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A novel low‐cost, high‐gain mm‐wave antenna has been presented. The antenna consists of a proximity‐coupled linear array with a novel feed structure which presents the idea of a segmented feedline in a series configuration below the patches creating a very wide bandwidth. The increased bandwidth is due to the manner of power coupling from the feedlines on the lower substrate to the patches on the upper substrate and back down to the next feedline. Very good agreement between simulated and measured results achieved shows that the proposed antenna structure is very efficient in achieving wideband characteristics and low sidelobe levels with conformal size. The antenna has a gain of over 13.5 dB with an HPBW of 15° ± 2° over a bandwidth of 27.5–28.5 GHz. It also exhibits a return loss below −10 dB with a bandwidth of 9% from 26.4 to 28.92 GHz.

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Peak sidelobe levels (SLL) may be reduced via amplitude control or weighting across the array aperture. Several authors have made significant contributions in detailing processes for synthesising these aperture amplitude distributions for the purpose of sidelobe‐level control. This study, however, shows the use of two amplitude‐tapering methods simultaneously with pattern multiplication to achieve desired SLL. With a target bandwidth of 1.83 to 1.85 GHz and centre frequency of 1.84 GHz, a linear array is designed, fabricated and measured. Good agreement between simulated and measured results achieved shows that the proposed amplitude weighting methods applied to the antenna structure are very efficient in achieving reduced SLL below −20 dB across the operational bandwidth with an impedance bandwidth of 7.5% below −15 dB.

This paper presents a new configuration of a slotted waveguide antenna (SWA) array aimed at the X-band within the desired band of 9.38~9.44 GHz for shipboard marine radars. The SWA array, which typically consists of a slotted waveguide, a polarizing filter, and a metal reflector, is widely employed in marine radar applications. Nonetheless, conventional slot array designs are weighty, mechanically complex, and geometrically large to obtain high performances, such as gain. These features of the conventional SWA are undesirable for the shipboard marine radar, where the antenna rotates at high angular speed for the beam scanning mechanism. The proposed SWA array herein reduces the conventional design’s size by 62% using a tapered dielectric-inset guide structure. It shows high gain performance (up to 30 dB) and obtains improvements in radiation efficiency (up to 80% in the numerical simulations) and weight due to the use of loss and low-density dielectric material.