| 摘要 |
<p>A microwave element in which the impedance control is performed by using the capacitance of a FET at off state, includes an impedance control circuit for controlling the capacitance between the source and the drain of the FET at off state which is constructed by a series connection circuit comprising a diode and a capacitance, connected in parallel therewith between a source and a drain of the FET, and means for applying variable bias voltage to said diode. A microwave switch is constructed by two FETs (6, 7), two impedance control circuits for controlling the capacitance of the FETs (6, 7) at off state, an input terminal (1), and two output terminals (2, 3). A microwave switched line phase shifter is constituted by two transmission lines, with different electrical lengths, four FETs, two of them are connected in series between the both ends of the two transmission lines, respectively, impedance control circuits for controlling the capacitances of the FETs, an input terminal, and an output terminal. A microwave loaded-line type phase-shifter is constituted by a main transmission line, two loaded lines having the same electrical length connected in parallel with each other, connected with the front and rear end of the main line, impedance control circuits for controlling the capacitance of the FETs at off state.</p> |
