| 摘要 |
PURPOSE: A micro-machined tuneable filter and a manufacturing method thereof are provided to produce high resonant frequencies and high Q values and improve reliability by employing passive elements such as inductors and capacitors. CONSTITUTION: In a micro-machined tuneable filter, a voltage is given between a spiral inductor(3) and an upper electrode(5) and forms an electrostatic force used for moving the upper electrode(5) vertically. The vertical movement of the upper electrode(5) changes the capacitance between the inductor(3) and the upper electrode(5) forming a virtual variable capacitor. As shown in an equivalent circuit, an oscillating circuit is formed with a variable capacitor connected in parallel with the spiral inductor(3). Here, the change of distance between the upper electrode(5) and the bottom electrode(4) changes the capacitance of the variable capacitor and modulates the frequency. Thus, by adjusting the inductance and the capacitance, the frequency width can be controlled. |
