| A multi-resonant design approach to broaden the beamwidth and bandwidth is advanced by combing the theory of multi-resonant circular sector patch antennas and self-balanced magnetic dipole antennas.Based on the self-balanced and multi-resonant theory,this thesis proposes a dual-band stacked antenna with E-plane wide beamwidth and stable gain at both bands.The main contents of this thesis include:1.Based on the background of balanced feed,the impact and traditional solutions are explained.According to the principle of self-balanced,the circular sector magnetic dipole antenna introduces a quarter-wavelength rectangular parasitic element to convert the unbalanced current into a useful current to achieve balanced feed.Compared with the microstrip square patch antenna,it is verified that the self-balanced principle can effectively expand the beamwidth.2.To verify the correctness of the principle,a self-balanced sector magnetic dipole antenna with operating frequency of 2.45 GHz and flared angle of 180°,a circular sector patch is stacked on top layer of the circular sector magnetic dipole to form a dual-band stacked antenna.Based on the theory of multi-resonant,two symmetrical rectangular slots are cooperated on the sector patch to excite its higher-order mode and achieve dual-band characteristic.The optimal values of the design parameters are analyzed by simulation of software and the antennas are made.Finally,the correctness of this design method is verified by the comparison of experimental measurement and simulation.3.According to the theoretical method of dual-band stacked antenna,the resonant frequency at low band can be adjusted by various radius of the self-balanced magnetic dipole.A dual-band stacked antenna with an operating frequency of 3.5 GHz is designed and the dual-band ratio of the stacked patch antenna can be changed with various radius of the lower layer magnetic dipole.The designed antennas are made and measured to verify the validity and correctness of the design method. |
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