| 摘要 |
PURPOSE:To obtain a small sized impedance conversion circuit with ease of manufacture and improved design performance by reducing the length of a transmission line and adding a capacitor to the line to increase its characteristic impedance. CONSTITUTION:The length of a transmission line (coplaner line) 1 (11) in an impedance conversion circuit converting the impedance between a 1st impedance Z0 and a 2nd impedance Z1 with use of the transmission line is selected shorter than a 1/4 wavelength of the operating frequency and its characteristic impedance Z is selected to be (Z0.Z1)<1/2> or over, and both ends of the line 1 are connected to a ground conductor via characteristics 2, 5 whose capacitance is identical to each other. Through the constitution above, since the length of the line 1 is shorter than the 1/4 wavelength of the operating frequency, the impedance Z is selected to be (Z0.Z1)<1/2> or over. Thus, the impedance Z is selected to be, e.g. 51OMEGA larger than a conventional impedance of 7OMEGA and a matching circuit section of various high frequency circuits is made small without incurring characteristic deterioration. |
