Design of a 2.4 GHz High-Performance Mixer with Current Bleeding Topology

The important characteristics of a mixer including high conversion gain, low noise, high dynamic range, low third-order intermodulation distortion and low unwanted leakage signals between ports have reconsidered. A double balanced Gilbert-cell with a class-A amplifier bleeding mixer (DBGC CAAB mixer) is designed and implemented. The voltage gain of 14 dB at class-A amplifier is used to magnifier the local oscillator (LO) signal. Current of class-A amplifier is injected into the Gibert mixer as a bleeding current to improve the performance of the trans-conductor stage. The DBGC CAAB mixer achieves a conversion gain of 17.5 dB at -14 dBm LO power, and the noise figure is suppressed from 45 dB to 10.7 dB. It is important to stress that the new configuration has a third-order intermodulation (IIP3) at -9 dBm which is considered to be insignificant. The DBGC CAAB mixer is implemented by using 0.18-mu m RFCMOS technology and operates at the 2.4 GHz ISM application with 10 MHz intermediate frequency. The power consumption is 12 mA at 1.5 V supply voltage.