A Wideband Sectoral Quasi-Yagi MIMO Antenna System With Multibeam Elements

Frequency reconfigurable Yagi‐like MIMO antenna system with a wideband reflector

“…In order to produce an inductive effect, the dimensions of the parasitic reflector(s) element(s) are optimised and kept larger than the excited driven element (in our case, the half-ring slot loop is the driven element). Similarly, the dimensions of the parasitic director(s) element(s) are kept smaller than those of the driven element in order to produce a capacitive effect [11,15]. These inductive and capacitive effects couple the electromagnetic energy between the Yagi elements and contribute to the formation of directional beams with low back-lobe radiations.…”

“…This is due to the presence of the large reflector and several director elements [7]. Therefore, designing compact Yagi-based MIMO antenna system is quite challenging, and due to this reason, few Yagi-based printed MIMO designs [8][9][10][11][12][13][14][15] have been presented so far in the literature. The designs in [8,9] presented dipole excited Yagi-based MIMO antenna systems while the ones in [10][11][12][13][14][15] presented Yagi-based directional MIMO antenna systems using loop excitation.…”

“…Slot antennas are simple in construction, rigid as they are etched out of the ground (GND) plane, and have the benefit of providing wide BW [5][6][7][8][9][10][11][12][13][14][15][16]. Although Yagi antennas are versatile in terms of their feeding techniques as well as in the selection of antennas to be used as the driven element, using slot excitation in a Yagi configuration is quite challenging.…”

“…Therefore, in order to mitigate the back-lobe radiation and to achieve a directional radiation pattern from a slot antenna excitation, several back-lobe suppression techniques were employed in the literature. Most common techniques are: using electromagnetic bandgap structures [17,18], isolated surfaces [19], inductor and resistor loading [20,21], GND plane meandering and edge serration [22,23], and using additional reflector layers in a three-dimensional (3D) configuration [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. The majority of these techniques are quite complex and occupy large size which is not suitable to be employed in the design of compact printed MIMO antenna systems.…”

Stacked frequency reconfigurable Yagi‐like MIMO antenna system

“…The operating principles of a Yagi antenna are well-known and are explained in details in [7,19]. Therefore, they are not discussed here.…”