Design and construction of X-band antenna for sensing satellite with the use of ring feeding probe and radiation pattern directing microstrips

In this paper, a waveguide antenna with a saddle-shaped pattern for remote sensing satellite applications has been introduced, and an efficient method to excite the antenna for circular polarization achievement has been presented. With the use of a circular microstrip probe, the mode inside the cylindrical waveguide is stimulated in such a way that the antenna has circular polarization with only one feeding input, and in addition, the input impedance of the antenna is 50 Ω. To achieve the saddle-shaped pattern, plus-shaped guides have been used. These guides are printed as microstrips on the Rogers 5880 substrate. The innovation of this article is in the simultaneous use of directional elements to create a saddle-shaped pattern and a circular probe to create circular polarization in order to design a suitable antenna for LEO remote sensing satellites. After the simulation, this antenna was fabricated and tested. The test results show that the antenna has a real gain of more than 3 dBi at angles of θ = ±65. The axial ratio of the antenna is less than 3 dB in the 8.23GHz for θ values between ±50, which shows that the antenna has a desired circular polarization in this θ angle range.