Innovative material modulation for multilayer LTCC antenna design at 76.5 GHz in radar and communication applications

Low-cost and compact modules require appropriate multilayer substrates. In applications up to 24 GHz LTCC (low temperature cofired ceramics) tapes are successfully used but in the range from 60 to 110 GHz and especially in antenna design the high relative permittivity of LTCC is a strong constraint. In this paper a new progressive and inhomogeneous method of material modulation enabling radiation and optimising the radiation pattern by setting a calculated permittivity profile is presented for LTCC-multilayer antenna design. The method is applied to the design of a vivaldi antenna at 76.5 GHz integrated into a compact LTCC-multilayer near field radar sensor module according to Y. Venot and W. Wiesbeck (2001). By calculating the optimum permittivity profile the radiation pattern and matching have been optimised as well as the antenna size. The excellent results in the antenna design are verified and a measurement example with the radar sensor is presented.