Design and Simulation of High Performance Rectangular

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GSJ: Volume 8, Issue 8, August 2020 ISSN 2320-9186


GSJ: Volume 8, Issue 8, August 2020, Online: ISSN 2320-9186
Design and Simulation of High Performance
Rectangular Microstrip Patch Antenna Using CST
Microwave Studio

1st Md Ziaur Rahman Dept. Civil Engineering Dhaka International University
Dhaka,Bangladesh [email protected]

2nd Mohammed Mynuddin Dept. Electrical and Computer Engineering
Georgia Southern University Statesboro, GA, USA
[email protected]

Abstract—The Microstrip patch antenna has become very famous and has attracted much attention towards the research because of its light weight, compact, inexpensive and are capable of maintaining high performance over a wide range of frequencies are preferred. In this paper, the rectangular patch is designed with different parameters like return loss, VSWR, directivity along two directions, radiation pattern in 2-D and 3-D, smith chart , impedance matching are simulated using CST Microwave Studio simulation software. The microstrip patch antenna is designed to increase the bandwidth and return loss. FR-4 with dielectric constant of 4.3 is used as a substrate for the proposed antenna. The designed rectangular microstrip patch antenna with inset feed technique is very useful for various applications in Industrial, Scientific and Medical sectors which operates at 3GHz range. It shows the return loss of -37.08dB and 6.652 dBi gain at the resonating frequency of 2.946 GHz. The inset feed and slot improve the impedance matching and return loss of the antenna.

fed to symmetry around the middle line, thus reducing the excitation of undesirable modes. For improved performance feeding line will have the impedance equal to patch impedance characteristics.A microstrip line was fed to the patch antenna Linked to the point inside of the patch where the impedance to the input is 50Ω. The patch may be square, rectangular, circular, triangle and elliptical but the most commonly used microstrip patch antenna is the rectangular microstrip patch antenna [1]. The basic outline of the antenna is depicted in Figure 1, where W is the width, and L is the length (relative to the feed point)[7]. In the simplest structure, L = W = λeff /2,

Index Terms—Patch antenna,Return loss,Gain, Directivity,CST MWS

The microstripe patch antenna consists of a small Metallic patch over a large metallic ground layer.A dielectric sheet known as substratesupports the patch.Using printed circuit board technology, the patch is usually etched on the dielectric substrate. That’s why a microstrip patch is also referred to as Printed Antennas .The performance of patch depends on its size and shape. A microstrip patch can be fed either by a microstrip transmission line or co-axial transmission line. The microstrip line can be etched in a single process, together with the patch.A recess in the patch is generated to reach the correct Impedance point on the patch.The recess depth is calibrated to match the impedance. A patch antenna fed with a coaxial transmission line has an input bandwidth of around 2 to 4 percent. A single patch antenna provides 6-9db for the maximum directive gain. An inherent advantage of patch antenna is its ability to have diversity of polarization. Using multiple feed points or a single feed point with asymmetric patch configurations, patch antennas can be ideally built to have vertical, longitudinal, right hand circular polarization RHCP or left hand circular (LHCP) polarization.The patch normally

Fig. 1. Basic structure of a microstrip patch antenna.
which means an constant ( r) of the substance between the patch and the conductive surface (substrate) below which causes the shortening effect. The patch of antenna is a thin metal strip mounted on the ground plane under which the thickness of the metal strip is limited by t << λ0 and the height is restricted by 0.00330 < h < 0.0530 to reduce the fringing effect and analyzed the range of dielectric constants are usually high i.e. in the range of 2.2 < r < 12 [2-3].
The most important three parameters considered for constructing a Microstrip patch antenna are given below [4]:
• Frequency of operation (f0): The antenna has been designed between the range of 2-4 GHz and 3.0 GHz is the default resonant frequency exclusive for this research arrangement.

