Traveling-wave design of cross-junction power-dividers for two-dimensional microstrip planar array with 45-degree polarization in submillimeter-wave band

In the design of two-dimensional microstrip antennas, comparing with the end feeding, the center feeding has advantages of wide frequency bandwidth due to decreasing long line effect and low loss due to the shorter length of the feeding line. However, the area of center feeding circuit forms no radiation area around the center, which causes growing sidelobes. A two-microstrip-output waveguide-transition is developed to realize two-dimensional planar array composed of only one piece of substrate. To reduce no radiation area at the center, eight steps of cross-junction with a two-way power divider at the termination are designed by travelling-wave operation. The simulated performance of the designed two-dimensional microstrip planar array with 45-degree polarization in submillimeter-wave band is evaluated in this paper.