Design Of Mixer Circuits For Multi-mode And Multi-standard System

With the continuous development of wireless communication technology, integrating multiple communication modes on a mobile terminal is an important trend in today. It proposes new requirements for the transceiver, which requires circuits can operate in different modes. So, it can save power, area and cost. Mixers are essential core part in a transceiver. And it has great significance if we can design mixers for multi-mode and multi-standard systems. If so, we will reduce the power consumption and area of the transceiver, and so on.This thesis presents the up-conversion mixer and down-conversion mixer for multi-mode and multi-standard systems which operating frequency is 0.7～2.6GHz.This design uses TSMC 0.18 μm CMOS process. The up-conversion mixer is based on the use of pseudo-differential structure of the Gilbert cell, and in order to increase the gain and linearity, is using a complementary trans-conductance current bleeding structure. In addition, a T-type LC networks can reduce the effect of the parasitic capacitance of the LO switching pairs, and make the linearity of the high-frequency greatly improved. Simulation results show that the circuit is working at 0.7-2.6GHz, the gain of the up-conversion is 8.4～8.5dB, the IIP3 of the circuit is 13.4-14.8dBm, and NF is 19.8-20.9dBm. The down-conversion mixer mainly uses folding structure to reduce the noise figure. And the input stage uses NMOS and PMOS transistors to improve conversion gain and IIP3, and at the same time it also uses the feedback resistor to form a self-bias configuration. The simulation results show that the voltage conversion gain is 13.0～13.2 dB, input 1 dB compression point is -2.9～2.7dBm, IIP3 is of 13.1～14.2 dBm, noise figure is 11.5 dB.The results of measurement of the up-conversion mixer show the voltage conversion gain is 7.3～8.2dB, the input 1dB compression point is -3.1～-1.5dBm, ⅡP3 is 9.1～14.5dBm, and the single sideband noise figure is 19.3～20.4dB. Test results of the down-conversion mixer show that the voltage conversion gain is 13.7 ～～ 14.0dB, IIP3 is 9.8-12.7dBm, the input 1dB compression point is -3.8～-2.1dBm, and the single sideband noise figure is 8.4-9.5dB.