Small-size LTE700/2300/2500 antenna and high-isolation antenna array using the same for the laptop computer

Small-size LTE700/2300/2500 antenna (9 × 45 mm²) and high-isolation antenna array using the same for the laptop computer are presented. The two antennas are mounted along the top edge of the supporting metal plate to be disposed on the inner surface of the upper cover of the laptop computer. Improved isolation (measured S₂₁ better than -30 dB in the LTE700 band and -26 dB in the LTE2300/2500 bands) between the two antennas is easily achieved by adjusting the supporting metal plate to have a length of about 110 mm in the longitudinal direction to the antenna array. The high isolation is obtained because the length is close to a quarter-wavelength of a frequency in the LTE700 band, which makes the excited surface currents in the supporting metal plate stronger in the longitudinal direction and hence causes weaker surface currents flowing along the top edge of the supporting metal plate. This behavior leads to high isolation of the LTE antenna array in this study.