SIW cavity‐backed dual‐band antenna with good stopband characteristics

A dual‐band antenna with good stopband characteristics is proposed. Different from conventional antennas, two transverse slots are etched on a substrate integrated waveguide (SIW) cavity. Two half modes are excited to achieve a dual‐band operation and two non‐radiating modes, a TE 110 mode and an even TE 120 mode, are induced to generate radiation nulls. With the aid of the two radiation nulls, the stopband characteristics of the proposed design including non‐radiating gain and band‐edge selectivity are significantly improved. A fabricated prototype is measured. The measured centred frequency of two passbands is at 3.28 and 3.77 GHz, respectively. The maximum gain is about 5.2 dBi in the passbands while the minimum gain is only −18.9 dBi in the stopband. The measured efficiency is 86% in the lower passband and 75% in the upper passband but it sharply decreases to lower than 5% between 3.36–3.7 GHz.