Study Of Mobile Terminal Multi-antenna

The 2G and 3G telecommunication systems have been widely used. The 4G is in spread and exploration all over the world. Compared with 2G and 3G, the 4G uses multiple-input multiple-output(MIMO) technique and can provide high data rate and high channel capacity. Usually, advanced smart phones work not only at 4G mode but also at 2G or 3G mode. Antennas in these multi-mode smart phones have three obvious characteristics: First, the antenna is multi-element array to realise MIMO and diversity functions. Second, the antenna is broadband or multi-band antenna to cover 2G, 3G and 4G bands. Third, high isolation between the elements of the array is necessary for the MIMO and diversity operations. The design of a multi-element, broadband and high isolation antenna array is a tough task. Paper aiming at the problems, to carry out the mobile terminal multi-antenna study. The main work is completed, including the following aspects.1 Study of the four edges layout antenna. Three kinds of antenna model were designed. Those models operate in different frequency bands. 1) The main antenna covers all the working bands. Diversity antennas covers 2300-2400 MHz band. 2) The main antenna covers all the working bands. Diversity antennas covers 1880-2690 MHz band. 3) The main antenna covers all the working bands. Diversity antennas covers 704-746 MHz and 2300-2400 MHz bands. Prototypes of the antennas were fabricated and tested. The results show that the isolation is better than 15 d B. The efficiencies are better than 40%.2 Study of the four corners layout antenna. Three kinds of antenna model were designed, such as coupled fed loop antenna, coupled fed monopole antenna and antenna with RF switch. Prototypes of the antennas were fabricated and tested. The results show that the antenna covers two wide working bands(704-960 MHz and 1710-2690MHz). The efficiencies are about 30% over the 704-960 MHz band. The isolation is about 8d B over the 704-960 MHz band.3 Study of a new hybrid decoupling structure. Based on the four-element antenna study, a lumped element and distributed parameter structure hybrid decoupling structure is presented. This structure is used in multi-antenna can realised a broadband decoupling effect. A prototype of a two-element antenna with the structure is fabricated and tested. The results show that the isolation is more than 15 d B over both the 704-787 MHz and 2200-2690 MHz bands. The isolation is about 11 d B-15 d B over both the 880-960 MHz and 1800-2200 MHz bands.