Dual-Band Circular-Polarized Ceramic Patch Antenna With Wide-Angle Axial Ratio for Direct Satellite-To-Handset Communications

In this work, a dual-band circularly polarized patch antenna is realized by using high dielectric ceramic materials and a truncated square patch design. Impedance matching is achieved by etching ring slots near the feeding probe. The proposed antenna is with the small volume of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4.62 \times 4.62 \times 4 ~\text{mm}^{3}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$10 \times 10 \times 6 ~\text{mm}^{3}$</tex> and exhibits -10 dB impedance bandwidths of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{1. 6 0 9 - 1. 6 4 0 ~ G H z}(\mathbf{1. 9 \%})$</tex> and 2.4862.500 GHz (0.6 %), covering satellite communication bands of partial <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$L$</tex> band and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$S$</tex> band, respectively. The 3-dB axial ratio bandwidths are <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1.611-1.614 \text{GHz}(0.2 \%)$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2.480-2.509 \text{GHz}\ (1.2 \%)$</tex>. The in-band total efficiencies of the lower and higher frequency bands are greater than <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-1.9 ~\text{dB}(64.6 \%)$</tex> and -1.3 dB (74.1 %), with realized gains exceeding -1.9 dBic and 0.5 dBic, respectively. Importantly, the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$3-\text{dB}$</tex> axial ratio beam widths toward the sky direction are 40° and 20° for the two operating bands. The proposed dual-band circular polarized antenna is a highly promising candidate for direct satellite-to-handset communication applications.