| 摘要 |
A Doherty amplifier is described which comprises: a power splitter ( 120 ) having a first output and a second output, wherein the first output is connected to a main power splitter ( 392 ) having first and second outputs which differ in phase by 90°; and the second output is connected to an auxiliary power splitter ( 342 ) having first and second outputs which differ in phase by 90°; a main final stage amplifier ( 234 ) comprising first ( 324 ) and second ( 325 ) main paired amplifiers, the inputs of which are connected to the first and second outputs of the main power splitter ( 352 ); an auxiliary final stage amplifier ( 244 ) comprising first ( 344 ) and second auxiliary ( 345 ) paired amplifiers, the inputs of which are connected to the first and second outputs of the auxiliary power splitter ( 342 ); wherein the output from the first main paired amplifier ( 334 ) is connected to the output from the first auxiliary paired amplifier ( 344 ) by an impedance inverter ( 250 ); and the output from the second main paired amplifier ( 345 ) is connected to the output from the second auxiliary paired amplifier by an impedance inverter ( 251 ); the amplifier being arranged such that a relative phase shift is introduced to the signals input to the main and auxiliary power splitters to offset the phase shift of the impedance inverters.
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