Bandwidth Improvement of Truncated Square Ahaped Patch Antenna

Bandwidth Improvement of Truncated Square Ahaped Patch Antenna

Dhananjay Singp

(Assistant Professor) Mangalmay Institute of technology, Greater Noida, Uttar Pradesh, India

Amit Kumar Mourya2

(Assistant Professor) Mangalmay Institute of technology,

Greater Noida, Uttar Pradesh, India

Karan Singp

(Assistant Professor) Mangalmay Institute of technology,

Greater Noida, Uttar Pradesh, India

Abstract The conventional Rectangular Microstrip patch antenna has very narrow impedance bandwidth, typically of few percent. While Microstrip patch antenna have the advantage of low cost, thin profile, light weight, ease of fabrication, conformable to mounting surface and being integrated in active devices. This paper introduces geometry of corner truncated square shape MPA (Microstrip Patch Antenna) results in increase in Bandwidth from 3.117% to 9.876%. The geometry of slotted and corner truncated square shape MPA is designed on a FR4 substrate with a dielectric constant and tangent loss of 4.4 and 0.035 respectively.

Keywords Bandwidth, Rectangular microstrip patch antenna, Slotted Rectangular microstrip patch antenna, Return Loss, Coaxial probe feed, 2D Radiation pattern.

1. INTRODUCTION

   The conventional Rectangular MPA has very narrow impedance bandwidth, typically of few percent [1]. While Microstrip patch antenna have the advantage of low cost, thin profile, light weight, ease of fabrication, conformable to mounting surface and being integrated in active devices [2]. Also Coaxial probe fed microstrip antennas provide excellent isolation between the feed network and the radiating elements and yield very good front to back ratios [2]. Due to this many advantages the rectangular microstrip patch antennas have many applications like space technology, aircrafts, missiles, tracking, mobile communication, GPS systems, remote sensing and satellite broadcast [3][4]. The most important drawback of microstrip patch antenna is narrow bandwidth. Maximum 8% bandwidths are available with classical microstrip antennas. To overcome this drawback, one of the methods is to cut slots in various shapes. For example, by cutting slits the bandwidth was increased to 2 times [6], by embedding U-slots in stacked patch the bandwidth was improved to 2 times as compared to the conventional Rectangular MPA [2]. And also the wideband characteristics of the antenna is achieved by using the L-shaped probe feeding techniques, the use of series slots (H-shaped) and another pair of parallel slots (E-shaped) lead to the improvement of bandwidth of 22.65%[7]. So, by embedding suitable slots in the radiating patch, compact operation with enhanced impedance bandwidth can be obtained [5].

   In this study, the properties of traditionally Rectangular MPA and Slotted Rectangular MPA with a pin short are presented and compared to each other. The designs were simulated using electromagnetic simulator, Zealand IE3D software. It was found that for the extension of bandwidth, slot can be embedded on the patch

2. ANTENNA DESIGN

   The conventional square patch microstrip antenna is considered the reference antenna to compare the results of that obtained from corner truncation of slotted antenna. The geometry of the conventional square MPA is shown in Figure 1. The patch has the dimension of L×W = (20mm × 20mm) and is printed on FR4 of dielectric constant, = 4.4 and the thickness of the substrate, h = 1.59 mm. A coaxial

   probe is used to connect the microstrip patch at coordinates (0mm, 6mm) and it is made fixed for both the conventional and the modified Rectangular MPA.

   Fig.1. Square MPA of a=20mm

   The geometry of the proposed to extend the bandwidth probe-fed patch antenna with embedding slot is shown in Fig. 2. Impedance bandwidth of about 9.72% can be obtained from the below geometry. The main advantage of this structure is that it produces wider bandwidth than the conventional Square patch.

   Fig.2. Corner truncated and slotted MPA

3. SIMULATED RESULTS

   1. Radiation Pattern: The microstrip antenna radiates normal to its patch surface. So, the elevation pattern for= 0 and = 90 degrees are important for the measurement. The simulated E-plane and H-plane pattern, 2D pattern view the conventional square patch

      and the modified square patch are illustrated in Fig. 3(a) and 3(b).

      Fig.3 (a): 2D Radiation Pattern for square MPA

      Fig.3 (b): 2D Radiation Pattern for corner truncated and slotted square

      MPA

   2. Return Loss and Bandwidth: The Return Loss shown in Fig. 4(a) of the square MPA is -8.90 dB at Resonating frequency at 3.395 GHz.

      Fig.4 (a): Simulated Return Loss for Square MPA

      The Return Loss shown in Fig.4 (b) of the modified square MPA is -29.82dB at Resonating frequency at 3.65GHz and the bandwidth obtained is 9.63%.

      Fig.4 (b): Simulated Return Loss for corner truncated and slotted square MPA

   3. Smith Chart:The loops in the Smith Chart show where the antenna and feed structure were resonant and the nearer the loop to the centre of the chart the better the impedance match. Smith Chart also provides the information about polarization. The Smith chart for the conventional square MPA is given in Fig.5 (a).

      Fig.5 (a): Smith Chart for square MPA

      Fig.5 (b): Smith Chart for Modified Rectangular MPA.

4. CONCLUSION

In this paper, the new geometry proposed the better bandwidth of 9.77% was achieved by truncating corner and digging slots in the antenna design.There is also improvement in return loss. The radiation pattern of the antenna was stable over the entire bandwidth.

REFERENCES

1. H. Wang, X. B. Huang, and D. G. Fang, A Single Layer Wideband U-Slot Microstrip Patch Antenna Array, IEEE Antennas and Wireless Propagation Letters, VOL. 7, 2008.

2. KoraySurmeli, BahattinTuretken, U-Slot Stacked Patch Antenna Using High and Low Dielectric Constant Material Combinations in S-Band, Antenna Test and Research Center (ATAM).

3. Ramesh Garg, PrakashBhartia, Inder Bahl, ApisakIttipiboon, Microstrip Antenna Design Handbook, Artech House Publications, Boston, London.

4. Constantine A. Balanis, Antenna Theory Analysis and Design, Third Edition, Wiley Publication.

5. Kin-Lu Wong, Compact and Broadband Microstrip Antennas, Wiley Publication, 2002.

6. Soliman A. Shetawy, Prof. Esmat A. Abdallah, Prof. Darwish Abdel-Aziz, Slotted Ground Plane of Rectangular Patch Microstrip Antenna with Enhanced Bandwidth and Size Reduction, 12th WSEAS International Conference on Communication,Heraklion, Greece, July 23-25, 2008.

7. Mohammad Taroqul Islam, Mohammad NazmusShakib, Norbahiah Misran, Tiang Sew Sun, Broadband Microstrip Patch Antenna, European Journal of Scientific Research, VOL. 27 No.2 (2009), pp.174-180.