| In this thesis, the applications of Left-handed Materials (LHMs) on the microstrip antennas are studied and the microstrip antennas with LHMs are designed. The main works and results are as follows:1. The basic theories of LHMs structures and single microstrip patch antenna are studied. Then the radiation characteristic, the feed mode and the impedance matching of the single microstrip patch antenna are analyzed.2. The special LHMs structures are designed and the effect of the slot, ring width, distance and the number of the DSRRs on the harmonic frequency of LHMs are discussed.3. The application of LHMs structures on the single microstrip antenna are presented in detail and the new antenna which have a periodic DSRRs substrate and cover are designed. The simulation results demonstrate that the physical dimensions of the antenna have been significantly reduced by DSRRs substrate, and can be no longer proportional to the working wavelength. Meanwhile, the directivity of antenna has been improved greatly.4. The cylindrical microstrip patch antenna and the PBG cylindrical microstrip patch antenna with LHMs are designed, and are compared with the conventional microstrip antenna.5. The designment of the impedance matching network is studied based on the principle of microstrip antenna array. The cylindrical microstrip antenna array and the PBG cylindrical microstrip antenna array with LHMs structures are designed, which are compared with the conventional antenna. The simulation results demonstrate that the gain of LHMs cylindrical antenna array has been improved compared with the conventional antenna array. |
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