Modelling of dual‐polarisation diplexers based on enhanced multiport turnstile junctions

Abstract

The modelling of waveguide diplexers working simultaneously with two dual-polarisation signals is presented in this study. The proposed network is an ortho-mode junction with six physical ports based on an enhanced multiport turnstile junction. This structure is excited at the common port coming from the antenna, by two signals at different frequency bands which are required to be discriminated into dedicated ports. The added functionality of the structure presented in this work is that each frequency band can also allocate two orthogonal polarisations (dual linear or dual circular) with a very large separation between bands (fractional bandwidth larger than 55%), using two different waveguiding concepts. The first one is based on confining the high frequencies at the centre of the axial path. The second one is just the dual, diverting the high frequencies to the outer boundaries of the axial path. The proposed structures, whose modelling and design will be addressed, are suited for low insertion loss and high-power applications, since they do not use metallic pins, irises or small waveguide sections. Moreover, as consequence of the introduced waveguiding concepts, they are very compact and short in the axial direction, which is crucial for this type of feeders in satellite applications.

Novel dual-band single circular polarization antenna feeding network for satellite communications

“…The key element of this configuration is the self-diplexed junction. This element can be designed according to different high performance configurations such as, coaxial based orthomode junctions [7], asymmetric junction with dummy loads [8] and multifrequency enhanced turnstile junctions [9], [10].…”