Antennen für automobile Radarsensoren bei 79GHz

Abstract Antennnas for automotive radar sensors at 79GHz In this thesis low-cost planar antennas for 79GHz automotive radar systems are investigated. Considering state of the art antennas in current radar systems, two different antenna concepts are studied. First, substrate integrated waveguide slot antennas using a synthetic waveguide formed in a laminate are researched. An equivalent circuit model using precomputed fullwave simulation data is used to precisely control the exhibited radiation pattern in order to meet the automotive radar specifications for short-, mid- and longrange mode. Arrays for these ranges are manufactured using lowcost substrates in a standard PCB-process. Measurements carried out in an anechoic chamber show a high agreement with full-wave simulations. Finally, the manufactured antennas are integrated within a demonstration sensor to test their effectiveness in a real world scenario. It is concluded that this type of antenna can be used for different radar ranges and offers sufficient performance. As the second antenna type, grid array antennas are investigated. These antennas are composed of perpendicular microstrip lines forming a mesh on a substrate with continous back metallization. By shaping this mesh the aperture is formed and thus the resulting beam can be controlled. Full-wave simulations and a simple equivalent circuit model are used to develop grid antennas on a low-permittivity substrate. Single-ended and a newly differential feeding technique are studied. The differential feed is using a two-layer substrate stack with the feeding enclosed in a synthetic waveguide in the lower layer in order to avoid spurious radation. Measurements of the fabricated antennas show a good performance in the 79GHz range. An array of grid antennas with incorporated feeding network is developed for integration into the demonstration sensor.

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