Mode microstrip patch antenna (HMMPA) specifically designed for on-body operation, with the addition of rectangular slots. The structure consists of a square patch of dimension ‘ L ’ with rectangular slots of width ‘ w ’ and length ‘ l ’, etched on a Taconic TLY-3 substrate material of thickness of ‘ h ’. Slot Loaded Square Microstrip Patch Antenna for Dual Band Operation. Faria Jaheen1,., Abdullah Al Noman Ovi. 2, Marjan Akhi. Department of Electrical & Electronics Engineering, American International University-Bangladesh, Dhaka, Bangladesh. Department of Electrical & Electronics Engineering, Faculty of Engineering.

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Novel Design of Microstrip Antenna with Improved Bandwidth

Department of Electronics and Communication, University of Allahabad, Allahabad 211002, India

Received 1 August 2014; Revised 23 September 2014; Accepted 24 September 2014; Published 2 October 2014

Academic Editor: Paolo Colantonio

Copyright © 2014 Km. Kamakshi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A novel design of broadband patch antenna is presented in this paper. The broadband property of the proposed antenna is achieved by choosing a proper selection of dimensions and positions of slot and notch on the radiating patch. The bandwidth of the proposed antenna is found to be 30.5% with operating frequency band from 1.56 GHz to 2.12 GHz. Antenna characteristics are observed for different inclination angles “α” and its effect on bandwidths is also reported. The maximum gain of the antenna is found to be 9.86 dBi and it achieves broadside radiation pattern in the direction of maximum radiation over the operating band. The proposed antenna structure is simulated, fabricated, and tested for obtaining the desired performance. The simulated results are verified with experimental results which are in good agreement.

1. Introduction

In last few years, microstrip patch antenna attracted considerable amount of attention of researchers due to demand of its large variety of applications in different fields such as radar, aircraft, missiles, satellite communications, biomedical telemetry, remote sensing, and different other wireless applications. However, the main limitation of the conventional microstrip patch antenna is narrow bandwidth that restricts its applications [1]. Due to this reason, serious efforts started among the scientists, researchers, and designers to improve the bandwidth of the patch antenna. The bandwidth improvement is achieved by loading a different shape and size of slots and notches on the patch or in the ground plane. There are different other bandwidth enhancement techniques that are also available, but this technique is simple in design and easy in loading and improving bandwidth without increasing the volume of the structures. Therefore, a number of papers have been reported by the researchers for wireless applications such as U-slot loaded rectangular microstrip antenna, L-shaped slot loaded rectangular microstrip antenna, stepped U-slot loaded rectangular microstrip antenna, and half stepped U-slot loaded compact shorted square microstrip antenna, and edge center-shorted square microstrip antenna with stepped slot achieved bandwidth of 17.4%, 14.6%, 14.3%, 23.5%, and 17.3%, respectively [2], compact broadband slotted rectangular microstrip antenna reported 26.7% bandwidth [3], W-shaped patch antenna presented 36.7% bandwidth [4], M-slot folded patch antenna provided 21.17% bandwidth [5], E-H shaped microstrip patch antenna covered frequency range from 1.76 GHz to 2.38 GHz which is equal to 30% bandwidth [6], and V-slots corner notch loaded microstrip patch antenna employed 51% bandwidth [7]. Further, several other radiating structures have been also reported for the bandwidth enhancement of microstrip antenna: star-shaped patch antenna covered frequency range from 4.0 to 8.8 GHz [8]; C-shaped, E-shaped, and U-slot microstrip patch antennas obtained bandwidth of 0.84%, 24%, and 25%, respectively [9], plus-shaped and cross-shaped slot loaded patch antenna achieved bandwidth of 53% and 6.49%, respectively [10, 11]; multi-slotted patch antenna reported 27.62% bandwidth [12]; and slot-coupled multilayer radiating element for synthetic aperture radar application provided bandwidth of 16% bandwidth [13].

This paper is highly motivated from the above reported papers and an antenna radiating structure has been proposed for achieving the improved bandwidth that can be utilized for wireless applications. Most of the reported papers in the literature have achieved gain below 9.0 dBi, whereas the proposed design achieved maximum gain of 9.86 dBi with 30.5% of bandwidth. The performance of proposed antenna is also studied as a function of inclination angle “.” The proposed design is optimized using IE3D simulation software which is based on method of moment. The antenna is simulated, fabricated, and tested for obtaining the desired performance. The simulated results are verified with experimental ones that prove the accuracy of the designed antenna. The details of proposed antenna are given in the following sections.

