Page 189 - 2023-Vol19-Issue2
P. 189
185 | Gaid & Ali
Lso always results in the resonance crossing 56 GHz in the
third band, along with decreased return loss and bandwidth.
Therefore, the optimum value for the Lso parameter to achieve
the desired goals is 0.8 mm.
Fig. 8. Effect of the p-shaped slot position (X) on the S11
performance.
Fig. 7. Effect of slot length (Lso) on the S11 performance. taken into consideration throughout the assessment. HFSS
and CST, two well-known electromagnetic simulators, will be
E. Effect of the p-shaped slot position (X) used for this evaluation. The HFSS Simulator is used to carry
In this section, we consider the location of the p-shaped slot out the design, simulations, and optimization activities. We
with the patch’s right edge (X) and examine its impact on S11 will simulate the optimized antenna again using the CST and
performance. Figure 8 shows the consequences of changing compare the results from the two simulators to validate the
X on the proposed antenna’s S11 performance. When X is HFSS simulation results since manufacturing and measure-
set to 1.2 mm, the resonance occurs at 28 GHz with a 21 dB ment capabilities are not available in our country.
return loss. The resonance in the second band shifts to 42
GHz, although the return loss value is around 28 dB. If X is A. The reflection coefficient
increased to 1.3 mm, the resonance frequency in the second The antenna’s reflection coefficient is the ratio of reflected RF
band drops to 37 GHz, while the resonance frequencies in power to the power delivered into the antenna, expressed in
the first and third bands remain fixed. However, the return decibels (dB). A low return loss indicates efficient power trans-
loss in the first band drops to around 12.5 dB. When X is mission into the antenna, while a high return loss indicates
set to 1.5 mm, the resonance occurs at 27.8 GHz, 38.4 GHz, significant power reflection, resulting in poor antenna per-
and 56 GHz, establishing the three desired bands. If X is formance. Therefore, optimal antenna performance requires
increased to 1.7 mm, the resonance in the second band shifts low return loss. Antenna design, frequency of operation, and
to 40 GHz, although the resonance in the first and third bands impedance matching can affect return loss and should be con-
and the value of the third band’s bandwidth remain unchanged. sidered during antenna system design and evaluation.
However, the return loss values in the first and second bands
have slightly increased. Therefore, the optimum value for the The optimized design was simulated using both HFSS
X parameter to achieve the desired goals is 1.5 mm. and CST software, with results presented in Fig. 9. The an-
tenna resonates at 27.9 GHz, 38.4 GHz, and 56 GHz, with
IV. RESULTS AND DISCUSSION corresponding return losses of 15.4 dB, 18 dB, and 26.4 dB,
respectively. The antenna also has a bandwidth of 1.26 GHz
In this section, the designed antenna’s performance will be around 27.9 GHz, 1.08 GHz around 38.4 GHz, and 12.015
evaluated. A performance examination of the proposed an- GHz around 56 GHz. Overall, the optimized design has
tenna’s reflection coefficient, 2D and 3D radiation character- good performance characteristics concerning return loss and
istics, voltage standing wave ratio (VSWR), surface current impedance bandwidth, confirmed by simulation results from
distribution, antenna gain, and radiation efficiency will all be both HFSS and CST software. Generally, the simulated re-
sults show a good agreement, except for a noticeable deviation
observed at 38.4 GHz in the CST curve. At 38.8 GHz, the
S11 value did not fall below the -10 dB threshold, as shown
