On-chip Transmission Lines And The Applications For RF Switches

With the development of modern communication technology,radio frequency circuits in the microwave and millimeter wave band have received extensive attention.On the other hand,as the CMOS process node dives into deep submicrons rapidly,the CMOS process is increasingly used in the design of radio frequency systems in the microwave and millimeter wave band.As the basic component of the radio frequency circuit,the transmission line plays a vital role in the radio frequency circuit in the microwave and millimeter wave band.In this paper,the transmission lines of different configuration using 180 nm CMOS process are studied and analyzed,and these transmission lines are used in RF switches,couplers,circulators,phase shifters to achieve miniaturization.The main research work of this article is as follows:In this paper,the spoof surface plasmon polariton(SSPP)transmission line is used as an entry point to study on-chip transmission line and its application.First of all,two types of SSPP transmission line with reduced line-width are realized using PCB technology.Compared with the conventional rectangular-grooved SSPP transmission line,these two transmission lines achieve similar transmission performance with a smaller line-width.On this basis,a SSPP transmission line on the chip is simulated using 180 nm CMOS process,and the transmission line is fed directly instead of feeding by grounded coplanar waveguide,which overcomes the shortcoming of occupying huge area of conventional feeding configuration.A multi-layered slow wave transmission line paper is designed and analysed,making full use of the multi-layer metal characteristics of the chip.The propagation constant of the multilayer slow wave transmission line proposed in this paper is much larger than that of the microstrip line at the same operating frequency,providing the basis for the miniaturization of passive devices.Then the above multi-layered slow wave transmission line is applied to branch line coupler,hybrid,phase shifter,and the simulation performance is good.Compared with the coupler realized by the microstrip line,the core area of the device realized by the multi-layered slow wave transmission line is reduced by 72%.At last,a traveling wave single-pole single-throw(SPST)switch based on the transmission line is design using 180 nm CMOS process.The main analysis method is to regard the singlepole single-throw switch in the on state as an artificial transmission line,and analyze the singlepole single-throw switch from the perspective of network transmission.The simulated results show that the isolation of the designed single-pole single-throw switch is greater than 17 d B and the insertion loss is less than 2d B.