Abstract: A collinear antenna segment is provided with a plurality of radiating elements and inter-element phasing sections arranged alternately on a singlesided elongated substrate. The segment has an operatively curved in-use configuration about a longitudinal axis running substantially along the length of the segment. In use, the inter-element phasing sections allow the radiating elements to radiate electromagnetic radiation substantially in phase over an intended range of frequencies. The segment may be arranged on a flexible substrate which can be operatively curved for insertion into a radome. Alternatively, the segment may be directly arranged on the curved inner surface of a radome.