Keywords

1 Introduction

Microstrip patch antennas (MPAs) have gained much attention in modern-day wireless communication technology or ultra-wideband (UWB) applications owing to their significant attributes say, thin profile together with lightweight, low-cost and can also be used on any host surfaces. MPA has limitations such as limited bandwidth along with lower gain and also poor efficacy [1]. Thus, there is a great need for designing multiband antenna solely for the purpose of diminishing the number of antenna’s embedded in device by a single antenna amalgamating numerous applications frequency band [2, 3]. Several methods were presented in the past to achieve multiband with notches along with slots. A lot of papers on multiband antennas were offered in the literature. In [4], a range of papers are presented in the literature where numerous methodologies are used to accomplish improved radiation pattern, UWB, and also current distribution over the radiating elements that include coplanar waveguide fed monopole antenna utilizing a defected substrate rhombus strip bounded annular ring antenna resulting from microstrip feedline using DGS [5]. Constructing slots on the patch might also be an easy approach for designing a multiband microstrip antenna [6]. The antenna should provide for a way to minimize the substrate size in order for the antenna size to be minimized [7]. A significant amount of miniaturization has been made possible by careful and meticulous investigation of slot insertion in patch and ground of MSA antenna [9], and the patch and ground plane are shorted for the further size reduction [10,11,12,13,14,15].

This research work presented proposed antenna design resonates at 2.4 GHz. The performance of the antenna was analyzed by changing the feed position. Parameters are simulated using AN SOFT HFSS v.l3.

2 Antenna Design

Various designs for a variety of shapes small-size and wide-bandwidth of microstrip antennas are design through HFSS software. In the design process of the flat surface comprising of an infinite together with a finite ground plane, back lobes are offered for the ground plane. The blueprint structure could be executed on the infinite ground plane. An accurate value is required to plot the full structure. The value could be allotted onto three axes. The structures shape can be adjusted by altering the position value. Once the antenna design is complete, the next step is to allocate frequency sweep for the actual frequency range. If we want to utilize the antenna for specific application, the corresponding return loss along with VSWR together with radiation pattern can be acquired. For optimum antenna performance, a thick dielectric substrate with low dielectric constant is appropriate.

This offers better efficacy, greater bandwidth and also improved radiation. The elementary microstrip patch antenna is a strip conductor of size L × W and thickness hacked by aground plane. The substrate thickness is lesser on compared to the wavelength. While designing an antenna, rotation of the axis along different directions offers various antenna structures. These could be appraised using high-frequency structure simulator software (Table 1).

Table 1 Comparison with previously designed-type antennas
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  1. 1.

    Width of the Patch

$$W = \frac{C}{{2f_{r} \sqrt {\frac{2}{{\varepsilon_{r} + 1}}} }}$$
(1)
C:

Free space velocity of light.

fr:

Resonating frequency.

\(\varepsilon_{r}\):

Relative permittivity of substrate.

  1. 2.

    Effective Length

$$L_{\text{eff}} = \frac{C}{{2f_{r} \sqrt {\frac{2}{{\varepsilon_{r} + 1}}} }}$$
(2)
  1. 3.

    Effective Dielectric Constant

$$\varepsilon_{\text{reff}} = \frac{{\left( {\varepsilon_{r} + 1} \right)}}{2} + \frac{{\left( {\varepsilon_{r} - 1} \right)}}{2}\left[ {1 + 12 \frac{W}{h}} \right]^{{ - \frac{1}{2}}}$$
(3)
  1. 4.

    Patch Length Extension

$$\frac{\Delta L}{h} = 0.412\frac{{\left( {\varepsilon_{\text{reff}} + 1} \right)\left( {\frac{w}{h} + 0.264} \right)}}{{\left( {\varepsilon_{\text{reff}} - 0.258} \right)\left( {\frac{w}{h} + 0.8} \right)}}$$
(4)
  1. 5.

    Length of the Patch

$$L = L_{\text{eff}} - 2\Delta L$$
(5)
  1. 6.

    Width of the Substrate

$$L = 6h + L$$
(6)
  1. 7.

    Length of the Substrate

$$Wg = 6h + W$$
(7)

3 Geometry of the Antenna

Figure 1 gives an illustration of the rectangular-shaped microstrip patch antenna geometry. The substrate size is 60 mm × 60 mm and 1.5 mm thick. The patch is presented in a rectangular shape with an effective size of 35 mm × 18 mm. The antenna utilizes a microstrip line feeding method (Tables 2 and 3).

Fig. 1
figure 1

a Rectangular-shaped microstrip patch antenna. b Ground defected structure

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Table 2 Structural details of microstrip patch antenna
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Table 3 Structural details of different slot length and width
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4 Result and Discussion

Simulation was executed utilizing HFSS Software. Subsequent sections offer the simulation result of the proposed antenna design (Fig. 2; Table 4).

Fig. 2
figure 2figure 2figure 2figure 2figure 2

a Return loss of rectangular shape microstrip patch antenna. b VSWR of rectangular shape microstrip patch antenna. c Gain of rectangular shape microstrip patch antenna. d Directivity of rectangular shape microstrip patch antenna. e Radiation efficiency of rectangular shape microstrip patch antenna. f Impedance of rectangular shape microstrip patch antenna. g Radiation pattern at frequency 8.7 GHz. h Radiation pattern at frequency 12.3 GHz. i Radiation pattern at frequency 14.6 GHz. j Radiation pattern at frequency 16.1 GHz

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Table 4 Summary of the simulation results
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5 Conclusion

A square-shaped antenna with defected ground structure was proposed and implemented. The suggested antenna’s functional characteristics say, return loss together with its SWR along with the radiation pattern were examined. The designed antenna is resonating at 2.4 GHz. The proposed antenna’s size is 60 mm × 60 mm. The offered antenna’s size is small and meets the requirement.