An Integrated Dual-Band Dual-Circularly Polarized Shared-Aperture Transmit-Array Antenna for K-/Ka-Band Applications Enabled by Polarization Twisting Elements

Abstract

An integrated dual-band dual-circularly-polarized (dual-CP) transmit-array (TA) antenna operating at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> - and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> -bands is proposed. Antenna-filter-antenna based polarization twisting TA cells possessing high cross-polarized and low co-polarized linearly-polarized transmission characteristics are designed. These TA cells possess highly-efficient circular-polarization transmission with flipped handedness without using any 180° phase shifting lines, thus bringing about benefits such as symmetrical structures, design simplification, and more consistent CP transmission magnitudes. In addition, the dual-band dual-CP transmissive beamforming characteristics are realized by arranging <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> - and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> -band cells in the same aperture and employing hybrid phase compensation strategy. For reducing the overall device profile, right-handed CP (RHCP) and left-handed CP (LHCP) planar arrays operating at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> - and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> -bands are fabricated as feeds for the TA. A dual-band dual-CP TA antenna with independently controllable beam directions is synthesized and experimentally demonstrated. The measured 2-dB gain and axial ratio bandwidths are 11.7% and 10.2% for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> -band RHCP and LHCP beams, and the two CP beams own bandwidths of about 7.5% at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> -band. The proposed dual-band dual-CP TA antenna can be a promising candidate for satellite communications and so on.