Stripline-Fed Patch Antenna with Long-Term Reliable Conductive Vias

The long-term reliability of plated through holes to feed antennas or suppress unwanted parallel plate mode propagation is a key issue. The proposed structure has conductive vias formed in each substrate composing the multilayer substrate instead of through holes penetrating a multilayer substrate. This configuration improves the long-term reliability of the antenna because the aspect ratio of the conductive vias is smaller than that of the through holes. A heat cycle test of fabricated antennas demonstrates the effectiveness of the proposed structure.