Patent ID: 9106313
Filing Date: 2015-08-11
Classification: H01F,H03H,H04B

Abstract:
1. An impedance conversion circuit for use in an antenna device that transmits and receives a high-frequency signal in a frequency band including a first frequency band and a second frequency band of which the second frequency band is higher than the first frequency band, the impedance conversion circuit comprising: a transformer that includes a primary side coil and a secondary side coil and is connected between a feeding port and an antenna port; and a first capacitor that is connected between the feeding port and the antenna port; wherein an absolute value of impedance of the first capacitor in the first frequency band is larger than an absolute value of impedance of the primary side coil; an absolute value of impedance of the first capacitor in the second frequency band is smaller than the absolute value of the impedance of the primary side coil; the primary side coil includes a first end connected to the feeding port; the primary side coil includes a second end connected to the antenna port; the secondary side coil includes a first end connected to ground; the secondary side coil includes a second end connected to the antenna port; and the first capacitor is connected between the first end of the primary side coil and the second end of the secondary side coil.