2. Antenna Configuration and Analysis

The proposed antenna of dimension is fabricated on FR4 substrate with dielectric constant of 4.4. The antenna consist of a rectangular patch loaded with three notches and one slot of dimensions , , , and , respectively. The patch is excited via coaxial feed. The geometry of the patch antenna is shown in Figure 1 and related parameter values are presented in Table 1. The photograph of the fabricated antenna is shown in Figure 2.

The current distribution of the proposed antenna at centre frequency is shown in Figure 3. From Figure 3, it is observed that the maximum current strength is obtained in the upper portion (tilted portion) of the radiating patch which follows longer path in comparison to lower portion. There are four directions of current flowing on the radiating patch which are responsible for the generation of lower and higher order of the TM modes. These nearly excited modes are combined and give wider bandwidth.

3. Results and Discussion

The proposed broadband antenna has been successfully implemented and tested for its desired performance. The simulated results are obtained by method of moment-based simulator, IE3D [14], and its results are experimentally verified by network analyzer. The detailed information about designed antenna characteristics is discussed in this section.

Figure 4 shows the frequency versus reflection coefficient of the proposed antenna. Simulated result of the designed antenna shows four resonating modes at 1.59 GHz, 1.71 GHz, 1.81 GHz, and 1.98 GHz which combine to give broader bandwidth of 29.6%, whereas the experimental results show that the four close resonating modes appear at 1.58 GHz, 1.69 GHz, 1.84 GHz, and 2.01 GHz, respectively, gives wider bandwidth of 30.5%. It is found that the simulated result is in acceptable agreement with the experimental result. Small discrepancy occurred between them due to fabrication losses, whereas simulated results are taken in ideal conditions.

Figure 5 shows the effect of inclination angle or tilt angle “” on the antenna performance. The frequency versus reflection coefficient curve is plotted for different values of inclination angle. With decreasing the values of “” the third resonance disappears and antenna characteristic changes from broadband to dual band. The corresponding bandwidth of the inclination angle also decreases with decreasing the value of tilt angle. Therefore, it is observed that inclination angle plays a crucial role in controlling the resonating frequencies as well as bandwidth of the antenna.

Figure 6 shows the effect of slot lengths “” on the antenna performance while all other parameters are constant. The slot length of the antenna varies from 80 mm to 88 mm and its effects are studied on the antenna characteristics. From Figure 6, it is observed that on increasing the value of slot length resonating frequencies are shifted and their corresponding reflection coefficients are degraded and after the value of slot length “ = 84.0 mm” the second resonance totally disappears and antenna characteristics are changed from broadband to dual band with wider bandwidth.

Figure 7 shows the variation of the reflection coefficient on changing the value of “” (width of the slot). From Figure 7, it is observed that on decreasing the slot width from 8.0 mm to 4.0 mm corresponding bandwidth of the antenna decreases and decreases the value of reflection coefficients. On the other hand, when width of the slot increases from 8.0 mm to 12.0 mm the corresponding bandwidth increases. The slot width of 12.0 mm has not been used for designing because other values of antenna characteristics are degraded.

The simulated gain and measured gain of the proposed antenna at various frequencies are shown in Figure 8. From Figure 8, it is observed that the gain varies from 9.2 dBi to 9.0 dBi over an operating frequency range from 1.56 GHz to 2.12 GHz. The maximum simulated and measured gain are found to be 10.1 dBi (at 1.86 GHz) and 9.86 dBi (at 1.84 GHz), respectively. The total efficiency of the proposed antenna is shown in Figure 9. The maximum simulated and measured efficiency of the antenna are 75.0% and 74.5%, respectively. The small discrepancy is observed between simulated and measured results and this is due to design tolerance of the antenna. These characteristics of an antenna satisfied the requirement of some wireless communication devices.

The E-plane and H-plane radiation pattern at the centre frequency are shown in Figure 10. It is found that the antenna radiates maximum power in broadside direction within the operating band and the 3 dB beamwidth for E-plane is calculated to be 55°, whereas for H-plane it is 45°. It means that, at 1.84 GHz, antenna radiates most of the power at these specified beam widths.

4. Conclusion

A broadband patch antenna with improved bandwidth has been discussed and presented successfully. The designed antenna has a wide impedance bandwidth of 30.5% and creates a maximum radiation in broadside direction with 55° beam width for E-plane and 45° for H-plane. The wide bandwidth is afforded by implementing an inclination at the upper portion of the patch. The effect of inclination angle is also calculated and it is found that at the angle of 30°, antenna characteristics are completely changed from broadband to dual band. The designed antenna also has a maximum gain of 9.86 dBi and shows 74.5% efficiency. Hence, the appropriate position of the discontinuities strongly affects the antenna to achieve the broadband characteristics.

