| In this article, the interrelated theories about circularly polarized microstrip antenna are introduced. Firstly, the basic structure, three analysis methods and feed network of the microstrip antenna are introduced. Then, theories about the circularly polarized are also performed. Finally, several feed networks of the circularly polarized microstrip antenna are compared. Based on the theory and application mentioned above, three different circularly polarized antennas are designed.Firstly, it is necessary for circularly polarized antenna to achieve the wide impedance and axial rate bandwidths in the point-to-point and navigation systems. Thus, a wideband circularly polarized antenna is designed, which is operating from 1.1GHz to 1.6GHz. By using the bowtie radiation patch and wideband phase shifter network,the antenna achieves a wide impedance and AR bandwidth, respectively. Besides, in order to improve the gain of the antenna, the rectangular and circular rings are added around the bowtie dipoles. The antenna gain is improved from 9d B to 10.3d B.Secondly, because of the application of multi-band circularly polarized(CP) antenna, an antenna covering the WLAN/Wi MAX bands is also designed, the dual-band circularly polarized performance is achieved by embedding several L-shaped and T-shaped perturbations. To improve the unidirectional radiation pattern and gain of the antenna, a cavity underneath the antenna is added.Thirdly, due to the requirement of miniaturized CP antenna. Thus, a miniaturized circularly polarized navigation array is designed. By using the shorting pin, the antenna achieves a compact size. Finally, the dimension of the unit is 32mm*32mm*19mm, and it has a performance of the VSWR<1.5 、 AR<2d B 、 Gain>2.1d B during the 1268.52±10.23 MHz frequency band. For the array, it achieves a good performance, including VSWR<1.5、AR<2.2d B、Gain>-1.5d B. Therefore, the miniaturized circularly polarized microstrip array can be well applied to the satellite navigation. |
PDF Full Text Request