On the Design of a 3D LTE Antenna for Automotive Applications based on MID Technology

This paper presents the design of a long-term evolution (LTE) antenna and its integration on the 3D surface of the mounting compartment of an automotive roof-top antenna, using molded interconnect device (MID) technology. In the first step the design of the planar LTE antenna is shown. This antenna provides an input matching better than 10 dB in the desired frequency band and exhibits an omnidirectional radiation characteristic in the horizontal plane. Subsequently, this antenna is bent on the surface of a roof antenna housing. The effects of geometrical mapping of the planar antenna structure to the 3D surface in terms of input matching and radiation characteristics are analyzed. Based on these findings, a conformal and optimized two antenna system is introduced and discussed. A prototype realized by MID laser direct structuring (LDS) is presented and the measured antenna performance is compared to simulation results. An excellent agreement between measured and simulated results is observed. Finally, the prototype meets the specification requirements.