无片上电感的低功耗高线性度CMOS混频器

An inductorless low power high linearity CMOS mixer

物联网设备的数量将在不久的将来得到快速增长。延长电池寿命、提高信号动态范围是物联网通信系统射频前端的主要关注点。为解决射频前端功耗和线性度的问题,提出了一种改进型的吉尔伯特混频器。相比于传统吉尔伯特混频器,该混频器在跨导级采用工作在亚阈值区的PMOS/NMOS互补结构,结合了电流复用技术和导数叠加技术,实现了功耗和线性度的折中;并采用交叉电容耦合形成负阻抗,抵消了寄生电容的影响,从而在低功耗情况下提高了线性度。基于HHNEC 0.18μm Bi CMOS工艺后仿真结果表明,该混频器在射频频率0.4～3 GHz时转换增益为6.2～7.6 d B,在2.4 GHz频率下输入三阶交调点(input third-order intercept point,IIP3)为14.96 d Bm,在电源电压为1 V的情况下功耗为1.8 m W。该混频器核心电路尺寸为460μm×190μm。与相关工作对比,该混频器具有低功耗、高线性度的特点。

The number of internet of things (IOT) devices is expected to increase rapidly in the near future. Prolonging battery life and improving signal dynamic range of RF front end of the communication system are the major concerns for IOT applications. In order to solve the problem of RF power consumption and linearity, a novel Gilbert mixer is proposed. Compared with the conventional Gilbert mixer, the proposed mixer utilizes subthreshold PMOS/NMOS complementary structure at the transconductance stage and combines the current reuse and derivative superposition technologies, realizing a trade-off between power consumption and linearity. The mixer also employs two cross-coupling capacitors to generate the negative impedance which cancels parasitic capacitance, achieving high linearity with low power consumption. Implemented in HHNEC 0.18 μm BiCMOS process, the post simulation results show that the mixer has a gain of 6.2~7.6 dB from 0.4 GHz to 3 GHz and a IIP3 of 14.96 dBm at 2.4 GHz while having a power consumption of 1.8 mW from 1 V supply voltage. The mixer core circuit size is 460 μm × 190 μm. Compared with other work, the mixer has the advantages of low power consumption and high linearity.