Compact Dual‐Wideband Shared‐Aperture Antenna

A compact low‐profile shared‐aperture antenna with dual‐wideband operation is proposed. A monopole, which embeds a rectangular slot in the center, is fed by a microstrip line to generate an ultra‐wide lower frequency band. When a T‐shaped microstrip line is used to feed the rectangular slot in the monopole, a wide higher frequency band is extra generated, while maintaining the same antenna size. By using this new scheme, a dual‐wideband shared‐aperture antenna is designed. A prototype of the proposed antenna with a size of 0.42 λ L × 0.33 λ L × 0.002 λ L ( λ L is the free‐space wavelength at the lowest operating frequency) is fabricated and tested. Measured results show that two wide impedance bandwidths of 119.2% (0.83–3.28 GHz) and 51.4% (4.34–7.35 GHz) are achieved. Owing to the advantages of the simple single‐layer‐substrate structure, compact size and dual wide operating bandwidths, the proposed antenna is potentially useful for wide coverage of sub‐7 GHz wireless communications.