Design And Implementation Of LTCC Miniaturized Multi-band Antenna

With the high development of communication technology, the fourth generation mobile communication system technology(4G) has come into commercialization stage. So it is necessary to design a kind of antenna with small size, good radiation performance, and multi-band. LTCC antenna with its small volume, good performance, not easy to be damaged, has attracted many scholars in recent years. In this dissertation, the author designs two antennas with different structure by the techniques of LTCC. The main task of this dissertation is as follows:1. The development of LTCC antenna in recent years is introduced at first. Then the author introduces some basic technical indicators of antenna, highlighting the antenna miniaturization as well as some methods to achieve multi-band, which prepares theoretical guidance for the later chapters.2. Based on the advantage of LTCC and structure of annular wire, a multi-band LTCC antenna suited for GSM900, DCS1800, TD-SCDMA and TD-LTE is proposed. The detail design process of antenna is presented in this dissertation, including: realization of each band, bandwidth expanding of low frequency band, further reduction of reflection coefficients and measurement error analysis. By adding an annular wire at a distance of 0.1mm at the bottom of the antenna, a dual-band antenna is achieved. To achieve a tri-band antenna, another branch is added at a distance of 0.1mm at the top of the antenna. The top and bottom strips are connected by a metal column. The bandwidth of LTCC antenna has been expanded through adding a resonant branch, because it can form a mixed resonance with one of former branch. Through adding a piece of metal at the feeding surface, the reflection coefficient of antenna falls clearly. The simulated reflection coefficient of antenna is lower than-6d B in each band. The measured radiation patterns, gains and reflection coefficients are within the range of error. The whole size of antenna is only 17.8mm×6mm×0.8mm.3. Based on the structure of helix-meander line, through adding some coupling pieces in the antenna, a multi-band LTCC antenna is achieved. The effects of meander line, number of helix turns, cross-sectional of helix and the location of coupling pieces are all studied. The results suggest that the number of helix turns and locations of coupling pieces have a big effect of resonate frequency. The whole size of antenna is 16m×5mm×1.2mm. The reflection coefficient of GSM900 is lower than-7.5d B, while TD-SCDMA and TD-LTE is lower than-10 d B.