通信專業(yè)畢業(yè)設(shè)計(jì)外文翻譯--新的雙頻雙極化開(kāi)槽微帶天線的設(shè)計(jì)方法-在線瀏覽
2025-07-30 15:30本頁(yè)面
【正文】 locity of light in free space， r? is the effective permittivity given by 121 1 1 0( , ) 122r yyxy x? ??? ??? ? ????? (3) and 39。 munication system (VICS), and a good simultaneous impedance matching was obtained for reflection loss values 17dB at and27dB at . Fig 3 Frequency characteristics of reflection loss Figure 4 shows the axial ratio variation with the frequency for this designed antenna. It is seen that the best value of the axial ratio is about 1dB at . Fig 4 Frequency characteristics of axial ratio Figure 5 shows the measured impedance characteristics of the antenna in correspondence with Fig 3. It demonstrated that a perturbation is set for circular polarization at lower frequency . Fig 5 Frequency characteristics of input impedance Figure 6 shows the radiation pattern of the circular polarization of the designed antenna at the lower resonant frequency . In this figure, we used the unit [dBic] for gain, which can be calculated as follows m a x / 2 011[ ] [ ] 2 0 l o g [ ( 1 ) ]102 ARG d B ic G d B i? ? ? where, Gmax[dBi] denotes the measured maximum gain in [dBi], AR is the measured axial ratio. A gain of [dBic] was found for patch antenna with circular polarization at GHz. Fig 6 Radiation pattern of circular polarization Finally, the radiation pattern of the linear polarization at the upper frequency is shown in Fig 7. This is the perturbed TM30 mode, however, because the two slots exist in the patch, the shape of the radiation pattern of the perturbed TM30 mode bees similar to that of TM10 mode. A gain of 5[dBi] was obtained for patch antenna with linear polarization at . Fig 7 Radiation pattern of linear polarization 4 Concluding remarks A novel design method for a dualfrequency patch antenna with both circular and linear polarization is presented in this paper. Two resonant frequencies are behaved by etching two slots close to the radiating edges in the rectangular patch, and the circular polarization at the lower resonant frequency is achieved by setting a perturbation segment in the patch element, and by placing the feed point on the diagonal axis. A dualfrequency antenna with both polarizations, which will be used to GPS and VICS for mobile munication, is designed by using presented method. As for measured result, it demonstrated that the designed antenna has two resonant frequency, in which one is a circular polarization with an axial ratio 1[dB] and gain [dBic] at lower frequency, and the other is a linear polarization with 5[dB i] at the upper frequency. References : [1] Long S A , Walton M D. A dualfrequency stacked circulardisc antenna [J]. IEEE Trans Antennas Propagat, 1979, A P 27: 270 273. [2] Dahele J S, L ee K F, Wong D P. Dual frequency tacked annularring microstrip antenna [J] . IEEE Trans, 1987, A P 35 (11) : 1281 1285 . [3] Wang J , Fralich R, W u C, et al . Multifunctional aperture coupled stack antenna [J ] . Electron L et t,1990, 26 (25) : 2067 2068 . [4] M irschekarsyankalD, Hassani H R. Characteristics of stacked rectangular and triangular patch antenn
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