Conflict of Interests

The authors declare that there is no conflict of interests regarding the publication of this paper.

References

1. R. Garg, P. Bhartia, and I. Bahl, Ittipiboon, Microstrip Antenna Design Handbook, Artech House, Norwood, Mass, USA, 2001.
2. A. A. Deshmukh and G. Kumar, “Compact broadband U-slot-loaded rectangular microstrip antennas,” Microwave and Optical Technology Letters, vol. 46, no. 6, pp. 556–559, 2005.View at Publisher · View at Google Scholar · View at Scopus
3. A. A. Deshmukh and K. P. Ray, “Compact broadband slotted rectangular microstrip antenna,” IEEE Antennas and Wireless Propagation Letters, vol. 8, pp. 1410–1413, 2009.View at Publisher · View at Google Scholar · View at Scopus
4. A. A. Lotfi Neyestanak, F. Hojjat Kashani, and K. Barkeshli, “W-shaped enhanced-bandwidth patch antenna for wireless communication,” Wireless Personal Communications, vol. 43, no. 4, pp. 1257–1265, 2007.View at Publisher · View at Google Scholar · View at Scopus
5. F. Jolani, A. M. Dadgarpour, and H. R. Hassani, “Compact M-slot folded patch antenna for WLAN,” Progress in Electromagnetics Research Letters, vol. 3, pp. 35–42, 2008.View at Publisher · View at Google Scholar
6. M. T. Islam, M. N. Shakib, and N. Misran, “Broadband E-H shaped microstrip patch antenna for wireless systems,” Progress in Electromagnetics Research, vol. 98, pp. 163–173, 2009.View at Publisher · View at Google Scholar · View at Scopus
7. M. S. Nishamol, V. P. Sarin, D. Tony, C. K. Aanandan, P. Mohanan, and K. Vasudevan, “A broadband microstrip antenna for IEEE802.11.A/WIMAX/HIPERLAN2 applications,” Progress In Electromagnetics Research Letters, vol. 19, pp. 155–161, 2010.View at Google Scholar · View at Scopus
8. M. Abbaspour and H. R. Hassani, “Wideband star-shaped microstrip patch antenna,” Progress in Electromagnetics Research Letters, vol. 1, pp. 61–68, 2008.View at Google Scholar
9. S. Bhardwaj and Y. Rahmat-Samii, “A comparative study of c-shaped, e-shaped, and u-slotted patch antennas,” Microwave and Optical Technology Letters, vol. 54, no. 7, pp. 1746–1757, 2012.View at Publisher · View at Google Scholar · View at Scopus
10. X. L. Bao and M. J. Ammann, “Small patch/slot antenna with 53 input impedance bandwidth,” Electronics Letters, vol. 43, no. 3, pp. 146–148, 2007.View at Publisher · View at Google Scholar · View at Scopus
11. M. Albooyeh, N. Komjani, and M. Shobeyri, “A novel cross-slot geometry to improve impedance bandwidth of microstrip antennas,” Progress in Electromagnetics Research Letters, vol. 4, pp. 63–72, 2008.View at Publisher · View at Google Scholar
12. M. T. Islam, M. N. Shakib, and N. Misran, “Multi-slotted microstrip patch antenna for wireless communication,” Progress In Electromagnetics Research Letters, vol. 10, pp. 11–18, 2009.View at Publisher · View at Google Scholar · View at Scopus
13. P. Capece, L. Lucci, G. Pelosi, M. Porfilio, M. Righini, and W. Steffè, “A multilayer PCB dual-polarized radiating element for future SAR applications,” IEEE Antennas and Wireless Propagation Letters, vol. 13, pp. 297–300, 2014.View at Publisher · View at Google Scholar · View at Scopus
14. Zeland Software, IE3D Simulation Software, Version 14.05, Zeland Software, Fremont, Calif, USA, 2008.

Faria Jaheen ¹, Abdullah Al Noman Ovi ², Marjan Akhi ³

¹Department of Electrical & Electronics Engineering, American International University-Bangladesh, Dhaka, Bangladesh

²Department of Electrical & Electronics Engineering, Faculty of Engineering, Purdue University, West Lafayette, United States

³Department of Electrical & Electronics Engineering, Faculty of Engineering, Ahsanullah University of Science and Technology, Dhaka, Bangladesh

Correspondence to: Faria Jaheen , Department of Electrical & Electronics Engineering, American International University-Bangladesh, Dhaka, Bangladesh.

