Research Of Millimeter Wave Monopulse Antenna Based On Substrate Integrated Waveguide

Monopulse radar antenna can receive all the direction information and distance information by a single pulse cycle, which has the advantages of high positioning accuracy and strong anti- interference ability and has been widely used in missile terminal guidance system. In order to satisfy the special requirements of the platform, it is often required that the ideal monopulse antenna has small volume, light weight and easy integration.A new type of guide wave circuit based on substrate integrated waveguide(SIW) is proposed in recent years. SIW takes advantages of low cost, light weight, compact structure and easy integration with other active and passive circuit. It combines the characteristics microstrip circuit and rectangular waveguide, which has been used in the design of low profile microwave devices.Combination of SIW technology and planar slot array antenna technology in this paper, a millimeter wave monopulse antenna system with low profile, light weight, low side lobe level(SLL) and high gain is put forward. The overall size is 80mm×144mm×1.088 mm.The design results show that the gain of 27.82 dB,the sum beam SLL of-29 dB in the elevation plane, and the SLL of-24 dB in the azimuth plane. Here are the detail researches as follo ws:1: In order to realize low side lobe level performance in the elevation plane, two back-to-back 16 slots antenna with Taylor distribution method is designed. Firstly, the theoretical researches of the transmission characteristics of SIW and design method of standing wave slot array are carried out; then, parameter optimization design procedure is finished based on the previous theory, and the one dimensional slot array design parameters are presented. The simulation results show that the gain of 18.23 d B,the SLL of-30.2dB in the elevation plane sum beam. Besides, in order to receive the sum and difference beam in the elevation plane and azimuth palne, the 8 slot antennas with the same design parameters are united into the whole antenna array to simulate.The results are as follows: the maximum gain of 27.82 d B, the SLL of-29 dB in the elevation plane sum beam, and the SLL of-13.2dB in the azimuth plane.2: In order to realize low SLL performance in the azimuth plane, Eight-way power divider network with Taylor distribution is designed based on SIW. Firstly, a 8-way uniform power divider network is designed in the paper; Then, the T-junction and Y-junction power divider with different power output is analyzed. Based on the above design process, adjusting the relative position of inductance in the current branch and the corner to make the power of the all output ports meet Taylor distribution and have the same phase. Then, Combination the network with the array antennas to simulate, the result indicates that the network can effectively reduce the SLL of sum beam in the azimuth plane. Compared with uniform power subsystem, the SLL is reduced 11 d B.3: To feed the radition antenna to form the sum and difference beam, SIW monopulse comparator is designed. Designing the directional couple,phase shifter and the transition between SIW and rectangular waveguide. The return loss of all ports are below-25 dB. The amplitude inconsistency is less than 0.6dB, and The phase inconsistency is less than 3.9deg. Besides, combing of the need of the project, using the design methods to design a new monopulse comparator to match another monopulse antenna based on cassette structure.4: Completing the integration of millimeter wave monopulse antenna system; Processing and testing the monopulse comparator and transition section structure; At the same time, testing the early process monopulse slot array antenna with uniform feed to verify the one dimensional linear array method.There are three characteristics in this paper. First, the conventional approach is to use the same power output to design SIW multichannel power network. It is the first time that SIW power divider network using Taylor distribution to design to realize low SLL performance of antenna in the azimuth plane.Second, when designing the SIW monopulse comparator, the tranditonal test method is to use the transition between SIW and microstrip line. A new transition structure between SIW and waveguide is used in the SIW monopulse comparator. The structure reduces the insertion loss of comparator.Third, the whole antenna is presented in this paper using Taylor distribution in the elevation plane and the azimuth plane.The sum beam SLL of antenna is reduced in the two plane...