| 摘要 |
PURPOSE:To obtain low-noise characteristic of a mixer having IF signal in a high G Hz band in a wide band, by setting the electric length from the earth short-circuit end of an LPF, whose terminal is grounded and short-circuited to a mixer diode, to the half wavelength of the IF signal. CONSTITUTION:A high frequency signal inputted from a waveguide 11 of a line converting circuit 9 is transmitted through a main line 2 and is applied to a mixer diode 3. A local oscillator signal inputted from a terminal 4 is coupled with the signal of the line 2 in a high frequency, and the local oscillator signal is applied to the diode 3 through a BPF5. An LPF6 is provided for the purpose of short-circuiting a terminal A of the diode 3 for the high frequency signal and the local oscillator signal in respect to high frequency, and the IF signal from the diode 3 is outputted from a terminal 8. Meanwhile, an LPF12 whose terminal is grounded and short-circuited is connected in parallel with the line 2 near a connection terminal 10 between the circuit 9 and the line 2, and the electric length from the earth short-circuited end of the LPF12 to the diode 3 is set to the half wavelength of the IF signal. |