Email:

Copyright © 2016 Scientific & Academic Publishing. All Rights Reserved.

This work is licensed under the Creative Commons Attribution International License (CC BY).
http://creativecommons.org/licenses/by/4.0/

Abstract

In this paper, a design to obtain dual band performance in square microstrip patch antenna has been proposed. This high directive probe feed antenna has only 30 mm 30 mm patch. It provides dual-band operation by means of three narrow slots close and parallel to the patch radiating edges. It shows quiet analogous and satisfactory radiation pattern at both frequencies in the face of using a relatively facile feeding technique named co-axial feeding. The directivity of proposed antenna is above 6.5 dB at both bands. The dual band results and their radiation performances are observed using ‘CST Microwave Studio’ based realistic simulations. In short, realistic numerical simulation of a novel design is presented in this paper, considering losses and the presence of the antenna feed, showing how a practical realization is foreseeable.

Keywords: Microstrip antenna, Dual-band, Radiation pattern

Cite this paper: Faria Jaheen , Abdullah Al Noman Ovi , Marjan Akhi , Slot Loaded Square Microstrip Patch Antenna for Dual Band Operation, Electrical and Electronic Engineering, Vol. 6 No. 1, 2016, pp. 11-17. doi: 10.5923/j.eee.20160601.03.

1. Introduction

The dual-frequency microstrip patch antennas are widely used to meet the need of frequency reuse often required in wireless communication, satellite systems, radar, Synthetic Aperture Radar (SAR), Global Position System (GPS) applications. Microstrip patch antennas are also extensively employed in many practical applications due to inherent advantages of low-profile, light weight, simple planar structures, conformability, ease of fabrication and integration with RF devices [1-7]. Though multi-frequency operations can be obtained by using wide band antennas and suitable electronic circuits, this solution has several drawbacks in terms of efficiency and noise performances [8]. Whereas dual-frequency microstrip patch antennas maintain good noise temperature and efficiency. A perfect dual-band antenna always shows identical radiation properties at its both operating frequencies. Dual-band can be attained by using multilayer structures [9], [10], parasitic elements coupled to the main patch [11], aperture coupled parallel resonators [12], log-periodic or quasi-log-periodic structures [13], [14]. But these structures have some limitations such that overall large size, difficulties in designing and manufacturing. Likewise, stagger-tuned resonators [15],reactively loaded patches with short pins [16], varactor diodes [17] or optically controlled pin diodes [18] have been successfully developed for increasing bandwidth and dual band operation. However the patch size is small for high frequencies and it becomes difficult to put up the diodes or pins underside it. In order to tune resonant frequency an adjustable air gap between substrate and ground plane has also been carried out [19]. Two complications emerge according to this idea; initially the width of air gap has to be changed mechanically and subsequently, an array consisting of large number of element is difficult to design. These are just some of the attempts already made to accomplish multi-frequency action of patch antennas. Nevertheless in the Antenna Design literature, dual-band microstrip patch antennas are categorized into two types depending upon the number of radiating elements, explicitly, multi-resonator antennas and reactive loading antennas. In multi-resonator antennas double resonant behavior is achieved via multiple radiating elements each supporting strong currents and radiation at its resonance. Aperture-coupled parallel microstrip dipoles [12] as well as the multi-layer stacked-patch antennas using circular [20], annular [21], rectangular [22], and triangular [23] patches are included in this category. The drawbacks of multi-resonator antennas are large size and high cost. In hand-held terminals they face trouble to be installed owing to their large size. They are costly due to multiple substrate layers in their structure. The reactive-loading microstrip patch antenna consisting of a single radiating element obtain dual frequency action by connecting coaxial [24] or microstrip stubs [25] at the radiating edges of a rectangular patch. Frequency Ratio (FR) below 1.2 is the negative aspect of this solution. Although higher values of frequency ratio (around 4 to 5) can be gained by means of two lumped capacitors connected from the patch to the ground plane [26]. In reactive loading antennas dual-band operation can be realized through multiple shorting pins located symmetrically with respect to the patch axes [27] as well. An additional kind of reactive loading can be introduced by etching slots on a patch. The slot loading on patch permits to robustly modify the resonant mode of a rectangular patch, particularly when the slots cut the current lines of the unperturbed mode. Previously, mode modification in rectangular microstrip patch antenna was performed by using symmetrical rectangular slots closed to radiating edges [28-31], J slot [32] etc. Symmetrical slot loading in elliptical patch antenna also lead to the same result [32]. Symmetrical slots were introduced in those designs to lower the resonant frequency of TM₀₃₀ mode to act like TM₀₁₀ mode and thus dual band antennas were successfully modeled. The simultaneous use of slots and short-circuit vias, allows to obtain an FR from 1.3to 3depending on the number of vias as shown in [32].In this paper, we have proposed a design to obtain dual band performance via mode modification in square microstrip patch antenna with dimension 30 mm 30 mm. With the help of slots near the radiating edges of the patch, the typical microstrip patch antenna can be twisted for multi-frequency operation. The proposed antenna provides dual-frequency operation by dint of three rectangular slots close and parallel to the patch radiating edges. The slots near radiating edges split the field into two orthogonal modes. At both bands the antenna shows analogous and satisfactory radiation performance. Furthermore, high directivity is a key prerequisite for modern satellite based communication system. The directivities of the antenna are above 6.5 dB at both bands (quiet satisfactory). Thus the antenna can be used in various applications such as SAR, GPS, WLAN, Wi-Fi, WiMAX and various other applications. In section 2 the design procedures of proposed antenna are discussed. In section 3 and 4 simulation results are conversed for projected design.