GSJ© 2020

GSJ: Volume 8, Issue 8, August 2020 ISSN 2320-9186
• Dielectric constant of the substrate r: Dielectric constant is one of the most important parameters in the Microstrip antenna and substrate is used. One of the most used materials is FR4, but it only supports the 2-4 GHz range. FR4 PCB is also not capable of handling high power at microwave frequencies. Its permittivity is 4.3.
• Height of dielectric substrate (h): Antennas used in phones are expected to be light in weight and small in size, which restricts their height. By substituting c = 3108m/s, r = 4.3 and f0 = 3GHz, the values of antenna dimensions can easily be determined. The following equations are used in designing the patch antennas [45]:




Value Unit

Resonant Frequency (fr)

2.946 GHz

Substrate Width (Wg)

61.38 mm

Substrate Length (Lg)

47.36 mm

Patch Width (W)

30.69 mm

Patch Length (L)

23.68 mm

Length of the inset(Fi)

7.53 mm

Length of the Microstrip transmission line

12.056 mm

Dielectric constant of substrate ( r)

4.3 mm

The height of the dielectric substrate (h)

1.6 mm

The height of the conductor (t)

0.035 mm

The width of Microstrip feed line (Wf)

3.137 mm

The gap between the patch and the inset-fed (Gpf) 0.512 mm

A. Return Loss and Real Power:

Fig. 2. Inset feed microstrip patch antenna.

• Calculation of the width(W): W =



( r +1) 2

• Calculation of effective dielectric ref f = r2+1 + r2−1 × [ 1+W12h ] 21

constant( reff ):

Fig.-3 shows that the antenna is resonating at 2.946 GHz. Return loss is the simplest way to describe the input and output of the signal sources or when the load is not matched or not all the available generated power is delivered to the load [8]. The parameter S11 has been calculated for the proposed antenna and the results of the simulated return loss are shown in Fig.3.The value of return loss has been found as -37.08dB which is very good. In figure 4 describes the different real

• Calculation of extension



W h


reff +0.03)






W h




• Calculation of effective length (Leff ):Leff )= 2f0√c reff • Calculation of actual length of patch (L): L = Leff −
• Calculation of ground plane dimensions (Lg and Wg): Lg = 2L, Wg = 2W
• Calculation of Length of the Microstrip transmission line [5]: T L = λ4 = 4√λ0 r
The dimensions of the antenna design used in this work are
shown in Table-1:

Fig. 3. Simulated return loss curve
power for this proposed antenna.The power losses in the metals is 0.00835..W and accepted power is 0.499...W. Fig.5 shows the efficiency of the designed antenna in dB.

The Microstrip patch antenna is designed and simulated using CST. This program analyzes the 3D and multilayer configurations in general forms.It have been commonly used for the design of different antenna types.It may be used to calculate and plot the return loss, standing wave ratio from Smith charts, Real power Vs Frequency, VSWR, E-field and H-field distribution, gain as well as radiation patterns.

Fig. 4. Real power vs frequency

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GSJ: Volume 8, Issue 8, August 2020 ISSN 2320-9186


Fig. 5. Efficiency of the proposed antenna
B. Voltage Standing Wave Ratio (VSWR): The calculation of impedance mismatch is Known as VSWR
(Voltage Standing Wave Ratio)[9]. The VSWR ratio of proposed antenna is found as 1.028 as shown in Fig.6, which should lie in between 1 and 2.

Fig. 8. H-field Distribution of the designed Antenna at 3GHz

Fig. 6. VSWR at resonant frequency of 2.946 GHz
C. Bandwidth From the figure- the antenna bandwidth was calculated by
using this formula [5]: Bandwidth:= √ff11−×ff22 × 100%. The value of f1 and f2 are taken at −10dB and the bandwidth of the designed is obtained 3.68%.
D. E-field, H-field,Power flow and surface current Distribution

Fig. 9. Power flow of the antenna at of 3GHZ

Fig. 7. E-field Distribution of the designed Antenna at 3GHz

Fig. 10. Surface current distribution of the designed Antenna at 3GHz
E. 3-D Far-Field Radiation Pattern for Directivity and Output Gain
• Gain: Gain is a very important parameter of every antenna. Basically, the gain is the ratio of the radiated field

GSJ© 2020

GSJ: Volume 8, Issue 8, August 2020 ISSN 2320-9186


intensity by est antenna to the radiated field intensity by the reference antenna. Antenna gain, usually expressed in dB, simply refers to the direction of maximum radiation. In this study, the gain of the proposed antenna at the frequency of 3GHz is 3.287dB as shown in Fig.11.

