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 2-D SCTL-based feeding network embedded with a dual-mode combiner is designed to establish the DPAA. A prototype of a
$4\times 4$
dual-polarized array with a three-layer dielectric substrate is fabricated for demonstration. The 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 and 38.2 dB for dual polarization in this frequency range, respectively.