Reconfigurable Microstrip Patch – Slot Antenna ArrayIctte080

INTERNATIONAL JOURNAL FOR TRENDS IN ENGINEERING & TECHNOLOGY VOLUME 5 ISSUE 1 – MAY 2015 - ISSN: 2349 - 9303

Reconfigurable Microstrip Patch – Slot Antenna Array J. Suganya1,

N. Angayarkanni2,

Dr. N. Thangadurai3,

PG Scholar, Department of ECE, PGP College of Engineering and Technology, Namakkal, India1, suganyajeyaprakash@gmail.com

Assistant Professor, Department of ECE, PGP College of Engineering and Technology, Namakkal, India2 angaipgpece@gmail.com

Professor and Head, Department of ECE, PGP College of Engineering and Technology, Namakkal, India3 mrgoldpgpcet@gmail.com

Abstract—In recent years, reconfigurable antennas have received an enormous consideration in the field of wireless communication systems. Antenna parameters such as frequency, radiation pattern, and polarization can be reconfigured. During the past few decades, with the proliferation of wireless communication technologies tremendous improvement has been witnessed in the radio frequency (RF) and microwave antenna design. The modern wireless communication systems are usually deployed with smart antenna or adaptive reconfigurable antenna at the RF front-end. Frequency-reconfiguration in such antennas is needed either for spectrum sensing or ultra wide band communication. Micro-strip patch antennas are considered optimum choice for designing reconfigurable antennas because of their low profile. RF switches such as PIN diodes, varactor diodes, MEMS are commonly used to achieve re-configurability in microstrip patch antennas. The proposed antenna has a microstrip patch above the substrate and a slot at the ground plane. The frequency of operation can be varied by varying the resonating length of the slot. The antenna uses P-I-N diodes for frequency re-configuration. The gain and directivity of frequency reconfigurable antennas can be improved by using arrays of such elements. Such antennas can be used in MIMO LTE and WLAN applications.

Index Terms—Antenna array, microstrip patch antenna, microstrip patch slot antenna, PIN diode. electro mechanical (MEMS) switches or conventional semiconductor switches, as suggested in [3].

The design of a compact, efficient and electronically tunable antenna is presented in [5]. The antenna uses a singlefed resonant slot which is loaded with a series of PIN diode switches. The effective frequency tuning of the antenna is accomplished by varying its effective electrical length. The effective length of the radiator is controlled by the bias voltages of the solid state shunt switches along the slot antenna.

A simple and compact slot antenna with a very wide tuning range is proposed in [6]. An open slot of length equal to oneeighth of the highest frequency of the tuning range is etched at the edge of the ground. To achieve the tunability, only two lumped elements, specifically, a PIN diode and a varactor diode are used. By switching ON and OFF the PIN diode located at the open end of the slot, the slot antenna can resonate as a standard slot (when the switch is on) or a half slot (when the switch is off). The reverse bias of the varactor diode loaded in the slot is varied, providing different capacitances, which in turn provides continuous tuning over a wide frequency range in those two modes.

A frequency-reconfigurable micro-strip patch switchable to slot antenna is proposed in [7]. The antenna switches its frequency at nine different frequency bands between 1.98 and 3.59 GHz. The patch is resonating at 3.59 GHz, whereas the

I. INTRODUCTION

T

HE micro-strip antennas are relatively inexpensive to manufacture and design because of their simple twodimensional physical structure. They have a very low profile, mechanically rugged and can be designed to fit in the vehicle.

