Unequally Element Spacing Array Antenna with Butler Matrix Feed for 5G Mobile Base Station

This In the next generation mobile system (5G mobile), multi beam base station antennas are needed. An array antenna with a Butler matrix feed circuit is one candidate. A 8 beam array antenna is developed for base station antenna. When element spacing is more than 0.7 wave lengths, a grating lobe appears at a beam far from the center beam. A grating lobe makes strong interferences to other cell. In order to decrease the grating lobes, unequally element spacing is studied. Some unequally patterns of element spacing are tried to achieve grating lobe suppression.