Design Of THZ VCO Based On Ordinary BiCMOS Process

THz locates between microwave and infrared ray,and it is the only Spectral range which has not been totally researched and used.THz wave has the characteristics of penetrability,security,broadband,etc.So it has great charm in the diagnosis of diseases,military security and wireless communication systems.Many research institutes of the world pay more attention to THz communication technology so that the generation of terahertz wave becomes a hot topic.According to the present research situation,this paper mainly introduces the theoretical basis and parameters of the terahertz oscillator,and the design of the terahertz oscillator circuit module based on the standard BiCMOS technology.The terahertz oscillator circuit module is designed based on IBM SiGe 0.13?m BiCMOS process.At present,there are many kinds of structure of terahertz oscillator,including Colpitts,cross coupling,ring oscillation,push-push structure,triple push,linear superposition and so on.And these structures can extract wave from the fundamental frequency to two or three,four times of harmonic.This circuit realizes the fundamental frequency oscillation.The transistor has a higher characteristic frequency than the MOS tube,so the circuit uses the transistor as the active device.Taking phase noise performance into account,the Colpitts BJT structure is a better choice.Furthermore,the differential structure has a stronger anti-interference ability for the environment noise and power supply noise,therefore the whole circuit uses the differential Colpitts oscillation structure.At the same time,due to the parasitic effect becomes very important in the terahertz frequency circuit and the phase noise performance is also directly affected by the Q value of the inductor,the passive devices such as inductors,capacitors and key signal lines are simulated by HFSS in order to ensure the performance of the circuit and the simulation accuracy.Then the multi port S parameters is imported into Cadence to achieve hybrid simulation.The simulation results are basically equivalent to the post-simulation results of traditional circuits.The whole circuit is simulated by Cadence,the post-simulation results show that the center frequency of THz oscillator is 114.5G,the tuning range is 2G,the phase noise is-76dBc/Hz@1MHz,the output power is 5.4dBm~8dBm,the time of starting oscillation is 4ns~6.5ns,the power consumption is 2.5V*23mA.Finally,a further optimization scheme is proposed for the simulation results.