| 摘要 |
A diode 36 is inserted in the gate biasing circuit of the active transistors 20 (9,10, figure 9) of a negative impedance converter (NIC). The diode rectifies the RF signal so that a higher DC bias current flows through the transistors 20 at higher RF signal levels, thereby reducing distortion at high signal levels while allowing lower power consumption at lower signal levels. The NIC may be used to provide a negative capacitance for cancelling the capacitance of an electrically small antenna. The negative impedance of the NIC may be programmable. A branch (figure 9) comprising resistors and capacitors may be placed across the RF ports of the NIC to enhance matching performance, linearity and stability. The diode 36 may comprise a diode-connected transistor (43,figure13). The NIC transistors may comprise BJTs or FETs. |
