Inset fed inverted U- Slotted Patch Antenna Array for

10GHz Radio-Over-Fiber Applications

Dr. S. Aruna1, S. Manmadha Rao1 and Dr. K. Srinivasa Naik2

1Department of Electronics and Communication Engineering

Andhra University, Visakhapatnam, A.P, India

aruna9490564519@gmail.com 2Vignan’s Institute of Information and Technology, Visakhapatnam, A.P, India

nivas97033205@gmail.com

Abstract. The cumulative need for telecommunications, optical

telecommunications networks in industrialized as well developing the

functionality of radio waves with light waves in a Radio over Fiber network. It

is needed an antenna that provides the process of receivers pick up radio waves

then modulated with light waves. Antennas on Radio over Fiber can work at a

frequency of 10 GHz WPAN (wireless personal area network) communications.

The Wireless frequencies taken by the antenna can then be directly modulated

and distributed through an optical fiber as per the applications. Antenna must

have the characteristics including small size, have an excellent impedance

matching, consumes minute electric current, and has a unidirectional radiation

pattern. In this project, using HFSS the inset fed rectangular microstrip antenna

with Uslot for Radio over Fiber applications in WPAN communications that

can be operated optimally at a frequency of 10 GHz. The simulation results

with optimum performance observed at a frequency of 10 GHz. Results from

the design and realization are patch array rectangular microstrip antenna with

U-slot working at a frequency of 10 GHz with unidirectional radiation pattern;

≥ 3dBi gain; input impedance = 50Ω; and VSWR ≤ 1.

Keywords: WPAN, ROF, U –slot.

1 Introduction

WPAN is a wireless data communication system that allows several data devices can

communicate within a small distance. WPAN has developed a working frequency

region to operate at a frequency of 10 GHz. This project is proposed to follow the

growth of present wireless technology that is implemented antenna that can receive

signals at a frequency of 10 GHz. An antenna that can meet those needs should be

able to consume low power, easy installation, flexible, small size, and low cost [1].

Design of an antenna array method with u-slot can provide a wide bandwidth and a

huge gain. In the previous study, design and implementation of the rectangular patch

microstrip antenna array with inset fed u-slot used in 10 GHz frequency for WPAN

applications.

In this paper is designed and simulated array of inset fed rectangular microstrip

antenna with inverted U-slot, so that comparatively better performance will be

Advanced Science and Technology Letters Vol.147 (SMART DSC-2017), pp.393-398

http://dx.doi.org/10.14257/astl.2017.147.56

ISSN: 2287-1233 ASTL Copyright © 2017 SERSC

accomplished. In this project HFSS simulator is used. FR 4 is used as the substrate

with the following characteristics are relative permittivity (εr) = 4.4, dielectric

thickness (h) = 1.6 mm and conductor thickness= 0.035 mm. From the results - the

rectangular microstrip antenna with U-slot array working at a frequency of 10 GHz

with unidirectional radiation pattern; ≥ 3dBi gain; input impedance = 50Ω; and

VSWR ≤ 1.5. Based on the result, the present proposed device can be implemented

for Radio over Fiber system in WPAN communications that can be used at 10Hz

frequency.

2 Rectangular Patch Antenna

Microstrip Antenna: The microstrip antenna is an antenna that compromises of three

elements, namely, the radiating element (patch), the substrate, and the elements of

earth (ground plane). The patch is placed on top of the substrate, while the ground

plane is placed at the very bottom. The patch has a kind which includes a variety of

shapes like square, a rectangle (rectangular), circles, triangles and annular ring. In this

project rectangular patch with inset-fed is used as in Figure 1[3].

Fig. 1. Simple Patch Antenna Structure

Some main advantages of a microstrip antenna are shape and size is small, light

weight and easy to fabricate with low cost. It is easy to .incorporate with other

Microwave Integrated Circuit, and can be designed with linear and circular

polarization..However, microstrip antenna also has some defects, which are narrow

bandwidth, small gain, and low power efficiency[2,3]. So it is necessary to overcome

the above disadvantages. The U-slot is designed to increase the bandwidth and gain to

achieve the required specification parameters of microstrip antenna dimensions (W

and L)must be known before such as thick dielectric, dielectric constant, width of the

Patch (W) can be calculated by the below equation.

𝑊 =𝐶

2𝑓𝑜√(ℇ𝑟+1)

2

(1)

Where, c is the velocity of light

𝑓𝑜is resonance frequency

ℇ𝑟is relative dielectric constant.

The effective dielectric constant depends on the frequency of operation and is

given by

Advanced Science and Technology Letters Vol.147 (SMART DSC-2017)

394 Copyright © 2017 SERSC

ℇeff =ℇr + 1

2+

ℇr − 1

2[1 + 12

h

W]

−1

2

(2)

Leff = 𝐶

2𝑓𝑜√ℇ𝑒𝑓𝑓

L= Leff − 2ΔL

(3)

Where ΔL=0.412h

The antenna array in this project uses the T-Junction as a series impedance divider

which produce division of impedance in parallel with distributed input impedance

with two output Line channels [4].

3 U-Slotted Rectangular Patch Antenna

Patch with U- Slot Antenna: The slotted microstrip antenna is induced by inductive

coupling provided from supply channel to the slot. The amount of coupling effects

that occur will degrade of the quality factor of the antenna. The degradation in the

quality factor of the antenna cause increase in the bandwidth [8,9].

Fig. 2. HFSS Design of U Slot Antenna

Fig. 3. HFSS Design of U Slot Antenna

Advanced Science and Technology Letters Vol.147 (SMART DSC-2017)

Copyright © 2017 SERSC 395

Table 1. Dimensions of the U-Slot Antenna

4 Results

Advanced Science and Technology Letters Vol.147 (SMART DSC-2017)

396 Copyright © 2017 SERSC

From the obtained results it is identified that the gain ,directivity of the designe

antennas are incresing when compared to the previous one,it is greater than 3dB.The

bandwidth is also increasing ,it is about 500MHz.Return loss is less than -10dB,the

VSWR is less than 2.while designing the antenna care must be taken that the perfect

impedance matching is achieved.

5 Conclusion

By observing the results of designss and simulations it is not much different when

compared to expected.It can be concluded that the antenna parameters such as

VSWR, return loss, bandwidth is in conformity with the specifications required for

Wireless Personal Area Network communication system.The above designed

antennas will be used with the optical modulator for a microwave to lightwave

converter to provide the applications of telecommunication system using radio-over-

fiber(ROF)technology.

Advanced Science and Technology Letters Vol.147 (SMART DSC-2017)

Copyright © 2017 SERSC 397

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398 Copyright © 2017 SERSC