| 摘要 |
PURPOSE: To provide a small sized phase shifter for high frequency signal with a large variable phase for a broad band by providing a variable inductor whose Y parameter of a phase shifter admittance matrix is expressed by a specific equation. CONSTITUTION: A common gate FET 31 connects to an input terminal 16, a common gate FET 35 is connected in cascade to the FET 31 and to an output terminal 18. Then a parallel connection circuit of a resistor 20 and a variable inductor 22 comprising a voltage controlled element or the like is inserted between the FETs 31 and 35 in a shunt form. A Y parameter Y21 of an admittance matrix of the parallel connection circuit is expressed in equation to decide a phase characteristic of the phase shifter, where V1 is an input voltage, I2 is an output current, G is a gain, s=jω,ω0 is a center angular frequency and Q is a Q factor. Thus, the phase shifter is realized, in which only the phase is continuously changed with a constant amplitude even when the center angular frequencyω0 is changed by varying the inductance of the inductor 22.
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