They are often mounted on the outside of the aircraft and spacecraft, or incorporated into mobile radio communications devices. They are usually used at UHF and higher frequencies because the size of the antenna is directly dependent on the wavelength at the resonant frequency. Frequency reconfigurable antennas have the facility to reduce the size of front end of the communication system and facilitate prefiltering at the receiver. For frequency tunable antennas [12], much attention has been given to reconfigurable slot antenna designs because of the flexibility of slots to integrate electronic switches for re-configurability. The frequency tuning characteristics of a slot antenna can be achieved by changing the slot effective length or by switching the connection between the feed and the ground. Therefore a frequency reconfigurable antenna is able to support several wireless applications in one single structure [1][2]. The major advantage of reconfigurable antenna is that, such antennas are designed without causing an increase in the total area of the antenna, recommended in [4]. The radiation properties of this reconfigurable antenna can be controlled either by micro

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INTERNATIONAL JOURNAL FOR TRENDS IN ENGINEERING & TECHNOLOGY VOLUME 5 ISSUE 1 – MAY 2015 - ISSN: 2349 - 9303 slot produces eight different operating frequencies between 1.98 and 3.41 GHz. The frequency re-configurability is achieved by using pin diode switches that are placed in the slot in [13]. In [8], a coplanar inverted-F antenna with an electronically controlled ground slot to provide reconfigurability is proposed.

On the other hand, in order to design pattern reconfigurable antennas, the radiating edges, slots or the antenna feeding network should be modified. A novel reconfigurable compact patch array antenna for directional and broadside application is proposed in [9]. The antenna operates at different beam angles. It produces directional beam at 320° or 35° and divisive broadside beam at 43° and 330°. In [10], a dual-band microstrip patch array antenna suitable for both the MIMO 4G Long-Term Evolution (LTE) and the WLAN systems is developed. In this patch array, the gain and directivity of the radiating structure are improved by increasing the number of elements. A similar approach is also proposed in [14]. In order to improve the directional gain and directivity of an antenna structure in MIMO communication systems, array of antenna elements are used

Fig. 2 Geometry of 1×2 array

Fig. 3 Geometry of 1×3 array

II. PROPOSED SYSTEM The frequency reconfiguration can be achieved if the surface current distribution on the antenna is altered. The proposed antenna offers a high degree of flexibility in a reconfigurable antenna. The antenna uses a patch above the substrate and a slot radiator at its ground plane in order to provide multi band frequency of operation. This can be accomplished by varying the resonant length of the slot radiator in the ground plane with the help of PIN diodes.

Fig. 4 Geometry of 1×4 array

structure. The number of antenna elements and their arrangement decides the amount of gain obtained [2].

The simulation of the proposed reconfigurable patch slot antenna is to be done using Keysight’s (formerly Agilent’s) ADS (Advanced Design System) EDA tool. The performance parameters of the antenna which are to be analyzed include reflection co-efficient, Coupling co-efficient, Radiation pattern, Gain and Directivity.

The gain and directivity of the reconfigurable antennas can

III. DESIGN AND CONFIGURATION The design of the single antenna element in the proposed antenna structure is given in Fig. 1. This single antenna element is designed using TACONICRF substrate with permittivity εr of 3.5, loss tangent of 0.0018 and thickness, h of 3.04 mm. The patch above the substrate and the ground plane, below the substrate are constructed using Alumina of thickness 1μm. The dimensions of the patch are 18.3 mm × 29 mm. The ground plane has the dimension of 50 mm × 50 mm.

The dimensions of slot in the ground plane are 36 mm × 2 mm.

To increase the gain and directivity, antenna array is designed. The arrays of 1×2, 1×3 and 1×4 elements are designed as shown in Fig. 2, Fig. 3 and Fig. 4 respectively.

The spacing between the elements in the array is maintained as 3 mm.

Fig. 1 Geometry of the antenna [7]

be improved when they are implemented as antenna array

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INTERNATIONAL JOURNAL FOR TRENDS IN ENGINEERING & TECHNOLOGY VOLUME 5 ISSUE 1 – MAY 2015 - ISSN: 2349 - 9303 The proposed antenna is simulated using the simulation concept adopted in [8], where the conducting PIN diode switch is considered as its equivalent conducting patch along the slot of thickness of 0.2 mm.

