An electronic device may include a wireless circuit, and a coaxial cable device having an S-shaped balun segment coupled to the wireless circuit, and an antenna segment coupled to the S-shaped balun segment. The S-shaped balun segment may include a first inner conductor segment, and a first outer conductor segment surrounding the first inner conductor segment. The antenna segment may include a second inner conductor segment coupled to the first inner conductor segment, and a second outer conductor segment surrounding the second inner conductor segment and coupled to the first outer conductor segment, the second inner conductor segment extending from the second outer conductor segment.