2. Antenna Design

To analyze proposed microstrip antenna, several methods and software are available. We employed ‘CST Microwave Studio’ based realistic simulations to analyze microstrip antenna. The combination of the proprietary PERFECT BOUNDARY APPROXIMATION (PBA) with the unbeatable efficiency of the Finite Integration Technique (FIT) is the basis for CST MICROWAVE STUDIO. This software uses modules based on methods including FEM, MoM, MLFMM and SBR to calculate desired parameters such as s parameter, input impedance, and radiation pattern and so on. Figure 1 shows the basic design of our proposed single-fed (probe fed) microstrip antenna. The square patch has equal side length L = 30 mm. Permittivity of the substrate is 2. The thickness of the substrate is t = 1.5 mm. The dimension of each rectangular symmetrical slot is 28 mm 1 mm. Other dimensions are given in Figure 1.

Figure 1. Geometry of proposed slot-loaded square microstrip patch antenna. Detailed information and constitutive parameters are: Lg = 40 mm, Wg = 40 mm, Ls = 28 mm, Ws = 1 mm, d12 = 24 mm, d13 = 26 mm, d23 = 1 mm, d = 1 mm, l = 1 mm, h = 1.5 mm, = 2 and feed position fp: (x, y) = (0, - 7.5 mm) considering origin at the centre of the patch

If we use substrate having permittivity 2 (with thickness = 1.5 mm) and dimension is only 30 mm × 30 mm (with no slot), then the normal resonance frequency is around 3.475 GHz. That means the antenna operates only at single frequency. To get dual band operation, three symmetrical ‘l’ slot(Figure 1) with dimension L_S and W_s are etched on the square patch adjacent and parallel to the radiating edges of the antenna. The slots are numbered resembling slot 1, slot 2 and slot 3 as shown in figure 1. The location of the slot 1 and slot 3 with respect to the patch is defined by the dimensions dand l. the distance between slot 1& slot 2, slot 2 & slot 3 and slot 1 & slot 3 are denoted by d₁₂, d₂₃ and d₁₃ respectively. The thickness of substrate is symbolized by h and the position of probe feed is at f_p. L_g and W_g represents the length and width of ground plane.Figure 2 shows S-parameter performance of the proposed square microstrip patch antenna. It demonstrates the designed antenna return loss in 3.754 and 4.861 GHZ are -26.087872 dB and -10.301681 dB in that order. In Figure 3 and Figure 4 three dimensional radiation pattern and polar plot of TM₀₁₀ mode at 3.754 GHz are presented respectively. In Figure 5 and Figure 6 three dimensional radiation patterns and polar plot of TM_0δ0 mode at 4.861 GHz are illustrated correspondingly. Other antenna parameters are given below in Table.

