| 摘要 |
A variable impedance matching circuit 104 between the RF power amplifier 102 and the antenna 103 is adjusted to obtain a low DC current drain in the RF amplifier. The DC current drain may be sensed by a resistor 100, or, if the RF signal is pulsed, by a transformer. The arrangement avoids losses which would be present in conventional designs using two matching circuits, one matching the amplifier output to 50 Ohms and the other matching the antenna to 50 Ohms. A wide impedance matching bandwidth may be achieved. The variable impedance matching circuit 104 may use a variable capacitor or inductor, or a capacitor array switched by MEMS devices. |
