Ultra-Wideband and Low-Profile Design of Tightly Coupled Dipole Antenna

In this paper, an ultra-wideband tightly coupled dipole antenna (TCDA) unit operating at 2–18 GHz (9:1) is designed. The cell has a pass size of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5\ mm× 5</tex> mm and a profile height of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.084λL ( >λL</tex> is a low-frequency wavelength). The antenna unit eliminates short-circuit resonance points by loading a resistive frequency-selective surface (RFSS), and common mode resonance elimination is achieved by shorting the columns and lowering the dielectric constant. The antenna unit can realize an E-plane sweep angle of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">± 45∘</tex> and an Active VSWR of less than 3. At Active VSWR less than 3.5, the H-plane sweep angle <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">± 45∘</tex> .