Figure 2. S-parameter performance of the proposed square microstrip patch antenna, TM010 mode at 3.754 GHz and TM0δ0 mode at 4.861 GHz

Figure 3. Three dimensional radiation pattern of TM010 mode at 3.754 GHz

Figure 4. Polar plot of TM010 mode at 3.754 GHz

Figure 5. Three dimensional radiation pattern of TM0δ0 mode at 4.861 GHz

Microstrip Patch Antenna Pdf

Figure 6. Polar plot of TM0δ0 mode at 4.861 GHz

Table 1. Antenna Parameters

3. Theoretical Analysis of Loading Slots on the Patch

The frequency of operation of the patch antenna is determined by the length L. The center frequency will be approximately given by [34],

Analysis Of Slot Loaded Microstrip Patch Antenna

(1)

As the length of proposed antenna, and the permittivity of the substrate, and of light so the center frequency of the proposed antenna can be calculated as follows:Owing to loading three parallel slots in the proposed antenna it operates at two separate frequencies at 3.754 GHz and 4.861 GHz. The effect of slot on the patch can be analyzed using the duality relationship between the dipole and the slot. The Babinet’s principle [33] of optics is used to derive the property that the radiation pattern of a slot antenna resembles that of a complimentary metallic strip dipole. Babinet’s principle states that (in optics) that when a field behind a screen with an opening is added to the field of a complementary structure (that is a shape covering the screen hole), then the sum is equal to the field where there is no screen. In the proposed antenna the patch is fed by co-axial cable. Since the slot is thin, the voltage can be sinusoidal with zero voltage across the ends of slot. In this case the voltage across the slot is given as [35]

(2)

The current distribution of long dipole given as follows [35]

(3)

The total electric field at the far-field point from the antenna is given by [35]

(4)

Performing integration yields

(5)

The Poynting vector can be written as [36]

(6)

Therefore, the total power radiated from the dipole antenna is given by [36]

(7)

If the radiation resistance is defined in terms of maximum current then it may be given as [36]

(8)

Solution of equation (8) yields

(9)

And The input impedance of the dipole or slot is given by [35]

(10)

Where the electric field along the z-direction.

4. Antenna Feed

The structure is fed by coaxial probes. The reason behind using this feeding technique is that is the feed can be placed at any desired location inside the patch in order to match with its input impedance (i.e. 50 Ω). Besides, coaxial probe provides low spurious radiation. As seen from Figure 1, the inner conductor of the coaxial connector extends through the dielectric and is soldered to the radiating patch, while the outer conductor is connected to the ground plane. The radius of the inner conductor is 0.3 mm and the radius of outer conductor is 1.2 mm.Selection of the suitable feed location is a dilemma for dual band operation. Because the radiation pattern regularity is influenced by the symmetry of the feeds. A better procedure (when slot case) can be found for probe feed location using modal matching technique following [30]. But in case of our proposed design, the ‘l’ slot will make all these procedures much complex and obviously time consuming. Therefore simulation based iterative process is used by segmenting proposed antenna to choose the suitable feed location. Thus the feed is located at f_p: (x, y) = (0, - 7.5 mm) considering origin at the centre of the patch.

5. Dual Band & Frequency Shifting Operation

The resonant behavior of the slot loaded patch antenna can be explained by initiating from the cavity model description of an unslotted rectangular patch and from cavity perturbation theory. According to cavity model, the first three modes that can be excited in the cavity are usually denoted by TM₀₁₀, TM₀₂₀ and TM

Slot Loaded Compact Microstrip Patch Antenna For Dual Band Operation

₀₃₀. These modes correspond to longitudinal currents distributed on the patch which have nulls at the radiating edges. The TM₀₁₀ is the most used in practical applications since the TM₀₂₀ mode has a broadside-null radiation pattern and the TM₀₃₀ produces grating lobes. While three slots loaded in proposed antenna then the resonant behavior is discussed by cavity perturbation theory. In proportion to cavity perturbation theory, when a resonant cavity is perturbed, i.e. when a foreign object with distinct material properties is introduced into the cavity or when a general shape of the cavity is changed, electromagnetic fields inside the cavity change consequently. The underlying assumption of cavity perturbation theory is that electromagnetic fields inside the cavity after the change differ by a very small amount from the fields before the change. But the change in cavity causes significant change in resonant frequency. The corresponding change in resonant frequency can be approximated as (11) [37]:

(11)

Here is the resonant frequency of the original cavity and is the resonant frequency of the perturbed cavity, represent the magnetic and electric field of the original cavity correspondingly, are original permeability and permittivity respectively.Equation (11) can be written in terms of stored energy as follows [37]:

(12)

Here are the changes in the stored magnetic energy and electric energy respectively, after perturbation and is the total stored energy in the cavity.Due to etching three narrow slots near radiating edges of proposed antenna, the currents of TM₀₃₀ resonant frequency circulate around the slots and become similar to the TM₀₁₀ mode. Thus the slots also modify three lobe shape of TM₀₃₀ mode to regular behavior. But they do not perturb TM₀₁₀ mode significantly. The amount of perturbation on excited mode in loaded slot antenna does not have close form formula to calculate, but there is a relationship between two perturbed frequencies (TM₀₁₀ and TM

Applications Of Microstrip Patch Antenna

₀₃₀) as given in equation (13) [28].

