A 79-GHz LTCC laminated waveguide to metallic rectangular waveguide transition using high permittivity material

An integrated laminated waveguide (LWG) to metallic rectangular waveguide (RWG) transition based on low temperature co-fired ceramic (LTCC) technology is presented in this paper. The transition is designed for the 76 - 81 GHz radar frequency band using a high permittivity material (∈_r = 7.4). An additional secondary LWG structure improves both impedance matching and bandwidth. The bandwidth at - 10 dB return loss is more than 5 GHz. The measurement results of the fabricated prototype agree closely with the simulation. This compact and backshort-free waveguide transition allows low-cost integration and offers the possibility of measuring E-Band radar components based on ceramic substrate.