Integrated Research And Design Of Filterand Antenna For LTE

With the rapid development of wireless communication technology, the stricter requirements of the size and performance for the RF front-end equipments, such as antennas and filters, have been proposed. The method of integrated design and optimization of filter and antenna can effectively decrease the whole size of the system and improve the whole performance of the module to meet the requirements. As the system is more complex and the spectrum is becoming more and more crowded, the use of multi-band filtering antenna has shown a great advantage especially in the long term evolution(LTE), which can effectively reduce the volume, complexity and the cost of the whole system. Under such background, the integrated design for filter and antenna has been studied deeply in this thesis. This thesis mainly includes following several parts:Firstly, the basic theory and the design process of microwave filter and antenna have been provided and reviewed. Then based on these theories, the analysis and design of parallel coupled microstrip filter and microstrip filter using stepped impedance resonator(SIR) for the D-band in the LTE have been studied for subsequent filtering antenna research work;Secondly, an integrated design method for SIR bandpass filter and printed antenna has been analyzed and studied. First of all, extracting the equivalent circuit of monopole antenna, which replaces the last resonance unit of the filter, then using comprehensive design method of parallel coupled microstrip bandpass filter to determine the calculation formula of the specific structure size of coupling unit between filter and antenna. Based on this method, a filtering antenna for the D-band in the LTE is designed and fabricated. The measured results agree with the simulation results well, which verify the validity of this theory and design method. And the improvement method is considered to relieve difficult fabrication because of the small space gapes of the coupled lines;Finally, based on the feature with the controllable parasitic passband of SIR resonator, a dual-band SIR filtering antenna working on 1.95 GHz and 2.6 GHz can be obtained by integrated design of dual-band SIR filter and broadband antenna. The simulation results show that the filtering-antenna has good isolation degree between two passbands and the directional characteristic of the radiation pattern is closed to the omnidirection, which satisfies the requirements of the design index.