(13)

In addition the slots cause minor perturbations of TM₀₁₀

Microstrip Antenna Hfss

are expected because the slots are located close to the current minima. The radiating mechanism associated with this first mode is essentially the same as that of a patch without slots. As a consequence, its resonant frequency is only slightly different from that of a standard (unslotted) patch. The resonant frequency of unslotted antenna is 3.475 GHz whereas the resonant frequency of slot-loaded antenna for first mode (i.e. TM₀₁₀ mode) is 3.754 GHz. In loaded slot microstrip antenna, the second mode (TM₀₂₀) has also good radiation properties. But because of its null effect in broadside direction, it cannot be used as broadside radiator.

6. Conclusions

A design of dual band single feed microstrip patch antenna has been proposed and described. The new geometry of the patch has verified to be a high directive and dual band element. This is particularly important for radar systems where directional characteristics, narrow bandwidth are often demanded to determine the range, altitude, direction, or speed of objects. It can also be applied to satellite systems where two channels are needed to provide communication links between various points on Earth. Here, antenna size (30 mm × 30 mm) is reduced compared to the conventional dual-band antenna design. The results show satisfactory radiation pattern, gain & directivity in both frequencies. As a result the proposed antenna is attractive for radar and satellite systems.

Microstrip Patch Antenna Calculator

References

Slot Loaded Microstrip Patch Antenna Calculator

[1]	James, J.R., and Hall, P.S. (Eds.) (1989). Handbook of Microstrip Antennas, Peter Peregrinus, London.
[2]	Chang, K. (Ed.) (1989). Handbook of Microwave and Optical Components, 1, John WileyandSons, New York, NY.
[3]	Bhartia, P., Rao, K.V.S., and Tomar, R.S. (1991). Millimeter-wave Microstrip and Printed Circuit Antennas. Artech House, Norwood, MA.
[4]	Pozar, D.M., and Schaubert, D.H. (Eds.) (1995). Microstrip Antennas: The Analysis and Design of Microstrip Antennas and Arrays, IEEE Press, New York, NY, USA.
[5]	Gao, S.C., and Zhong, S.S. (1999). Analysis and design of dual-polarized microstrip antenna array. International Journal of RF and Microwave Computer-Aided Engineering, 9(1), 42–48.
[6]	Gao, S.C., and Zhong, S.S. (1998). Dual-polarized microstrip antenna array with high isolation fed by coplanar network. Microwave and Optical Technology Letters, 19(3), 214–216.
[7]	Gao, S.C. (1999). Dual-polarized microstrip antenna elements and arrays for active integration. Ph.D. thesis, Shanghai University Press, Shanghai, P. R. China.
[8]	Avitabile, G., Maci, S., Bonifacio, F., and Salvador, C. (1994). Dual band circularly polarized patch antenna. Antennas and Propagation Society International Symposium, 1994. AP-S. Digest, 1, 290-293.
[9]	Hall, P.S., Wood, C., and Garrett, C. (1979). Wide bandwidth microstrip antennas for circuit integration. Electronics Letters, 15(15), 458–460.
[10]	Schaubert, D.H., andFarrar, F.G. (1979). Some conformal printed circuit antenna designs. Proceedings of Workshop on Printed Circuit Antenna Technology, New Mexico State University, Las Cruces, 5/1-21.
[11]	Kumar, G., and Gupta, K.C. (1984). Broad-band microstrip antennas using additional resonators gap-coupled to the radiating edges. IEEE Transactions on Antennas and Propagation, 32(12), 1375–1379.
[12]	Croq, F., and Pozar, D.M. (1992). Multifrequency operation of microstrip antennas using aperture-coupled parallel resonators. IEEE Transactions on Antennas and Propagation, 40(11), 1367–1374.
[13]	Hall, P.S. (1980). New wideband microstrip antenna using log-periodic technique. Electronics Letters, 16(4), 127-128.
[14]	Pues, H., Bogaers, J., Pieck, R., and van de Capelle, A. (1981). Wideband quasi-log-periodic microstrip antenna. IEE Proceedings Part H, Microwaves, Antennas and Propagation, 128(3), 159-163.
