IMPEDANCE CONVERTER CIRCUIT AND COMMUNICATION TERMINAL DEVICE

摘要

In low band, the absolute value of the impedance of a primary coil (L1) is less than the absolute value of the impedance of a capacitor (C1), so low-band high-frequency signals are propagated through a transformer (T1). Consequently, low-band high-frequency signals are impedance matched through the transformer (T1). In high-band, the absolute value of the impedance of the capacitor (C1) is less than the absolute value of the impedance of the primary coil (L1), so high-band high-frequency signals are propagated through the capacitor (C1). Consequently, high-band high-frequency signals are impedance matched in the capacitor (C1). By this means, impedance matching of a high-frequency circuit and an antenna element is performed in a wide frequency band.