Differentially Fed Dual-Polarized Antenna Array Using a Structural Composite Transmission-Line Network

This communication introduces a Ku-band differentially-fed dual-polarized antenna array (DPAA) using a structural composite transmission line (SCTL) network. The dual-polarized antenna element is excited by a new hybrid differential structure with a dumbbell slot and two L-shaped probes, which generates dual-polarized radiation with high isolation and cross-polarization discrimination (XPD). The substrate integrated waveguide (SIW) and the differential power divider based on delay microstrip line constitute the SCTL, which is directly cascaded with the SCTL-based feeding network. A two-dimensional SCTL-based feeding network embedded with a dual-mode combiner is designed to establish the DPAA. A prototype of a 4 × 4 dual-polarized array with a three-layer dielectric substrate is fabricated for demonstration. Experimental results show that the DPAA has good impedance matching and directional radiation characteristics at 13.5-14.6 GHz. The measured peak gains are better than 18.4 dBi. In addition, the isolation and XPD are higher than 37.4 dB and 38.2 dB for dual-polarization in this frequency range.