A Compact and Broadband Four-Way Dual Polarization Waveguide Power Divider for Antenna Arrays

The design and optimization of a novel compact and highly efficient power divider exhibiting dual-polarization in an in-phase $2 \times 4$ scheme (4-way) is presented. The two fundamental orthogonal modes $TE _{10}$ and $TE _{01}$ arrive in-phase on each of the four square waveguides for each polarization by the utilization of four 3-port turnstile junctions accompanied by four E-plane and two H-plane power division structures. The power divider ends up to two commercial waveguide (WR75) ports (each for one polarization). The presented passive component can be used as a dual-polarized feeding network for a $2 \times 2$ antenna array or any four-port radiating element with square input waveguides and aperture sizes above $2.4 \lambda $ that are commonly targeted for focal array or direct radiating elements at GEO applications. The power divider is fully metallic, a fact that makes it an ideal candidate for satellite applications. The design band is Ku-Tx (10.7–12.75 GHz), presenting a Return Loss better than 20 dB and an input-output isolation of the orthogonal modes better than 30 dB. The exciter is also subjected to sensitivity analysis for estimating its manufacturing tolerances, exhibiting a robust behavior to dimensional variations, while its losses are also evaluated around 0.1 dB when aluminum parts are assumed. Finally, a compact topology of a $2.5 \lambda $ aperture size array in a $2 \times 2$ scheme was designed and optimized where the level of aperture efficiency was the principal design goal. The array is after connected to the exciter to obtain the final feed system.