Design Of THz Sub-harmonic Mixer Based On Ordinary CMOS Process

Because the terahertz wave has a unique position on the electromagnetic wave,and has a unique advantage between microwave and photonics by the spectral location.In addition,it is by far the last one which has not been fully exploited the use of the band.Because of this unique property,it has wide application prospect in the field of communication,electronic countermeasure,radar,electromagnetic weapon,astronomy,medical imaging,nondestructive testing,environmental monitoring and safety inspection.In recent years,terahertz wave communication has become one of the research hotspots,as wireless communication systems continue to develop in the direction of high frequency,high bandwidth,high integration and low cost.In the communications field,standard CMOS technology has a wide range of applications because it has more advantages,such as high integration,low cost,etc..Therefore,TSMC 65 nm standard CMOS process is used to design the terahertz sub-harmonic mixer in this paper.Firstly,the basic theory and performance parameters of the mixer are introduced according to the current research situation at home and abroad.Then,we explain the working principle of the terahertz sub-harmonic mixer with different structure and the sub-harmonics used in this paper.Then,we introduce the design of the transmission line and the matching of the output of the intermediate frequency.Finally,we design the layout of the circuit according to the source-pumped schematic diagram,and simulate the proposed layout.Because of the parasitic effect of the circuit in the terahertz frequency band,the layout design and the post-simulation become the key.In this paper,because some models in the technology library are not suitable for the terahertz band and the transmission line model is not provided in the technology library,passive devices are simulated by electromagnetic simulation,and then imported into circuit simulation software design.The circuit on-chip transmission lines and key signal lines are simulated by HFSS electromagnetic field simulation.And then,the final multiport S parameters are imported into Cadence in the form of hybrid simulation.So the simulation results obtained in this paper are more accurate.The frequency of input RF signal is 303 GHz,the input signal frequency is 152 GHz,the IF output frequency is 1GHz.The conversion loss of the sub-harmonic mixer is-34 dB,and the noise figure is 25 dB.The return loss S11 of RF end and local oscillator end is-32 dB and-20 dB respectively.The all designed parameter values meet the design requirements.And this sub-harmonic mixer can be applied to terahertz communication systems.