A New Compact Size Dual-Ports Antenna with One Port Stabilized Characteristics During Impedance Variation of the Other

In this paper we present a compact dual-port antenna with capacitive decoupling provided by a gap between the two antenna ports. The antenna size is 1 x 1 cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> on a 1.57 mm thick FR-4 substrate with a relative permittivity of 4.4. Both antenna ports are matched to the measured frequency band of [5.5 - 9.8] GHz, with magnitude of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{s}_{11}$</tex>, S22 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$S_{12}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{s}_{21}$</tex> parameters below -10 dB. The maximum measured gain and radiation efficiency are 2.4 dBi and 75.5%, respectively. Input impedance values of 0 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Omega$</tex> (CC), 25 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Omega$</tex>, 75 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Omega$</tex> and 1 l M <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Omega$</tex> (OL) are applied to the input of one port and the characteristics in terms of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{S}$</tex> parameters and radiation pattern of the other port are measured. Electrical and electromagnetic simulations are carried out and compared with measurements. Good agreement is obtained between simulations and measurements.