Design Of Multib Band MIMO Terminal

With the large-scale laying of the third-generation mobile communication systems and the steady development of the long-term evolution, the designs of the mobile phone antennas will face much challenge, for example, the occupied small size, low profile and multiple band operation. So, the mobile phone antennas which have the small size and multiple band operation have important value. Moreover, in order to improve the use ratio of the frequency spectrum and the communication capacity, the demand of the multiple-input and multiple-output mobile phone antennas will play important role. Generally, the occupied size of the mobile phone antenna is smaller than 15×30×5 mm3. And, the designed antennas need to cover the common operating bands of the GSM /UMTS/LTE operations.Firstly, the background and the developments of mobile phone antennas are described briefly in the paper. Based on the inherent traits of the mobile terminal, common considerations about the designs of wireless data card antennas are presented. Then, the three wide technques, including the wideband matching network technique, loading lumped elements technique and distributed elements matching technique, are discussed respectively. Furthermore, for the mobile phone designs, the used skills of Ansoft HFSS are introduced, which include building model, setuping the boundary condition and excited port, analyzing the results and optimizing the parameters.Secondly, the lumped inductor’s different effects on the input impedance for the mobile phone antenna are presented. After the theoretical analysis and optimized design, a single antenna element applied in the mobile phone is relized to cover the whole GSM850/900/DCS1800/PCS1900/UMTS2100/LTE2300 operation. In the design, two proper chip inductors are loaded in the radiating strips. To describe the designed process clearly, the operating principle and main design parameters of the proposed antenna are given and discussed.Finally, the operating principle of the slot technique, which can improve the port isolation, is also studied in the paper. Then, a MIMO mobile phone antenna covering DCS1800/PCS1900/UMTS2100/LTE2300/2500 operation is sucessfully designed. The port isolation of the proposed MIMO antenna is smaller than-15 dB, which meet the industry requirement. Besides, the strucrural parameter and the measured results of the presented MIMO antenna are analyzed to present the reliability and the usement of the MIMO mobile phone antenna.