[15]	Pues, H., Vandensande, J., van de Capelle, A., and Leuven, K. (1978). Broadband microstrip resonator antennas. Antennas and Propagation Society International Symposium, 16, 268-272.
[16]	Schaubert, D.H., Farrar, F.G., Sindoris, A., and Hayes, S.T. (1981). Microstrip antennas with frequency agility and polarization diversity. IEEE Transactions on Antennas and Propagation, 29(1), 118–123.
[17]	Richards, W.F., Lo, Y.T., and Harrison, D.D. (1981). An improved theory for microstrip antennas and applications. IEEE Transactions on Antennas and Propagation, 29(1), 38–46.
[18]	Daryoush, A., Bontzos, K., and Herczfeld, P. (1986). Optically tuned patch antenna for phased array applications. Antennas and Propagation Society International Symposium, 24, 361–364.
[19]	Dahele, J.S., and Lee, K.F. (1985). Theory and experiment on microstrip antennas with airgaps. IEE Proceedings Part H, Microwaves, Antennas and Propagation, 132(7), 455-460.
[20]	Long, S.A., and Walton, M. (1979). A dual-frequency stacked circular-disc antenna. IEEE Transactions on Antennas and Propagation, 27(2), 270–273.
[21]	Dahele, J.S., Lee, K.F., and Wong, D.P. (1987). Dual-frequency stacked annular-ring microstrip antenna. IEEE Transactions on Antennas and Propagation, 35(11), 1281–1285.
[22]	Wang, J., Fralich, R., Wu, C., and Litva, J. (1990). Multifunctional aperture coupled stack patch antenna. Electronics Letters, 26(25), 2067-2068.
[23]	Mirshekar-Syahkal, D., and Hassani, H.R. (1993). Characteristics of stacked rectangular and triangular patch antennas for dual band application. Antennas and Propagation, 1993., Eighth International Conference on, 2, 728-731.
[24]	Richards, W.F., Davidson, S.E., and Long, S.A. (1985). Dual-band reactively loaded microstrip antenna. IEEE Transactions on Antennas and Propagation, 33(5), 556–561.
[25]	Davidson, S.E., Long, S.A., and Richards, W.F. (1985). Dual-band microstrip antennas with monolithic reactive loading. Electronics Letters, 21(20), 936-937.
[26]	Waterhouse, R.B., and Shuley, N.V. (1992). Dual frequency microstrip rectangular patches. Electronics Letters, 28(7), 606-607.
[27]	Zhong, S.S., and Lo, Y.T. (1983). Single-element rectangular microstrip antenna for dual-frequency operation. Electronics Letters, 19(8), 298-300.
[28]	Maci, S. Biffi Gentili, G., Piazzesi, P., and Salvador, C. (1995). Dual-band slot-loaded patch antenna. IEE Proceedings - Microwaves, Antennas and Propagation, 142(3), 225-232.
[29]	Mahdy, M.R.C., Zuboraj, M.R.A., Ovi, A.A.N., and Matin, M.A. (2011). NOVEL DESIGN OF TRIPLE BAND RECTANGULAR PATCH ANTENNA LOADED WITH METAMATERIAL. Progress in Electromagnetics Research Letters, 21, 99–107.
[30]	Ovi, A.A.N., Chowdhury, M.R., Zuboraj, M.R.A., and Matin, M.A. (2013). Design of Miniaturized Dual Band Microstrip Antenna Loaded With Asymmetric J Slot. Journal of Electrical Engineering and Electronic Technology, 2(1).
[31]	Ovi, A.A.N., Saha, N., Dey, S., and Alam, N.N. (2012). Symmetrical Slot Loaded Dual Band Elliptical Microstrip Patch Antenna. Progress in Electromagnetics Research Symposium (PIERS) 2012, 538-541.
[32]	Wang, B.F., and Lo, Y.T. (1984). Microstrip antennas for dual-frequency operation. IEEE Transactions on Antennas and Propagation, 32(9), 938–943.
[33]	F.A. Jenkins and H.A. White (1957). Fundamentals of Optics, McGraw-Hill Book Company New York.
[34]	Constantine A. Balanis (2nd Ed.). Antenna Theory.819.
[35]	Wolff Edward A (1988) Antenna Analysis (Massachusetts: Artech house), 148 -150 and 37-48.
[36]	Shivnarayan Shashank Sharma and Babau R Vishvakarma (2005). Analysis of slot-loaded rectangular microstrip patch antenna. Indian Journal of Radio and Space Physics, 34, 424-430.
[37]	Pozar, D.M. (1998). Microwave Engineering, 2nd edition,JohnWiley and Sons, New York, NY.