Compact, two‐element array with high broadside directivity

Abstract

A combination of two high directivity, electrically small, slot‐modified conducting disc‐augmented Egyptian axe dipole (EAD) antennas is investigated to achieve interesting broadside radiation properties, including a high broadside directivity and front‐to‐back ratio. Their array arrangement is guided by a simple two‐element dipole model. The parasitic conducting disc associated with each EAD antenna is modified only slightly from their original single‐element dimensions to preserve nearly complete matching to their sources, to accommodate the coupling between the two elements and to maximise the array pattern characteristics. Parameter studies lead to a final design, whose simulation results demonstrate that the two‐element array has outstanding performance characteristics, including a 9.98 dB broadside directivity, an 88.19% radiation efficiency, a 20.03 dB front‐to‐back‐ratio, a − 22.42 dB mutual coupling level, more than a 30 dB level of polarisation purity, and good impedance matching to their respective 50 Ω sources, despite each antenna being electrically small, that is, ka < 1, and the distance between the centre of each element being only slightly larger than a half wavelength.

Compact Hyper-Band Printed Slot Antenna With Stable Radiation Properties

“…It is also shown that there are frequencies at which the antenna has slightly higher peak realized gain values without the parasitic oval patch than with it. This effect indicates that the antenna without the parasitic patch is more directional at those frequencies [24]. In addition, Fig.…”

“…6 demonstrates, the E-plane pattern is monopole-like. The number of lobes increases with an increase of the frequency, which indicates that the antenna operates in higher-order modes and gets more directional as the frequency increases [4,24]. The slight asymmetry found in the experimentally-obtained E-plane patterns, especially in the lower bands, is mainly attributed to the coaxial cable contribution on the radiation characteristics.…”

Two‐element Egyptian axe dipole arrays emphasising their wideband and end‐fire radiation performance

“…A variety of approaches to realise higher directivity from small antenna systems have been considered. These include, for example, end-fire arrays [1][2][3][4][5][6], Yagi-Uda arrays [7][8][9][10][11][12], broadside arrays [13], electromagnetic band-gap structures [14], artificial magnetic conductors [15,16], Huygens sources [17] and non-Foster circuit-augmented antennas [18]. Yagi-Uda arrays [19][20][21], higher order modes [22][23][24][25] and higher permittivity dielectrics to allow the possibility of Huygens sources from overlapping electric and magnetic modes [26][27][28] have been considered, for instance, for optical nanoantennas.…”

“…Even with this variety of options, a now popular, proven and effective method to enhance the gain and FTBR values remains the arrangement of two and three antennas and/or resonators in a linear array to obtain end-fire radiation properties [1][2][3][4][5][6]. As reported previously [13], this approach can be classified into two categories on the basis of the feeding technique, that is, a driven and one/two parasitic elements combination [1][2][3][4][5][6][7][8][9][10][11][12][13] and a combination of two active elements [1,2]. It has been demonstrated that enhanced end-fire directivity is produced by significantly decreasing the separation distance between the radiating elements in either combination and properly controlling the phase difference between them [1][2][3].…”

The directivity of a compact antenna: an unforgettable figure of merit

“…These include, for example, end-fire arrays [5][6][7][8], electromagnetic band-gap (EBG) structures [9], high impedance surfaces and artificial magnetic conductors [10][11][12][13], nearfield resonant parasitic (NFRP) elements [14][15][16], nonFoster circuit-augmented antennas [17], two-element NFRP antenna arrays [18,19], and Huygens sources [20][21][22][23][24][25]. The metamaterial-inspired NFRP antenna designs have led to the realization of many performance enhancements of compact systems.…”