Omnidirectional dipole antenna with wideband and low gain variation

Abstract

This study presents an omnidirectional dipole antenna with wideband and low gain variation in the horizontal plane. The antenna is made up of two driven dipoles and two parasitic dipoles placed symmetrically on both sides of a central ground plane. The driven dipole is made up of two planar arms printed on both sides of the substrate. Two small slits on both sides of the driven dipole, a large centrally placed slit in the driven dipole, extensions on both sides of the driven dipole with different dimensions, and parasitic dipoles are introduced to greatly enhance the bandwidth and also attain a low gain variation. The fabricated antenna achieves a wide impedance bandwidth of 105.5% (1.36–4.4 GHz) for S11 ≤ −10 dB, and an average gain of 4.14 dBi with a low gain variation of 2 dB. The antenna may find applications in 2G/3G/LTE frequency bands.

A compact ultra‐wideband receiving antenna for monitoring applications

“…Major progresses have been made in bandwidth enhancement, [1][2][3][4][5][6] lowest frequency extension and size reduction. [7][8][9][10][11][12][13][14][15][16][17][18][19] A considerable amount of monopole based ultra-wideband (UWB) antennas in planar or three-dimensional (3D) form have been reported, [1][2][3][4][5][6] such as a wideband shorted planar monopole with bevel structure, 1 a low profile inverted hat monopole antenna covering an UWB from 50 to 2GHz 2 ; an eye shaped monopole antenna over a modified conical ground operating from 3 to 20 GHz 3 ; a rolled monopole antenna with 132% impedance bandwidth from 3.65 to 17.8 GHz, 4 a planar monopole with sequentially embedding rectangular notches working with an ultra-wide bandwidth from 3.9 to 21.4 GHz. 5 The monopole-based antenna structure can produce excellent wideband and omnidirectional performance.…”

“…Different techniques can be combined to reduce the antenna profile effectively while maintaining wideband performance. [7][8][9][10][11][12][13][14][15][16][17][18][19] Interesting designs have been reported, including a 3D capacitively fed monopole antenna with a circular top loading and two parasitic loops, 7 a modified inverted F-shaped antenna with a shorted rectangular top hat and two parasitic pins, 8 a top loaded taper shaped monopole antenna with shorted cross substrates, 9 a wideband low profile with a conducting body of revolution and a shorted parasitic ring 10 and a low profile tapered monopole antenna with a shorted circular top plate. 11 Dielectric or resistive loadings are applied in the UWB antenna design for some specific scenarios.…”