基于130 nm CMOS工艺,设计了工作于K波段的双平衡下变频混频器。在传统吉尔伯特单元基础上采用电流复用注入结构,减小了开关级的偏置电流,提升了开关性能。在开关级源端引入谐振电感,消除了开关共源节点处的寄生电容,抑制了射频信号的泄露,提高了增益,减小了噪声。仿真结果表明,输入射频信号为24 GHz,本振信号为24.5 GHz,本振输入功率为-3 d Bm时,该混频器的转换增益为25.8 d B,单边带噪声系数为6.4 d B,输入3阶互调截点为-8.6 d Bm。
A double balanced down-conversion mixer working at K-band was designed in a 130 nm CMOS process.Current reuse bleeding techniques were adopted in the mixer on the basis of traditional Gilbert cells,so the biasing currents of switching pairs were reduced,and the performances of switching pairs were improved. A resonating inductor was added at the common source node of switching pairs. The added inductor was used to eliminate the parasitic capacitance at the common source node. So the RF current leakage was suppressed,the conversion gain was enhanced,and the noise figure was reduced. Simulation results showed that the mixer circuit had achieved a conversion gain of 25. 8 d B,an SSB noise figure of 6. 4 d B,and an input power of third-order intercept point of-8. 6 d Bm under an RF input signal of 24 GHz,an LO signal of 24. 5 GHz,and an LO input power of-3 d Bm.