| 摘要 |
In this high-frequency filter circuit, a fourth capacitance C4 capacitively couples a first resonator 3 to an output port 2 bypassing a first capacitance C1, a second resonator 4 and a third capacitance C3, while a fifth capacitance C5 capacitively couples a second resonator 4 to an input port 1 bypassing the first capacitance C1, the first resonator 3 and a second capacitance C2. According to this filter circuit, the first resonator 3 is directly capacitively coupled to the output port 2 by the existence of this fourth capacitance C4, while the second resonator 4 is directly capacitively coupled to the input port 1 by the existence of the fifth capacitance C5. According to the above-mentioned high-frequency filter circuit, there can easily be manufactured a high-frequency filter circuit, which is able to achieve downsizing and area saving and suitable for producing an MMIC and in which the higher region side of the passband is steeply sloped by a transmission zero, generating no parasitic passband at a frequency double that of the passband. <IMAGE> |
