compensation decision unit decides to perform the gain compensation.

Abstract: A circuit board for reducing a transmission loss and a method for manufacturing the circuit board. In the circuit board including a ground layer and power layer facing each other, a wiring layer disposed between the ground layer and the power layer, and an insulating section formed between the ground layer and the power layer so as to sandwich the wiring layer therebetween, a low dielectric loss layer having a dielectric tangent lower than that of the insulating section is formed at least on an upper or lower surface of the wiring layer. According to such a circuit board, the low dielectric loss layer is formed on an interface between the insulating section and the wiring layer, and therefore, a transmission loss in a high frequency region is reduced.

Abstract: An amplifier includes a voltage detector that detects current flowing to a drain terminal of a transistor which amplifies a signal using GaN as a voltage difference by means of voltage conversion, a compensation decision unit that decides whether or not to perform gain compensation based on the voltage difference detected by the voltage detector, and a gain compensation unit that performs the gain compensation according to the voltage difference when the compensation decision unit decides to perform the gain compensation.

Abstract: A circuit board for reducing a transmission loss and a method for manufacturing the circuit board. In the circuit board including a ground layer and power layer facing each other, a wiring layer disposed between the ground layer and the power layer, and an insulating section formed between the ground layer and the power layer so as to sandwich the wiring layer therebetween, a low dielectric loss layer having a dielectric tangent lower than that of the insulating section is formed at least on an upper or lower surface of the wiring layer. According to such a circuit board, the low dielectric loss layer is formed on an interface between the insulating section and the wiring layer, and therefore, a transmission loss in a high frequency region is reduced.

Abstract: The circuit board comprises a through-hole via which is formed in a through-hole passed through a substrate and includes a via portion electrically connected to a part of a plurality of interconnection layers at the inside wall of the through-hole and a pad portion formed on a surface of the substrate in a region surrounding the through-hole and is connected to the via portion. In the circuit board, an opening is formed for passing through the through-hole via out of connection with a constant-voltage interconnection layer in the region where the through-holes is formed. The constant-voltage interconnection layer is the interconnection layer nearest to the pad portion, and an outer diameter of the pad portion is larger than a diameter of the opening formed in the constant-voltage interconnection layer, whereby a capacitor including the pad portion and the constant-voltage interconnection layer as a pair of electrodes is formed.