Orientation study to minimise coupling effects in radiation patterns of dual-packaged compact millimeter-wave antennas

This study presents a study of different antenna orientations to minimise coupling effects in the radiation patterns of two dipole arrays packaged together on multilayer organic (MLO) substrates. These effects are evident in the various ripples found in the pattern cuts of the arrays. The substrates used in the stack-up are Rogers´ RO3003™ and ULTRALAM3850^®. The two arrays, at 57 and 80 GHz, are fed together through a T-junction. The orientations studied consist of 0°, 45° and 90°. E- and H-plane patterns were measured for all orientations. Significant interference was seen in the E-plane for the 0° orientation and H-plane for the 90° orientation. This was reduced in the 45° orientation, which yielded smoother patterns than its respective counterparts in 0° and 90° orientations. Adding 5 mm of extra distance in the configurations reduced either the amount of ripples (by 0.75 for 57 GHz and 1.75 for 80 GHz) or their average level (by 0.3 dBi for 57 GHz and 0.785 dBi for 80 GHz). The gain attained for the designs was >9 dBi and agreed well with simulated results. Guidelines for packaged antenna integration for mm-wave high speed communications based on the experiments are provided.