通信专业毕业设计外文翻译--新的双频双极化开槽微带天线的设计方法(编辑修改稿)

通信专业毕业设计外文翻译--新的双频双极化开槽微带天线的设计方法(编辑修改稿)内容摘要：

owever the lower resonant frequency f10 will change, since the slots modify the current distribution of the TM10. Step 3 Adjust the size of the antenna element to obtain the desired lower resonant frequency. Step 4 Adjust the length and the width of the slots to obtain the upper resonant frequency f30. Step 5 Set perturbation segment and place the feed point on the diagonal axis of the antenna to obtain the circular polarization at the lower resonant frequency f10. 3 Experimental results and discussion We experimentally designed a dualfrequency patch antenna with two polarizations. Figure 2 shows the configuration of the antenna, and the specifications are listed in Table 1. In this configuration of the antenna, we extended the L edge of the patch antenna to set the perturbation segment, and placed the feed point on the diagonal axis to achieve the circular polarization. Table 1 Specifications of a dualfrequency patch antenna with two polarization GPS VICS Frequency/GHz Polarization Circular Linear Return loss 15 15 Gain 3dB ic 5dBi Figure 3 shows a measured reflection loss of a designed dualfrequency antenna fed by 50Ώ coaxial probe. From this figure, it can be observed that two resonant frequencies are achieves at desired frequencies and , which will be employed to mobile global position system(GPS) and vehicle information amp。 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 frequenci。