Very-Low-Profile, Triband, Two-Antenna System for WLAN Notebook Computers

A very-low-profile, two-antenna system formed by combining two identical monopole antennas with a decoupling inductor is presented. The two-monopole design was capable of operating in the 2.4 GHz (2400–2484 MHz), 5.2 GHz (5150–5350 MHz), and 5.8 GHz (5725–5825 MHz) wireless local area network bands and yet merely occupied a small size of 5 mm × 42 mm (about 0.04λ × 0.33λ at 2.4 GHz). The two antennas symmetrically facing each other were closely packed with 1 mm spacing and required almost no separation distance. An inductor connecting the open ends of the two monopoles was employed to reduce the mutual coupling in the 2.4 GHz band. Over the 5.2/5.8 GHz bands was good isolation achieved by the devised arrangement of the antenna current nulls of higher order resonance. Owing to its low height of 5 mm, the two antennas can fit in the current narrow bezel of the notebook display.