Dual Circularly Polarized Array Antenna Based on Corporate Feeding Network in Square Waveguide Technology

In this communication, the design and fabrication of a Ku-band antenna array is presented for dual circular polarization, using a corporate feeding network (CFN) with orthogonal dual-mode operation. A four-way CFN in square waveguide technology is implemented to uniformly illuminate the antenna array. Each of the two propagating modes in the square waveguide excites orthogonal polarizations in the antenna. A dual circularly polarized radiating element is used for the dual-polarized array. Consequently, the link capacity can be doubled by using orthogonal polarizations in a compact and low-loss antenna system. Prototypes have been fabricated by conventional machining and they have been experimentally tested. A 90% total efficiency and matching coefficient better than -10 dB have been obtained in the frequency band between 16.5 and 17.5 GHz for the dual circularly polarized antenna. Further simulations have proven the validity of this topology for larger dual-polarized planar arrays.