Isolation of high-Q antennas for mobile handsets

Isolation, beween the antennas at low frequencies (700 MHz), is one of the major issues in 4th Generation Long Term Evolution. This paper presents a practical method to improve the isolation between the ports of Tx an Rx antennas through narrow-band antennas used in separate transmit and receive mode. Furthermore, a patented feeding technique is applied to feed the antenna, which helps improving the isolation between the antenna ports. An isolation of better than −22dB at 700 MHz, is shown to be possible to achieve, by utilizing this method.