Design And Research On RF Front-End Circuit For Vehicle Mounted Radar Receiver Operating At 24GHz

With the frequent occurrence of traffic accidents, traffic safety has attracted more and more attention. The vehicle-mounted collision avoidance radar, which is as an effective measure to prevent and reduce traffic accidents, has become a hot research topic in more and more vehicle companies. And the RF front-end for radar receiver is an important part of the vehicle-mounted radar receiving system. This paper mainly focuses on the research, design and simulation on the low-noise amplifier and mixer of the RF front-end of radar receiver operating at the frequency of 24 GHz.Firstly, the development background and research direction of the vehicle-mounted radar receiver are introduced, and then the composition, working principle and main technical index of the super heterodyne radar receiver system are discussed in detail.Next, the role and the main technical indexes of low-noise amplifier in radar receiver system are introduced in detail, and the design and simulation of the syste m are also presented. In this paper, Avago’s LNA VMMK-1225 tube is used, and LNA bias circui t chip, feedback network, RF choke circuit and the matching circuit are designed with the ADS software. The inductance and capacitance to ground are used for the design of RF choke circuit. The matching circuit is matched with microstrip line, and the input is matched with the minimal noise while the maximum gain matching is used in the output. After the adjustment of the simulation and the optimization, the low-noise amplifier satisfies the stability index, and the noise coefficient is very low, and the matching degree is fine. S11 and S22 are less than-10 d B at the frequency between 23.75 GHz and 24.25 GHz, and all the parameters in the band reach the targets. After that, the layout of the low-noise amplifier is designed, and the simulation results of S11 and S22 are both less than-10 dB.Finally, the composition, working principle and main technical indexes of the mixer are introduced in detail, and the design steps of the single-balanced mixer are defined, and the simulation design and theoretical analysis are carried out by using ADS software. The four-finger Lange coupler is used, and the simulation results show a good degree of coupling. And Chebyshev low-pass filter is also used. The matching circuit of mixer diodes is designed with the method of microst rip line matching. The mixer is tuned and optimized, and the final simulation results show that the technical parameters of the mixer reach the designed target.