A Wideband Aperture Efficient 60-GHz Series-Fed E-Shaped Patch Antenna Array With Copolarized Parasitic Patches

A novel series-fed E-shaped patch antenna array with copolarized parasitic patches for enhanced aperture efficiency at 60-GHz unlicensed wideband applications is proposed. The additional radiation from the inserted copolarized parasitic patches between series-fed patches improves the gain flatness remarkably as well as the gain and aperture efficiency, because of the offset resonant frequency. The four-array antenna with parasitic patches presents 0.8-dB gain flatness over the whole 57-66 GHz unlicensed band, 14.5 dBi peak gain, and 63.6% aperture efficiency while that without parasitic patches shows 1.4-dB flatness, 13.4 dBi peak gain, and 49.2% aperture efficiency, without any change in the antenna size, $6.0\times 14.7\times 0.25$ mm 2 .