基于CMOS工艺的太赫兹振荡器

Terahertz oscillator in CMOS

在太赫兹频段,无源器件电容电感的品质因数低、电路的寄生参数以及MOS管的截止频率影响使太赫兹振荡器电路难以实现高功率输出。提出一种300 GHz可调谐振荡器,首先,采用改进的交叉耦合双推(Push-Push)振荡器结构,通过输出功率叠加的方法输出二次谐波300 GHz信号,增加了振荡器的输出功率并突破了MOS管截止频率,并通过增加栅极互连电感增加输出功率。其次,太赫兹振荡器摒弃传统片上可变电容调谐的方式,通过调节MOS管衬底电压改变MOS管的栅极寄生电容实现频率调谐,避免太赫兹频段引入低Q值电容,进一步增加了输出功率。提出的太赫兹振荡器采用台积电40 nm CMOS工艺,基波工作频率为154.5 GHz,输出二次谐波为309.0 GHz,输出功率可达-3.0 dBm,相位噪声为-79.5 dBc/Hz@1 MHz,功耗为28.6 mW,频率调谐范围为303.5~315.4 GHz。

In the THz frequency band,the low quality factor of passive device capacitance inductance,the influence of parasitic circuit parameters and cut-off frequency of Metal-Oxide-Semiconductor Field-Effect Transistor(MOSFET)make it difficult for THz oscillator circuit to achieve high power output.A 300 GHz tuning oscillator is proposed to achieve high power output.Firstly,the structure of cross coupled Push-Push oscillator is adopted to realize the second harmonic signal output of 300 GHz.Through the method of power synthesis,the proposed oscillator exports the second harmonic 300 GHz signal,which increases the output power of the oscillator and breaks through the cut-off frequency of MOSFET.The gate interconnection inductance is also adopted to increase the output power.Secondly,instead of tuning with a variable capacitor on the chip,the Push-Push oscillator modulates the substrate voltage of MOSFET to adjust the parasitic gate capacitors of MOSFET to achieve frequency tuning,further increasing the output power.The proposed push-push oscillator is fabricated in TSMC 40 nm CMOS process.By extracting the second harmonic signal and using the substrate voltage tuning technology,the proposed coupled Push-Push oscillator has a peak output power of-2.2 dBm at 309.0 GHz and achieves 303.5-315 GHz tuning range.The phase noise of the oscillator is-79.5 dBc/Hz at 1 MHz offset and the power consumption is 28.6 mW.