0

dB(S(1,3)) dB(S(1,2)) dB(S(1,1))

IV. RESULTS AND DISCUSSIONS The results of reflection co-efficient simulation for the basic frequency reconfigurable antenna structure operating at nine different frequencies depending on the ON and OFF states of the PIN diodes is shown in Fig. 5. The modes of operation of

m1 freq=3.215GHz dB(S(1,1))=-25.721 Valley m2 freq=3.215GHz dB(S(1,2))=-51.498

m1

-20

-40

m2

-60

m3 freq=3.215GHz dB(S(1,3))=-83.858

m3

-80

-100 1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

freq, GHz

Fig. 7 Simulated Reflection Co-efficient of 1×3 antenna array m1 freq=4.760GHz dB(var("f1_emds_a..S"))=-10.498

operation are tabulated in Table I. The reflection co-efficient for antenna arrays of 1×2, 1×3 and 1×4 element arrays are shown in Fig. 6, Fig. 7 and Fig. 8 respectively.

m2 freq=4.722GHz dB(var("f2_emds_a..S"))=-19.429 m3 freq=4.666GHz dB(var("f3_emds_a..S"))=-25.142 m4 freq=4.750GHz dB(var("f4_emds_a..S"))=-22.484

-5 -10

m5 freq=4.479GHz dB(var("f5_emds_a..S"))=-9.464

-15

0

m6 freq=4.403GHz dB(var("f6_emds_a..S"))=-9.638

-20

-25 -30 1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

m1 freq=3.105GHz dB(S(1,1))=-26.779 Valley m2 freq=4.690GHz dB(S(1,1))=-31.509 Valley

m2

-40

m7 freq=4.483GHz dB(var("f7_emds_a..S"))=-6.555 m8 freq=5.000GHz dB(var("f8_emds_a..S"))=-6.081

freq, GHz

m1

-20

dB(S(1,4)) dB(S(1,3)) dB(S(1,2)) dB(S(1,1))

dB(var("f1_emds_a..S")) dB(var("f2_emds_a..S")) dB(var("f3_emds_a..S")) dB(var("f4_emds_a..S")) dB(var("f5_emds_a..S")) dB(var("f6_emds_a..S")) dB(var("f7_emds_a..S")) dB(var("f8_emds_a..S")) dB(var("f9_emds_a..S"))

0

-60 -80 -100

m9 freq=1.641GHz dB(var("f9_emds_a..S"))=-5.099

-120 -140 1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

freq, GHz

Fig. 5 Simulated Reflection Co-efficient of single antenna structure for nine different frequencies

Fig. 8 Simulated Reflection Co-efficient of 1×4 antenna array

TABLE I MODES OF OPERATION OF BASIC ANTENNA STRUCTURE ON Switches

OFF switches

Mode

Frequency (GHz)

S1,S2,S3,S4,S5 S3,S4,S5 S1,S2,S5 S3 S1,S2,S4,S5 S1,S4,S5

S1,S2 S3,S4 S1,S2,S4,S5 S3 S1,S4,S5

M1 M2 M3 M4 M5 M6

4.960 4.772 4.666 4.750 4.479 4.403

S1, S5 S1 -

S2,S3,S4 S2,S3,S4,S5 S1,S2,S3,S4,S5

M7 M8 M9

4.483 5 1.641

The radiation pattern and the values of gain, directivity and radiation intensity for the single element antenna, 1×2, 1×3 and 1×4 element arrays are shown in Fig. 9, Fig. 10, Fig. 11 and Fig. 12 respectively.

0

-10

m1

m1 freq= 3.233GHz dB(S(1,1))=-15.771 Valley m2 freq= 3.233GHz dB(S(1,2))=-50.351

dB(S(1,2)) dB(S(1,1))

-20

-30

-40

m2 -50

-60 1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Fig. 9 Radiation pattern of basic antenna structure

5.0

freq, GHz

Fig. 6 Simulated Reflection Co-efficient of 1×2 antenna array

the basic antenna structure for nine different frequencies of

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INTERNATIONAL JOURNAL FOR TRENDS IN ENGINEERING & TECHNOLOGY VOLUME 5 ISSUE 1 – MAY 2015 - ISSN: 2349 - 9303 V. CONCLUSION The proposed antenna array provides improved gain and directivity. Also this supports the frequency reconfigurability.

