| Satellite communication has been widely used because of its unique advantages, and it is also heading for multiband, multi-polarization and broadband. This paper focuses on the design of duplex feeding network for satellite communication in Ka band, the specific research results are as follows:The new type of OMT presented in this paper implements the impedance-matching ntework by using several intercrossing steps and a chamfer surface. It discards the septum which is often used in traditional structure and avoids the disadvantage that the septum is easily distorted in the actual processing. By using the method of microwave network S parameter analysis and optimizing the all the size of the steps, we finally get the return loss graeter than 22 d B, very low insertion loss less than 0.15 d B and high isolation greater than 170 d B in the impedance bandwidths ranging from 17.7 to 21.2 GHz and 27.5 to 31GHz; In order to get a good Out-of-band suppression effect, the paper designs a Band-pass filter on the basis of the ridge waveguide theory in CST simulation software. Simulation results show that the single ridged waveguide band-pass filter gets an excellent out-of-band suppression effect of 40 d B in the band ranging from 24 to 31GHz; Circular polarization is used to realize the transformation from linear polarized wave to circular polarized wave. In this paper, we design a new type of circular polarization under the precondition of considering the polarization device miniaturization, which is implemented by inserting metallic diaphragms in a circular waveguide. Finally, we connect the above three devices to achieve the integral structure of the feeding network and verifying its electrical properties in ADS. |
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