Design Of Miniaturized And Multifrequency Ceramic Antenna

Currently, the personal communication terminals combine with more and more applications and become smaller and lighter. Therefore, less space is available for the antennas and RF devices. These factors push the miniaturization and multi-frequency to be the new wave of the terminal antenna design. Based on the summarization of the methods of antenna miniaturization and multiband technology, this paper improves and proposes three miniature ceramic antennas.The main work and the innovation of this thesis can be summarized as follows:1) LTCC based multi-layer chip antenna with central symmetric characteristic. This antenna has a double-layer meander line structure. The best feature of this antenna is its central symmetry, which makes the user unnecessary to distinguish between the antenna feed end and the antenna open end, because the structures of the antenna seen from the feed end and from the open end are totally the same. The dimensions of this antenna are 10mm*2mm*1.1mm, the bandwidth of the antenna is 134MHz and the peak gain of this antenna is about 3.3 dB.2) Interdigital coupled PIFA with ceramic dielectric load. Apart from the PIFA structure and the ceramic dielectric load, the interdigital couple is introduced to further reduce the size of the antenna. The simulation result demonstrates that, without the interdigital couple, the volume of this antenna will increase 56% in order to keep the same resonant frequency with the antenna which has interdigital coupled structure. The dimensions of this antenna are 8.8mm*3.1mm*2.5mm. The resonant frequency of this antenna is 1.575GHz. The antenna has a 100MHz bandwidth and a 3.19 dB peak gain. Finally, the antenna was tested in the playground environment and the multipath environment. The result states that the antenna can receive signals from at least 4 satellites even in the multipath environment.3) Dual band ceramic block antenna. This antenna is developed from the second antenna. Through the L shape loading on the patch, the antenna has the dual-frequency features. To make the higher resonant frequency lower, the meandered patch and capacitive loading are introduced. The size of this antenna is 8.8mm*3.1mm*2.2mm. The dual bands of this antenna cover 1.575GHz and 2.45GHz respectively. The bandwidth of the band covers 1.575GHz at which the antenna has a 3.3dB peak gain is 60MHz, while the bandwidth of the band covers 2.45GHz at which the antenna has a 0.18 dB peak gain is 44MHz.