Millimeter-wave microstrip-feeding broadband aperture antennas in multi-layer configuration

Two types of microstrip-feeding broadband aperture antennas in multi-layer configuration are developed in the millimeter-wave band. First, the microstrip substrate is fixed between two metal plates of a back-short waveguide and a waveguide with an aperture. Second, both the microstrip feeding-line and the back-short waveguide are accommodated in the double-layer LTCC substrate. Broad bandwidth was achieved due to the multiple resonances. The characteristics of the developed antennas were evaluated by simulations and experiments in the millimeter-wave band.