Design of Ortho-Mode Junction with Waffle-Iron Filters for K/Ka Band Shared Aperture Antennas

The shared aperture reflector antenna used for satellite communication requires the downlink to operate at the K and Ka frequency bands, with RHCP, and the uplink to operate at the Ka frequency band, with LHCP. The feed chain is a key component for achieving its performance. The OMJ (Ortho-Mode Junction) with 4 -arm waffle-iron filters described in this article is the core component of the feed chain. It is a design challenge to balance the performance of low-frequency signal coupling, high frequency signal insertion loss, low-pass filtering, and high-order mode suppression, especially when the K-band and Ka-band are close to each other. By using structural parameter design and optimization, waveguide mode control, and full-wave simulation analysis, the above difficult problem has been solved. The simulation results show that the performance meets the application requirements of the multi-frequency band shared aperture antenna.

I. Introduction

With the development of satellite communication, satellite remote sensing and other technologies and applications, multi-frequency shared aperture antennas have been increasingly widely used due to their advantage of reducing the number of antennas, saving layout space, and lowering construction costs. Many scholars have focused on the research of multi-frequency feed chain and frequency selective surfaces, achieving shared aperture antennas such as , Q/V, but more novel frequency combinations, wider frequency bandwidths, and better antenna performance are still need to explore. For example, the band antenna proposed in this article requires a wider frequency bandwidth than the traditional downlink/uplink antennas, and it also needs to provide three signal channels and orthogonal circular polarization. In order to ensure that the performance of the band shared aperture antenna meets the requirements, the relevant design, analysis are carried out.