Fig. 13. Polar plot for the elevation angle of the designed antenna

Fig. 11. Gain of the designed antenna at 3GHz
• Directivity: It is desirable to maximize the radiation pattern of the antenna response in a fixed direction in order to transmit or receive power. Likewise, the directivity is dependent only on the shape of the radiation pattern.The achieved directivity of designed antenna is 6.652dBi at 3GHz as shown in fig.12.

Fig. 14. Polar plot of the farfield gain of the designed antenna
every possible impedance in the reflection coefficient of the domain of existence.

Fig. 12. Directivity of the designed antenna
• Smith Chart: Fig.15 shows the smith chart of the proposed antenna. It is the graphical representation of the normalized characteristic impedance. The Smith chart is used as the most useful graphical tools for high frequency circuit applications. The purpose of the Smith chart is to identify

Fig. 15. Smith Chart
IV. CONCLUSION In this paper, a simple rectangular microstrip patch antenna is designed and simulated at 3GHz using CST Microwave

GSJ© 2020

GSJ: Volume 8, Issue 8, August 2020 ISSN 2320-9186



Value Unit

Resonant Frequency (fr) 2.946 GHz


6.652 dBi


3.287 dB

Return Loss

-37.08 dB

Accepted power

0.499 W


1.028 –

Studio software for the application in weather radar, surface ship radar, and some communications satellites [6].The radiation pattern and other significant parameters such as gain, efficiency and loss of return has been studied. The return loss at resonant frequency of 2.946GHz is −30.08 at below −10 db which shows that there is good matching at frequency points.The bandwidth of the proposed antenna at -10dB is found 3.68% and the gain of our designed antenna at the frequency of 3GHz is 3.287dB.
[1] Harish, A.R.; Sachidananda,M.”ANTENNA THEORY AND WAVE PROPAGATION”; ISBN:978-0-19-568666-1
[2] P. Subbulakshmi and R. Rajkumar, “Design and Characterization of Corporate Feed Rectangular Microstrip Patch Array Antenna”, IEEE International Conference on Emerging Trends in Computing Communication and Nanotechnology, 2013.
[3] Md. Tanvir Ishtaique”ul Huque, Md. Kamal Hosain, Md. Shihabul Islam and Md. Al”Amin Chowdhury, “Design and Performance Analysis of Microstrip Array Antennas with Optimum Parameters for X”band Applications,” International Journal of Advanced Computer Science and Applications, Vol. 2, No. 4, 2011
[4] Comparison of Performance Characteristics of Rectangular, Square and Hexagonal Microstrip Patch Antennas; DOI: 10.1109/ICRITO.2014.7014684
[5] International Journal of Engineering Sciences & Emerging Technologies, Feb. 2013. ISSN: 2231 – 6604 Volume 4, Issue 2, pp: 117-126
[6] Design and Simulation of Microstrip Rectangular Patch Antenna for Bluetooth Application, Volume IV, Issue VIII, August 2015, IJLTEMAS ISSN 2278 – 2540.
[7] International Journal of Recent Technology and Engineering (IJRTE) ISSN: 2277-3878, Volume-2, Issue-3, July 2013
[8] Design and Analysis of Microstrip Antenna Array Using CST Software ,1. Karuna Kumari, 2.Prof.P.V.Sridevi Department of ECE GITAM University, Visakhapatnam, A.P., India; DOI 10.4010/2016.1449 ISSN 2321 3361, 2016 IJESC
[9] Rectangular Microstrip Patch Antenna for 2.45 GHz Wireless Applications; Miss Anjali Majale & Mrs.S.R.Mahadik, IJSRD Vol. 3, Issue 08, 2015 — ISSN (online): 2321-0613


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Design and Simulation of High Performance Rectangular