Waveguide antenna with miniaturized-aperture using a split-ring-resonator

In this paper, a waveguide antenna with miniaturized-aperture using a single split-ring-resonator (SRR) is proposed. A wide bandwidth is achieved by using a single SRR and optimizing the distance between it and the ridge end. The measured bandwidth of 3.40–3.54 GHz (a fractional bandwidth of 4.03%) is much wider than that of the previous waveguide antenna using multiple rings (4.96–5.00 GHz with a fractional bandwidth of about 0.8%). The aperture of the proposed antenna was miniaturized by about 88%, and it can be utilized as a probe for near-field measurements and other applications.