Dual Circularly Polarized Broadside Beam Metasurface Antenna

• Published in: IEEE transactions on antennas and propagation Vol. 64; no. 7; pp. 2944 - 2953
• Main Authors: Tellechea Pereda, Amagoia, Caminita, Francesco, Martini, Enrica, Ederra, Inigo, Iriarte, Juan Carlos, Gonzalo, Ramon, Maci, Stefano
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.07.2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antennas; dual polarization; Frequency conversion; Impedance; leaky waves; left-hand circular polarization (LHCP); metasurfaces (MTSs); Modulation; right-hand circular polarization (RHCP); Surface impedance; Surface waves; surface waves (SWs); Tensile stress
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2016.2562662

This paper presents the design of a modulated metasurface (MTS) antenna capable to provide both right-hand (RH) and left-hand (LH) circularly polarized (CP) boresight radiation at Ku-band (13.5 GHz). This antenna is based on the interaction of two cylindrical-wavefront surface wave (SW) modes of transverse electric (TE) and transverse magnetic (TM) types with a rotationally symmetric, anisotropic-modulated MTS placed on top of a grounded slab. A properly designed centered circular waveguide feed excites the two orthogonal (decoupled) SW modes and guarantees the balance of the power associated with each of them. By a proper selection of the anisotropy and modulation of the MTS pattern, the phase velocities of the two modes are synchronized, and leakage is generated in broadside direction with two orthogonal linear polarizations. When the circular waveguide is excited with two mutually orthogonal TE11 modes in phase-quadrature, an LHCP or RHCP antenna is obtained. This paper explains the feeding system and the MTS requirements that guarantee the balanced conditions of the TM/TE SWs and consequent generation of dual CP boresight radiation.