A 1-to-8 Fully Modular Stacked SIW Antenna Array for Millimeter-Wave Applications

This communication presents a vertically stacked substrate-integrated waveguide (SIW) antenna array that enables different array configurations with the minimum number of SIW layers. This achievement lies in the modular feature offered by the proposed design. Specifically, four distinct array configurations can be produced with only three different designs of SIW layers. Depending on the number of SIW layers employed in the stacked antenna, the directivity in the E-plane is modified. To obtain an equal and in-phase power distribution among the array elements, H- and E-plane corporate feeding networks are efficiently implemented in each array configuration. Array configurations of one, two, four, and eight radiating layers are offered by the proposed modular array, where each radiating layer is formed by eight H-plane horn antennas. The simulated directivity for the array configurations ranges from 15.8 to 23.8 dBi and the main beam direction remains fixed along the operating frequency range. The array design has been manufactured, and an agreement between simulated and measured results is observed. The measured impedance bandwidth in all the array configurations is from 35 to 41 GHz (15.79% bandwidth) with a reduction in the E-plane beamwidth as the number of radiating layers increases.