Broad Band Microstrip Patch Antenna Based on Foam-Filled and One Open Slot on Backward of Radiating Layer

A broadband microstrip patch antenna, loaded E-U-shaped open slot on backward of radiating layer is proposed and experimentally investigated. The antenna employs a foam-filled dielectric substrate, whose dielectric constant is within the lower end of the range. The proposed antenna has been designed for electromagnetic analysis including the impedance bandwidth, reflection coefficient, radiation pattern, and antenna gain. The open slot is loaded on the back radiated layer, which is perpendicular to the radiating edge of the oblong microstrip patch component, where the symmetric line feed is se-lected. This new technique used to increase the bandwidth and the gain of antenna through increasing current path by slot location, width and length on backward of radiating Layer. The main structure in this research was a single microstrip patch antenna planar with three layers operating at two resonant frequencies 4.440 GHz and 5.833 GHz. All the simulated results are con-firmed by two packages of electromagnetism simulation. An impedance bandwidth (S11 ≤ −10 dB) up to about 41.03% and 30.61% is achieved by in-dividually optimizing its parameters. The antenna exhibits nearly stable radiation pattern with a maximum gains of 8.789 dBi and 9.966 dBi, which is suitable for Wi-Fi Band, satellite communications, and wireless presented. Whereas the results before this design that we have a proof of publication are 36.17% and 28.43%.


Introduction
With a booming period and desire in modern wireless communication applications, microstrip patch antennas have attracted much interest due to their com-patibility with printed circuits without problems, light weight, profile, and ease of fabrication [1] [2] [3] [4]. A major challenge of microstrip patch antenna design comprises its commercialization that requires wide impedance bandwidth, high efficiency and high gain along with taking care at a low price in a single design. For over a period two decades, investigators and scientists have developed several methods to increase the impedance bandwidth, high efficiency and high gain of patch antenna. One of that methods, the impedance bandwidth of the microstrip patch antenna, increases with a decrease in the relative permittivity dielectric constant (Єr) [5] [6] [7] or with an increase in the layer thickness (h) [7] [8] [9] [10]. However, there is an experiential limit on increasing the layer thickness (h), while if increased beyond 0.1 wavelength (λ0), surface-wave propagation comes out, resulting in degradation in antenna performance. The bandwidth larger than 25% is accomplished utilizing gap-coupled coplanar microstrip resonators [10]. Another conventional broad-banding technique includes the use and inserting relatively thick air-gap [11] or foam-gap substrate [12], and in addition, organizing a two or more patches antenna on different layers of the dielectric substrates in one pile (stacked) [13] to achieve wide bandwidth.
In recent years, many designs have been reported to achieve wideband patch antenna for modern wireless communication devices. That includes use of various formed slot, slit and patch like U-shape slot antenna [14] [15] [16] [17] [18], wide band E-shape patch antenna [19] [20]. However, their realizable bandwidths of these designs are below 30%. As example on that, covered dielectric layer which is separated from feed patch by air as another dielectric [21], an impedance bandwidth of 220 MHz, is achieved and gain is found as 13.4 dBi. The structure in this design is 2 by 2 microstrip patch planar array antenna using air substrate with (Єr = 1) at frequency 5.8 GHz [22]. The results show that the gain increases up to 14.63 dBi if using air substrate compared to FR-4 substrate (9.04 dBi). In another novel antenna structure which contains five substrate layers [23], the eight-element antenna array with feeding network achieved frequency band from 5.28 to 6.05 GHz 15.4% and antenna gain of 16.24 dBi. Most of the reported papers in the literature are more complexes, high-cost, and have achieved a maximum bandwidth of 30% with gain below 16.24 dBi. The proposed design is low-cost and very simple with a single patch. It has achieved gain of 8.789 dBi and 9.966 dBi at a resonant frequency of 4.450 GHz and 5.833 GHz with directivity of 9.782 dBi and 10.262 dBi and a bandwidth of 41.03% and 30.61% respectively.
In our design, the results are accomplished by a little change in the distance between the top of the printed figure (open slot) and the end edge of the patch antenna while keeping the gap of the foam layer thickness constant. This modification provided relatively greater bandwidth with perfect radiation, higher efficiency, and higher gain. In general, this technique slot location and slot width and length with foam gap cause the increase in inductance on the current path of the signal. This should increase the bandwidth of the antenna as well as the efficiency and gain. Journal of Computer and Communications

Antenna Design
The one that is most recommendable for good reception apparatus execution are thick substrates, whose dielectric steady is in the lower value enclosed to 1 since they give better they provide better efficiency, produce high gain, and increase wide band. In this paper the impedance band and the gain proposed has been improved using foam substrate where dielectric constant Єr = 1.03 has thickness 3.2 mm.
The first design, the foam substrate is inserted between the radiation layer and ground plane. The radiation layer used the Rogers_RT_Duroid5881 substrate with thickness 1.

