Alternating-phase fed single-layer slotted waveguide arrays with chokes dispensing with narrow wall contacts

An alternating-phase fed single-layer slotted waveguide array consisting of only two components (a slotted plate and a groove feed structure with a choke) is proposed. Its excellent characteristics as well as mechanical advantage are demonstrated. It dispenses with the electrical contact between two components and is promising for mass production. Two key techniques are introduced. One is the slot design for suppressing the grating lobes and the analysis for evaluating the mutual coupling between slots. The other is a choke on the periphery of the feed structure to dispense with contact of the periphery. 32.4 dBi gain with 60% efficiency is measured by the choke antenna without electrical contact in 26 GHz. This is an excellent result which is comparable to the full-contacted model. Advantages of alternating-phase fed arrays for mass-production are now fully confirmed.