Abstract This paper presents the design technique for a series-fed traveling-wave microstrip patch antenna array. The unique feature of this design is the employment of a notched feed patch as a radiating termination patch in combination with varying widths of radiating elements. This technique produces a low sidelobe performance. To achieve this effect, the antenna array is horizontally polarized, with measured results of -30 dB sidelobe, 4.5 degree 3-dB beamwidth, and 12 dBi gain at 39...