The Industry & Academic Cooperation in Chungnam National University

Junghwan Han

Beomsoo Bae

An active mixer for frequency conversion used in a wireless communication system improves conversion gain and noise figure by improving switching characteristics of a mixer using a LO signal without requiring additional power consumption of an active mixer block. Further disclosed is a method for improving conversion gain and noise figure of an active mixer. The active mixer includes a switching stage for receiving a LO signal and selectively performing a switching-on/off operation for frequency conversion, a body signal generator for generating a body signal to be applied to a body of an NMOS transistor of the switching stage based on the LO signal, and a voltage controller for controlling the body signal generator to selectively apply the body signal to the body of the NMOS transistor based on to the switching-on/off operation of the switching stage to control a threshold voltage of the transistor of the switching stage.

Active mixer and method for improving gain and noise

Proposed is related to a quadrature passive mixer and a frequency down-converter for enhancing an input referred second-order intercept point (IIP2). More particularly, proposed is related to a quadrature passive mixer and a frequency down-converter for enhancing the IIP2 capable of improving the IIP2 by reducing a mismatch component of a mixer block used for frequency downconversion of a wireless communication system. Here, the frequency down-converter for improving the IIP2 according to the embodiment of the present invention includes an RF quadrature signal generator, an LO IQ signal generator, a 25% LO signal generator, an LO buffer, an I-quadrature mixer, and a Q-quadrature mixer. In addition, the I-quadrature mixer and the Q-quadrature mixer receive RF quadrature signals from the RF quadrature signal generator and selectively downconvert and output the RF quadrature signals according to the 25% duty-cycle LO signals applied from the LO buffer.

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Daejeon, South Korea

Junghwan Han