Design and Integration of Millimeter-Wave 5G and WLAN Antennas in Perfect Full-Screen Display Smartphones

Smartphone industries are seeking to maximize screen size, but a perfect full-screen phone is not yet available due to the unoccupied area required for the mobile antennas. Since a touchscreen is coated with transparent conductive layers, antennas below the touchscreen cannot create outward radiation. Accordingly, a non-metallic area is left for the antennas, which reduces the screen size. In this paper, we propose a design and integration of antennas for future millimeter-wave 5G smartphones to suit a perfect full-screen display. The proposed design consists of three modules, including a 1 x 12 patch antenna array at 28 GHz, a 1 x 8 patch array at 38 GHz, and a loop antenna at 2.45 GHz. The design environment consists of fully metallic top and bottom enclosures, mimicking the touchscreen and the printed circuit board, respectively. The three antennas were implemented on the flanks. Although the design area was limited and contained in parallel conductive plates, the three antennas still provided broad impedance bandwidths (26.5-32.0 GHz, 35.2-42.0 GHz, and 2.41-2.48 GHz) and high gains (16.7 dBi, 16.4 dBi, and 4.3 dBi). The isolation was larger than 20 dB, and the scanning ranges were +/- 45 degrees. The proposed scheme is the first antenna system designed for perfect full-screen display phones.