Novel planar reconfigurable circularly polarized complementary antenna for unidirectional end‐fire radiation

Abstract

In this article, a novel planar reconfigurable circular polarization (CP) complementary antenna for unidirectional end‐fire radiation is proposed. Its radiator is the combination of a shorted quarter wavelength patch and an electric dipole, which provide the vertical and horizontal polarizations, respectively. By adding a 90° phase delay line, the proposed antenna radiates CP electromagnetic waves in the unidirectional end‐fire direction. Four p‐i‐n diodes are also inserted at joints of the electric dipole and the phase delay lines, and two orthogonal CP states, left‐hand (LH) and right‐hand (RH) CPs, can be switched. In order to reduce the number of DC bias lines, electric dipole arms on both sides of the substrate are connected by metal via‐holes, which simplifies the DC bias lines. The proposed antenna at 2.45 GHz is designed and fabricated. Its measured impedance bandwidth with |S11| < −10 dB and 3‐dB axial ratio bandwidth are 2.1% and 10.7%, respectively. Additionally, its maximum half power beamwidth in xoz plane is 196°. Reasonable agreement between the measured and simulated results validates the polarization reconfigurability of the proposed antenna.

Wideband low‐profile endfire circularly polarized antenna using mode superposition technique

“…1,2 Amid the many different types of CP antenna designs, the endfire CP antennas have been applied in many applications such as radiofrequency identification (RFID), 3 fifth-generation mobile communication, 4 and wireless local area network (WLAN) applications. 5 The magneto-electric dipole [4][5][6][7][8][9][10][11][12][13][14][15] can be used to design a planar endfire CP antenna by the parallel combination of an electric dipole and magnetic dipole. 4,5,[9][10][11][12][13][14][15] The orthogonal arrangement of magnetic dipole [16][17][18] can also be used to design an endfire CP antenna.…”

“…5 The magneto-electric dipole [4][5][6][7][8][9][10][11][12][13][14][15] can be used to design a planar endfire CP antenna by the parallel combination of an electric dipole and magnetic dipole. 4,5,[9][10][11][12][13][14][15] The orthogonal arrangement of magnetic dipole [16][17][18] can also be used to design an endfire CP antenna. In these configurations, the virtual magnetic dipole is formed by the three-sided closed cavity with an open aperture, and its IBW is very small compared to the electric dipole.…”

“…Therefore, planar endfire CP antennas with IBW of up to 6.5% have been reported. 5,[9][10][11][12][13] In papers, 14,15 the IBW of the endfire CP antenna is enhanced by increasing the profile and reducing the relative permittivity of the substrate. However, the reduction in relative permittivity will increase the planar dimension of the antenna.…”

“…In these configurations, the virtual magnetic dipole is formed by the three‐sided closed cavity with an open aperture, and its IBW is very small compared to the electric dipole. Therefore, planar endfire CP antennas with IBW of up to 6.5% have been reported 5,9–13 . In papers, 14,15 the IBW of the endfire CP antenna is enhanced by increasing the profile and reducing the relative permittivity of the substrate.…”