The obtained values of gain and directivity are convincing that the proposed antenna is suitable for applications in MIMO LTE and WLAN applications.

REFERENCES [1] D. G. Fang, “Microstrip Patch Antennas,” in Antenna Theory and Microstrip Antennas, Boca Raton, CRC Press, 2010.

[2] Ramesh Garg, “Microstrip patch arrays” in Microstrip Antenna Design Handbook, London:Arctech House, 2001.

[3] Haupt, R. L. and M. Lanagan, “Reconfigurable antennas," IEEE Antennas and Propagation Magazine, Vol. 55, No. 1, 49-61, 2013.

[4] Chang, B. C. C., Y. Qian, and T. Itoh, “A reconfigurable leaky mode/patch antenna controlled by PIN diode switches," IEEE Antennas and Propagation Society International Symposium, Vol. 4, 2694-2697, 1999.

[5] Peroulis, D., K. Sarabandi, and L. P. B. Katehi, “Design of reconfigurable slot antennas," IEEE Transactions on Antennas and Propagation, Vol. 53, No. 2, 645-654, Feb. 2005.

[6] Li, H., J. Xiong, Y. Yu, and S. He, “A simple compact reconfigurable slot antenna with a very wide tuning range,” IEEE Transactions on Antennas and Propagation, Vol. 58, No. 11, 3725-3728, 2010.

[7] Majid, H. A., M. K. A. Rahim, M. R. Hamid, N. A. Murad, and M. F. Ismail, “Frequency reconfigurable micro-strip patch-slot antenna,” IEEE Antennas and Wireless Propagation Letters, Vol. 12, 218-220, 2013.

[8] A. R. Razaliand M. E. Bialkowski, “Reconfigurable coplanar inverted-F antenna with electronically controlled ground slot”, Progress In Electromagnetics Research B, Vol. 34, 63-76, 2011.

[9] M. Jusoh, M. F. Jamlos, M. R. Kamarudin and T. Sabapathy,” A Reconfigurable WiMAX Antenna for Directional and Broadside Application”, International Journal of Antennas and Propagation, Volume 2013, Article ID 405943, 8 pages.

[10] Mohamed Ali Soliman, TahaElsayedTaha, WaelElsayedSwelam, Ali Mohamed Gomaa, “A Wearable DualBand Dielectric Patch Antenna for LTE and WLAN”, Journal of Electromagnetic Analysis and Applications, Vol. 4, page no.

305-309, July 2012.

[11] Huda A. Majid, Mohamad K. A. Rahim, Mohamad R. Hamid, and Muhammad F. Ismail, “Frequency Reconfigurable Microstrip Patch-Slot Antenna with Directional Radiation Pattern”, Progress In Electromagnetics Research, Vol. 144, 319-328, 2014.

[12] Rashid.Y, Ahmad, Amin M, and Marco A. "Compact Planar Multiband Antennas for Mobile Applications", Advancement in Microstrip Antennas with Recent Applications, 2013.

[13] Majid, H. A., M. K. A. Rahim, M. R. Hamid, and M. F. Ismail.

"A Compact Frequency- Reconfigurable Narrowband Microstrip Slot Antenna", IEEE Antennas and Wireless Propagation Letters, 2012.

[14] W. Swelam. "Compact dual-band microstrip patch array antenna for MIMO 4G communication systems", 2010 IEEE Antennas and Propagation Society International Symposium, 07/2010.

[15]

Fig. 10 Radiation pattern of 1×2 array

Fig. 11 Radiation pattern of 1×3 array

Fig. 12 Radiation pattern of 1×4 array

From the above results it is compared that the 1×4 array is TABLE II SIMULATED GAIN AND D IRECTIVITY Antenna

Frequency (GHz)

Directivity (dB)

Gain(dB)

Single antenna

4.777778

4.26945

3.96415

1×2 array 1×3 array 1×4 array

3.66667 3.22222 3.66667

8.97937 9.20831 12.2219

6.6188 8.1988 10.6076

capable of providing high gain and directivity. The comparison of the result is given in Table II.

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