CONJOINED, 2.4/5-GHZ WLAN TWO-MONOPOLE SYSTEM DECOUPLED USING MODE-CONTROLLED CAPACITOR FOR NOTEBOOK COMPUTERS

A low-profile, decoupled two-monopole system with its two parasitic grounded strips conjoined, forming a very compact structure is demonstrated. Each of the two identical antennas comprises a driven coupling strip and a parasitic grounded strip, operating respectively in the 2.4GHz (2400–2484MHz) and 5GHz (5150–5825MHz) wireless local area network (WLAN) bands. The two parasitic strips are further joined together, becoming a central, grounded T monopole. By loading a capacitor between the T monopole and the antenna ground, the mutual coupling in the 2.4GHz band can be reduced by about 12 dB. The capacitor in this design is used to control Ant2 monopole mode to cancel out opposite-phased currents of the dipole mode on the T monopole when Ant1 is excited, such that isolation enhancement can be attained. The proposed two-monopole system occupies a compact size of 5mm × 40mm (about 0.04λ× 0.32λ at 2.4GHz) and is favorable for applications in the narrowbezel notebook computers owing to its low profile of 5mm.