Optimized Antenna Design
The sizes of the metallic antenna were slightly changed in order to enhance the antenna performance parameters. It is optimized from 28.8 mm to 38.2 mm in 1.0 mm increments, where the other parameters are constant. Finally, the total area of the ground plane is 80 mm × 80 mm and the total area of the patch antenna is 62.5 mm × 41.5 mm.

Antenna Design without Printed Figure and Foam Gap
Microwave office (AWR) version 2018 and Advance Design System (ADS) version 2016 were used, whereas MATLAB used to compare the simulation results.
All the results are displayed graphically and numerically, where the simulators have been utilized to acquire these outcomes. The main purpose of different algorithms simulation are to support objective decision making by means of results analysis, to enable design to safely plan their operations, and to compare favorably with present different algorithms. The results simulated a successfully to operate at specified frequencies are perfect agreement between different algorithms simulation.

Simulation Results of Patch without Foam Gap and Driven Layer
The simulated plot of reflection coefficient (S11 ≤ −10 dB) against frequency is shown in Figure 3. both. The small discrepancies between two simulated results could be attributed, because the two software's have the different logarithmic (Table 2).

Simulation Results of Patch with Foam Gap and Driven Layer
In order to fully understand the influence of the space between the top of printed figure and the edge of feed the patch (D-L) parameter, the parametric investigation was carried out by varying this parameter, while holding still existing parameters values as Section 2. This simulation was conducted using two different designs. Figure 5(a) shows the parametric effect (D-L) on the reflection coefficient (S11 ≤ −10 dB), and resonant frequencies when (D-L) parameter are varied.

The Effect of Print Figure E Shape on Power Reflection Coefficient and Resonance Frequency
The following section in Figure 5(b) shows the effect of a variable parameter (D-L), with the increase in the (D-L), the resonant frequency (FR-2) curve shifts towards lower resonant frequencies, while there is no significant change in the resonant frequency (FR-1).
AS the D-L smoothly increased, there are more amount to the fringing effects occurred, this leads to a better return loss (RL-1), whereas return loss (RL-2) has a maximum amount at D-L is equal 34mm, after that, it turn into inverse direction as shown in Figure 5(c).

Bandwidth by Taking the (D-L) as a Parameter for Patch Antenna
The distance (D-L), is varying from 28.0 mm to 29.0 mm, there is very little variation in the absolute value of the bandwidth (BW-1) and the bandwidth (BW-2). The bandwidth (BW-1) and the bandwidth (BW-2) have a rapid increase to the maximum value where the distance (D-L) has an increase from 29.0 mm to 30.0 mm, whereas the distance 30.0 mm to 38.0 mm all bandwidths are a slowly decrease as shown the result in Figure 6. A significant bandwidth is observed at distance of the printed figure beyond at 30.0 mm, it is appreciable extent. In these points of observation, the bandwidths are close to 1.821 GHz or 41.03% and 30.61%. Figure 7 shows directivities and gains Vs distance (D-L). All directivities are slowly increasing from 28.0 mm to 35.0 mm, whereas the distance at 35.0 mm to Journal of Computer and Communications

Design Antenna with Printed Figure U-Shaped The Effect of Print Figure U Shape on Power Reflection Coefficient and Resonance Frequency
The simulated plot of varied reflections coefficient (S11 < −10 dB) and resonant frequencies that obtained by effect various lengths D-L from 28 mm until 38mm is shown in Figure 8(a).

The Dissimilarity of Return Losses
The results of return loss (RL-1) very similar of the simulation of two different designs as shown in Figure 9(a) and Figure 10 were obtained, whereas, return loss (RL-2) dissimilar it's irregular, It is a balanced values with activities efficiency by a specified way of the current path that pass through the patch antenna. and 30.12% covering the (4.277 -6.061 GHz) obtained by figure-U, as shown in Figure 12, Figure 13 and Table 3.

Conclusion
In this paper, the antenna design has been simulated successfully to operate at specified frequencies through specified new technique simulated by different algorithms with perfect agreement of results, whereas, the specified frequencies