| 主权项 |
1. A high-frequency semiconductor amplifier comprising:
an input terminal inputted with a fundamental signal having a first frequency band and a first center frequency in the first frequency band; an input matching circuit including an input end and an output end, the input end of the input matching circuit being connected to the input terminal; a high-frequency semiconductor amplifying element including an input end and an output end, the input end of the high-frequency semiconductor amplifying element being connected to the output end of the input matching circuit, and the high-frequency semiconductor amplifying element being configured to amplify the fundamental signal; an output matching circuit including an input end and an output end, the input end of the output matching circuit being connected to the output end of the high-frequency semiconductor amplifying element; and an output terminal connected to the output end of the output matching circuit, the output matching circuit including:
a first transmission line including an input end and an output end, the output end of the first transmission line being connected to the output end of the output matching circuit, the first transmission line having an electrical length of 72 degrees or more and 108 degrees or less at the first center frequency, and characteristic impedance of the first transmission line being lower than 50Ω, which is load impedance of an external load connected in parallel to the output terminal;a second transmission line including an input end and an output end, the output end of the second transmission line being connected to the input end of the first transmission line, the second transmission line having an electrical length of 72 degrees or more and 108 degrees or less at the first center frequency, and characteristic impedance of the second transmission line being lower than the characteristic impedance of the first transmission line;a third transmission line including an input end and an output end, the output end of the third transmission line being connected to the input end of the second transmission line, the third transmission line having an electrical length of 24 degrees or more and 36 degrees or less at the first center frequency, and characteristic impedance of the third transmission line being lower than the characteristic impedance of the second transmission line;a fourth transmission line including an input end and an output end, the output end of the fourth transmission line being connected to the input end of the third transmission line, the fourth transmission line having an electrical length of 12 degrees or more and 18 degrees or less at the first center frequency, characteristic impedance of the fourth transmission line being lower than the characteristic impedance of the first transmission line, the characteristic impedance of the fourth transmission line being higher than resistance of a desired load impedance provided to the high-frequency semiconductor amplifying element at the fundamental frequency, and line width along a second direction of the fourth transmission line being 0.8 times or more and 1.2 times or less of line width along the second direction of the third transmission line;a fifth transmission line including an input end and an output end, the output end of the fifth transmission line being connected to the input end of the fourth transmission line, the fifth transmission line having an electrical length of 12 degrees or more and 18 degrees or less at the first center frequency, and characteristic impedance of the fifth transmission line being equal to the resistance of the desired load impedance provided to the high-frequency semiconductor amplifying element at the fundamental frequency; anda wire part including an input end and an output end, the output end of the wire part being connected to the input end of the fifth transmission line, and the input end of the wire part being connected to the input end of the output matching circuit. |
