Research On Transmitter Front-end Circuit Technology Of UWB Pulsed Radar

Ultra-Wide Band(UWB)technology is widely used in the fields of short-range and highspeed wireless communication,ground penetrating radar,through-wall imaging and medical imaging.UWB pulse radar system has unique advantages in wireless sensing,non-contact medical monitoring and object speed and position detection.Compared with traditional continuous-wave radar,it has stronger multipath resolution,higher positioning accuracy and lower power consumption.Combining with the low cost and low power consumption of CMOS technology,the research of monolithic pulse radar system mainly focuses on the fields of short-range indoor positioning,gesture recognition and other applications.However,in order to achieve penetration detection applications,it is necessary to ensure a higher output power,which will inevitably increase the power consumption of the system and there will be no advantages of low power consumption of CMOS process.Pulse waveform generation circuit and UWB power amplifier are the key modules of the UWB pulse radar transmitting front-end system.It is of great importance to study their power consumption and performance.Firstly,research status and development trend of UWB pulse radar system are introduced in this thesis.Then,the overall structure and operational principle of the existing UWB pulse radar system are described.And equivalent time sampling method which is widely used in the monolithic UWB pulse radar system is introduced.Then the time-domain waveforms,spectrum diagrams and circuits of UWB pulse waveforms are compared.A fully digital UWB pulse generation logic is innovatively proposed,which can significantly reduce the power consumption and area of the circuit.At the same time,aiming at the shortcomings of high power consumption of the power amplifier,combined with the working principle of UWB radar,an innovative switching control logic is introduced to the power amplifier.Power consumption of the overall system can be significantly reduced when the power amplifier only turns on during transmission of the pulse without degrading performance of the power amplifier.In this thesis,a 3-10 GHz UWB pulse radar transmitting front-end is designed with TSMC 65 nm 1P9M 1.2V standard CMOS technology.Simulation results show that the center frequency can be adjusted from 3GHz to 10 GHz while the pulse width is from 0.4ns to 1.2ns.Bandwidth of the signal is 1.6 GHz and transient emission power of 7.78 d Bm can be realized at 4 GHz with the power consumption of 55.24 m W when working at the repetition frequency of 10 MHz.Because of the parasitic effect,bonding inductance and loss of the PCB,measurement results show that the center frequency can only be adjusted from 3GHz to 6 GHz with the pulse width from 0.67 ns to 1.2ns.Bandwidth of the signal is 1.7 GHz.And transient emission power of 3.05 d Bm can be realized at 4 GHz.For penetration detection application,especially through-wall imaging,a 4-6GHz UWB pulse radar transmitting front-end is designed with TSMC 65 nm 1P9M 1.2V standard CMOS technology.The number of pulses selection logic and the switching logic for power optimization are introduced.Simulation results show that the carrier frequency can be adjusted from 3GHz to 8.5 GHz while the pulse width is from 0.117 ns to 1.2ns.Bandwidth of the signal is from 1.13 GHz to 4.31 GHz and the maximum transient emission power of 18.46 d Bm can be achieved at 5.8 GHz.The lowest power consumption is 51.7 m W at 10 MHz repetition frequency.The measurement results show that the carrier frequency can be adjusted from 3GHz to 5.7GHz with the pulse width from 0.28 ns to 1.2ns.Bandwidth of the signal is from 1.05 GHz to 4.55 GHz.And maximum transient emission power is 17.46 d Bm at 5.698 GHz.