一种高增益低噪声5.25GHz Gilbert混频器的设计

Design of 5.25 GHz Gilbert Mixer with High Gain and Low Noise

基于Gilbert单元,本文采用0.18μm CMOS工艺设计了一个工作在5.25GHz的高增益、低噪声下变频双平衡混频器.该混频器采用电流注入技术以减少流经开关管和负载的电流,缓解电压裕度和功耗的限制.采用谐振电感抑制寄生电容的充放电,减小流入寄生电容的电流,从而降低闪烁噪声.在跨导管的源极接入电感,形成负反馈电路,从而提高了电路的线性度.基于0.18,m CMOS工艺与1.8V电源电压的后仿真表明,下变频混频器具有良好的250MHz中频输出特性,电路匹配良好,测试得到的转换增益为22.65dB,输入三阶交调点为-7.66dBm,在中频250MHz处的单边带噪声系数为5.58dB,整个电路的功耗为8.64mW.

Based on Gilbert unit, this paper uses a 0. 18tLm CMOS process to design a high gain, low noise down-- conversion double balanced mixer which works in 5. 25GHz. In order to reduce the current through the switch transistor and load, and to remit the limit of voltage margin and consumption, a current injection technology is used in this mixer^A resonant inductance is used to restrain the charging and discharging of the parasitic capacitance to reduce the current which inflows the parasitic capacitance, so as to reduce flicker noise~ an inductance inserted on the source of transconductance to is form a negative feedback circuit and to improve the circuit＇s linearity. Base on 0. 18 pm CMOS process and 1.8V supply voltage, the post simulation results show that, the mixer has a good output characteristics in 250 MHz intermediate frequency and a good circuit matching, the test gets a conversion gain of 22. 65dB, IIP3 of 7. 66dBm, and SSB noise is 5. 58dB in intermediate frequency 250MHz. The power consumption of the circuit is 8. 64mW.