Obliquely arranged feed waveguide for alternating-phase fed single-layer slotted waveguide array

An alternating phase fed waveguide array with an oblique arrangement of feed waveguide is proposed. It belongs to single-Layer waveguide arrays developed by the authors. Conventional arrays with radiation waveguides arranged perpendicularly to the feed waveguide suffer from accumulated reflection from coupling windows after round-trip propagation at the input port. In the proposed oblique arrangement, the reflections from each coupling window will not accumulate in phase but be diffused away out of phase. First, the design of obliquely arrayed T-junctions is conducted using two-dimensional finite element method (FEM). Then basic operations of the reflection canceling as well as improved voltage standing-wave ratio at the antenna input are confirmed by experiments. Almost the same radiation patterns and gain as the conventional arrays are observed in the measurements.