A Compact Quad-Band Shared-Aperture Antenna Based on Electromagnetic Transparent Structure

A compact quad-band shared-aperture antenna is proposed for wireless communication in this letter. The antenna is designed by integrating a dual-band patch antenna working in lower frequency bands and a dual-band shared-aperture substrate integrated coaxial slot array antenna working in higher frequency bands into a common radiation aperture. The dual-band patch antenna is located above the dual-band shared-aperture antenna, and an air interlayer is introduced in the middle. Through shape and discretization design, the dual-band patch antenna can radiate waves in the lower bands and is electromagnetic transparent to waves in the higher bands. The dual-band shared-aperture antenna can radiate waves in the higher bands into free space and is almost unaffected by the dual-band patch antenna. Quad-band shared-aperture performance is, thus, achieved. The gains of the antenna are 7.4–7.7, 9.8–10.4, 17–18.5, and 18.7–19.5 dBi over working bands 2.55–2.62, 4.74–5.24, 26.5–27.4, and 37.4–38.6 GHz, respectively.