MIMO antennas for next generation mobile terminals

Abstract

This paper presents two MIMO antennas for 2G, 3G and 4G cellular handsets. Each antenna is meandered to form a loop structure for achieving resonance at 0.25λ and 0.5λ. The substrate used for the design is FR-4 with relative permittivity of 4.35 and loss tangent of 0.02. The overall size of the substrate is 70 × 107.5 × 0.8 mm3 with each antenna occupying an area of 50 × 10 mm2. The decoupling structure on the bottom layer of the substrate is composed of two slots etched horizontally in the ground plane. The antennas are capable of covering 2G GSM 850 (824 - 894 MHz), 2G GSM 1900 (1850 - 1990 MHz), 3G HSDPA 800 (800 - 890 MHz), 3G HSDPA 850 (814 - 894 MHz), 3G HSDPA 2100 (1920 - 2170 MHz), 4G LTE bands 1-2, 7, 30 (1920 - 2690 MHz), 4G LTE bands 5, 12-13, 17-20, 26, 28 (680 - 912 MHz), WLAN 802.11 a/b/g/n (2400 - 2480 MHz) and WLAN 802.11h (3400 - 3600 MHz). The isolation achieved between antennas is better than 12 dB in the lower and 18 dB in the upper frequency bands.