Patent ID: 7816970

Claim:
A low voltage frequency mixing apparatus with improved voltage gain and linearity, the apparatus comprising: a transconductor whose voltage gain is controllable, for converting a Radio Frequency (RF) signal into a current signal under control of a first bias that is self bias; a separator for transferring the current signal to a switching unit; and the switching unit for receiving a second bias and for outputting a signal having a frequency corresponding to a difference of a frequency of the RF signal and a frequency of a Local Oscillation (LO) signal by performing a switching operation according to the LO signal wherein the transconductor comprises: a first Metal Oxide Semiconductor (MOS) transistor; a second MOS transistor; and a resistor connected to a drain of the first MOS transistor and a gate of the second MOS transistor, wherein the drain of the first MOS transistor is coupled to a drain of the second MOS transistor, and a gate of the first MOS transistor and the gate of the second MOS transistor receive the RF signal, and wherein the resistor couples drains and gates of the first MOS transistor and the second MOS transistor.