Page 117 - IJEEE-2023-Vol19-ISSUE-1

Neamah, Al Sabbagh, & Al-Rizzo | 113

Reflection Coefficient(dB) RO(0 Degree) As shown in figure 4, we modelled the suggested design's
0 RO(28 Degree) 2-D radiation patterns at five of the most modern usable
frequencies: 4, 5.5,10, 24, 28, and 38 GHz. In figure 4 (a),
RO(46 Degree) the suggested design shows an “8” pattern shape at low
frequencies and a near-to-omnidirectional form at high
-10 frequencies on the y-z-plane, while in figure 4(b), the
x-z-plane pattern resembles that of a near-to-omnidirectional
-20 form at low frequencies and near to “8” shape at high
frequencies.
-30
B. 1×2 MIMO Antenna Configuration Analysis
-40
In this part, S-UWB-MIMO antennas are presented to
3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 achieve the polarization diversity principle by two identical
sector-shape monopole patch antennas set orthogonally, as
Frequency (GHz) shown in figure 5. The MIMO antenna is a compact shape of
45×23×1.6 mm3, where the nearest separation between
Fig. 3: Reflection coefficients versus frequency for different adjacent patches is ?0/11, where ?0 is calculated at 3.6 GHz at
values of sector shape monopole (SSM) rotation angles free space. The antenna is optimized by using the Computer
(RO). Simulation Microwave Studio (CST MWS) software. First,
it will refer to the sector patch state, either right or left side
8 Gain (dB) y-z plane 4 GHz orientation depending on the arc position for its front view.
5.5 GHz The patches are enumerated as 1 and 2; as shown in figure 5,
0 0 10 GHz patch 1 is said to be the left layout, whereas patch 2 is the
-8 300 330 30 24 GHz right layout. We investigated all cases of patch antenna
28 GHz layouts to get better isolation between antenna elements.
-16 210 150 60 38 GHz Figure 6 depicts four scenarios of impedance bandwidth
180 (S11&S22<-10) and isolation (S12 and S21) versus
-24 270 90 frequency, which depends on the cases of MIMO elements
-16 (a) alignments. As shown in Figure 6 (a), for right-right
120 configuration, the isolation reaches 15.6 dB and 17 dB of
-8 bands (9.3-13.5) GHz and (19.3-25.6) GHz, respectively,
240 while the impedance bandwidth of S11&S22<-10 is between
3.6 to 40 GHz, again this isolation is not satisfied the MIMO
0 optimal result. When the right-left configuration is
considered, as shown in figure 6 (b), the isolation is confined
8 between (9.3-13.5) GHz and (19.3-25.6) GHz, which have
less than 20 dB. The impedance bandwidth of S11&S22<-10
Gain (dB) x-z plane is between 3.6 to 40 GHz, except S11 is notched at 7 GHz;
again, this result does not satisfy good MIMO criteria. As
shown in Figure 6 (c), for the left-left configuration, the
frequency region 8.8 to 20.4 GHz has an isolation of less
than 20 dB; once again, this isolation does not meet the
criteria for MIMO. When the left-right configuration is
considered, as shown in figure 6 (d), the isolation is more
than 20 dB over the impedance bandwidth of (3.6-40) GHz.

d˜ !!/11

21

(b) Fig. 5: Orthogonal two element MIMO antenna.

Fig. 4: Simulated gain of proposed super UWB single patch
antenna at frequencies 4, 5.5, 10, 24, 28, and 38 GHz (a) y- z
plane (b) x-z plane.