Series-Fed Microstrip Antenna Array With Inclined-Slot Couplers as Three-Way Power Dividers

A novel approach to the design of series-fed antenna arrays has been presented, in which a modified three-way slot power divider is applied. In the proposed coupler, the power division is adjusted by changing the slot inclination with respect to the transmission line, whereas coupled transmission lines are perpendicular. The proposed modification reduces electrical length of the feeding line to 1 λ, hence results in dissipation losses´ reduction. The theoretical analysis and measurement results of the 2 × 8 microstrip antenna array operating within 10.5-GHz frequency range are shown in the letter, proving the novel inclined-slot power divider´s capability to provide appropriate power distribution and its potential application in the large antenna arrays.