A Design Of Ultra-wideband Narrow Pulse Generator

Ultra-wideband narrow pulse technology uses narrow pulse transmissions with pulse widths of nanoseconds or picoseconds to exchange data.It is one of the hottest physical layer technologies for short-range,high-speed wireless networks.It is widely used in military and civilian fields.It has the advantages of high transmission speed,large bandwidth capacity,small size and low power,good coexistence and confidentiality,and is suitable for short-distance communication.In the ultra-wideband narrow pulse system,the narrow pulse generator is one of the most important key technologies.In this paper,because ultra-wideband narrow pulse technology is widely used,it was decided to explore and design a pulse generator that generates ultrawideband narrow pulses using a simple microwave device,and to make the generated narrow pulse have a relatively narrow pulse width was tried.This paper first studied the characteristics of ultra-wideband narrow pulses,including three common narrow pulse waveforms and their spectrum,power spectral density-Gaussian and various orders of derivative function pulses,raised cosine pulses,multi-period pulses.The advantages and disadvantages of these three kinds of narrow pulses and the way to optimize Gaussian pulses were introduced,and how to design appropriate ultra-wideband narrow pulses that can be used to transmit information according to the actual application scenario was analyzed.This article next studied how to make circuits to generate ultra-wideband narrow pulses,including the use of transistors to generate ultrawideband narrow pulsed circuits-TD,avalanche triodes,SRDs,and a detailed analysis of the physical characteristics of various devices and the principle of their typical narrow pulse generation circuit was also studied.This paper focused on the characteristics,working principle,and commonly used equivalent circuit model of step recovery diodes,and optimizing the equivalent simulation model of SRD.Next,This article used the ADS two-port network equivalent component to draw the simulation of the above optimization model,and after testing and optimizing the model,a step-recovery diode narrow pulse generation circuit using this model was designed,and UWB was successfully generated.The above pulse generating circuit device is easy to obtain,simple in structure,and low in cost.In view of the pursuit of very narrow pulse width,this paper next studied the nonlinear transmission line technology.This paper focused on the characteristics of reducing the pulse width of the nonlinear transmission line—dispersion and loss.The reason why the nonlinear transmission line can sharpen the pulse edge was analyzed.The delay time of the NLTL was deduced,and the factors of NLTL loss generation were analyzed in detail.The way to reduce the loss were proposed.This article finally chose to use the microstrip line NLTL to design the actual circuit,with reducing the ultra-wideband narrow pulse width generated by the above step recovery diode.After that,according to the parameters of the Rogers 4003 dielectric board.This article matched impedance,simulated the layout,and used Altium Designer to complete the circuit board drawing.Finally,the circuit was processed and soldered,and the circuit was actually tested to get the proper pulse.