| With the arrival of information age,wireless communication systems are constantly updated and upgraded,asking for better performance of antenna.Miniaturized multi-band or wideband antennas is not only the development trend of modern antenna,but also a new challenge.The left-handed material,as a kind of artificial composite material,can effectively improve the performance of traditional antennas because of its unique electromagnetic properties and designability,providing a new way of thinking for the antenna design.Based on the understanding and analysis of left-handed material and its transmission line form,composite right/left handed transmission line,the design of the multi / wideband characteristics of the antenna is studied in this paper.The main contents are as follows:(1)A new resonant frequency is introduced utilizing the electromagnetic resonance characteristics of the left-handed material unit structure by loading the left-handed material unit on the designed single-frequency antenna,and then the dual band characteristic of the antenna is realized.In this chapter,the resonant mode of the frequency is analyzed and the resonant modes of the two operating frequencies are different.With the overall size of the antenna unchanged,the new resonant frequency can be adjusted by changing the structure size of the left-handed material unit,and the other resonant frequency is substantially unaffected.The center resonant frequencies of the designed dual-band antennas are 2.43 GHz and 5.21 GHz,which are in the communication bandwidth of the WLAN protocol,respectively.In addition,the antenna with size of 20 mm×19.5 mm×0.8 mm,also has the advantages of miniaturization and low profile.(2)Based on the fractal left-handed material structure,a balanced left / right handed transmission line resonator is designed,and the fractal processing of the structure is helpful to realize the miniaturization of the device.Applying the structure to the antenna design and studying on the dispersion curves of the composite left / right handed transmission line resonator,it is found that the resonant bandwidth casued by multi-order resonance of the resonator and the unit self resonance are fused with each other to obtain a wide working band which is 3.5-11.3 GHz.The designed antenna was processed and tested,and the spatial radiation characteristics of the antenna were analyzed.Since the electromagnetic wave propagates along the surface of the patch,the antenna also has a terminal firing characteristic. |
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