A Dual-Band Notched Ultra Wideband Microstrip Antenna · Web view2019. 7. 21. · The antenna...

A Dual-Band Notched Ultra Wideband Microstrip Antenna

CHAPTER-1

INTRODUCTION

1.1. Antenna

The antenna design for high-speed multimedia connectivity represents a challenging activity

for designers of fixed and mobile wireless communication systems. In fact, the rapid growth of

mobile systems toward the fifth-generation (5G systems) requires multiband, wideband, and

UWB antennas suitable to cover mobile and wireless services and to reduce the system

complexity, the overall device dimensions, and costs. Many efforts are underway to identify new

antenna geometries suitable to satisfy the challenging requirements of the modern wireless

communication systems.

Fig 1.1 Antenna

Nowadays there is more demand for wide bandwidth antenna, because it covers more

operating frequencies. This has been realized in Microstrip antenna or coplanar waveguide

(CPW)-fed antenna. The advantage of CPW and microstrip antenna is that it is fully compact,

small in size, length, lightweight and easy to fabricate. CPW has received more attention due to

its compact size, high radiation efficiency, and compatibility with other circuits. Mechanism of

microstrip antenna is metal printed on one side of substrate for ground and other side print for

radiation patch on substrate. But in CPW, radiation patch and ground should be in same plane

and thus it is known as coplanar waveguide.

Vardhaman College of Engineering Department of ECE Page 1


An antenna is a device to transmit and/or receive electromagnetic waves. Electromagnetic waves

are often referred to as radio waves. Most antennas are resonant devices, which operate

efficiently over a relatively narrow frequency band. An antenna must be tuned (matched) to the

same frequency band as the radio system to which it is connected, otherwise reception and/or

transmission will be impaired.

1.2. Fundamentals of antenna:

• Field intensity for various directions (antenna pattern).

• Total power radiated when antenna is excited by a current or voltage of known intensity.

• Radiation efficiency which is the ratio of power radiated to the total power.

• The input impedance of antenna for maximum power transfer.

• The bandwidth of the antenna or range of frequencies over which the above properties are

nearly constant.

Multiband antennas:

A multiband antenna is an antenna designed to operate on several bands. These antennas often

use designs where one part of the antenna is active for one band, and another part is active for a

different band. A multiband antenna may have lower than average gain or may be physically

larger in compensation. The need for mankind to communicate and exchange information with

each other fuels the development of various communication methods and systems, each system

differs in the operation.



Antenna Parameters:

Gain:

Antenna gain is usually defined as ratio of the power produced by the antenna from a far field

source on the antenna beam axis to the power produced by a hypothetical lossless isotropic

antenna, which is equally sensitive to signals from all directions.

G=Eantenna.D

In electromagnetics, an antenna's power gain or simply gain is a key performance number which

combines the antenna's directivity and electrical efficiency. In a transmitting antenna, the gain

describes how well the antenna converts input power into radio waves headed in a specified

direction. In a receiving antenna, the gain describes how well the antenna converts radio waves

arriving from a specified direction into electrical power. When no direction is specified, "gain" is

understood to refer to the peak value of the gain, the gain in the direction of the antenna's main

lobe. A plot of the gain as a function of direction is called the radiation pattern.

Directivity:

In electromagnetic, directivity is a parameter of an antenna or optical system which measures

the degree to which the radiation emitted is concentrated in a single direction. It measures

the power density the antenna radiates in the direction of its strongest emission, versus the power

density radiated by an ideal isotropic radiator (which emits uniformly in all directions) radiating

the same total power. Directivity is an important measure because many antennas and optical

systems are designed to radiate electromagnetic waves in a single direction or over a narrow

angle. Directivity is also defined for an antenna receiving electromagnetic waves, and its

directivity when receiving is equal to its directivity when transmitting.

Effective aperture:

The effective antenna aperture is a theoretical value which is a measure of how effective an

antenna is at receiving power. The effective aperture /area can be calculated by knowing the gain

of the receiving antenna.


https://en.wikipedia.org/wiki/Isotropic_radiator

https://en.wikipedia.org/wiki/Power_density

https://en.wikipedia.org/wiki/Optical_system

https://en.wikipedia.org/wiki/Antenna_(radio)

https://en.wikipedia.org/wiki/Electromagnetism

https://en.wikipedia.org/wiki/Radiation_pattern

https://en.wikipedia.org/wiki/Main_lobe

https://en.wikipedia.org/wiki/Main_lobe

https://en.wikipedia.org/wiki/Radio_wave

https://en.wikipedia.org/wiki/Antenna_efficiency

https://en.wikipedia.org/wiki/Directivity


https://en.wikipedia.org/wiki/Electromagnetics


Efficiency:

In antenna theory, antenna efficiency is most often used to mean radiation efficiency. In the

context of antennas, one often just speaks of "efficiency." It is a measure of the electrical

efficiency with which a radio antenna converts the radio-frequency power accepted at its

terminals into radiated power. Likewise, in a receiving antenna it describes the proportion of the

radio wave's power intercepted by the antenna which is actually delivered as an electrical signal.

It is not to be confused with aperture efficiency which applies to aperture antennas such as

the parabolic reflector. The antenna efficiency is a ratio of the power delivered to the antenna

relative to the power radiated from antenna. A high efficiency antenna has most of the power

present at the antennas input radiated away. Antenna efficiency is a number between 0 and 1.

VSWR:

The Voltage Standing Wave Ratio (VSWR) is an indication of the amount of mismatch

between an antenna and the feed line connecting to it. The range of values for VSWR is from 1

to ∞. A VSWR value under 2 is considered suitable for most antenna applications. The antenna

can be described as having a good match. So when someone says that the antenna is poorly

matched, very often it means that the VSWR value exceeds 2 for a frequency of interest.

1.3. Types of antenna:

• Aperture antennas.

• Reflector antennas.

• Dipole antennas.

• Loop antennas.

• Array antennas.


https://en.wikipedia.org/wiki/Parabolic_reflector

https://en.wikipedia.org/wiki/Aperture_efficiency_(antennas)

https://en.wikipedia.org/wiki/Electrical_efficiency

https://en.wikipedia.org/wiki/Electrical_efficiency



Dipole Antenna:

Fig 1.2 Dipole antenna

A dipole antenna is one of the most straightforward antenna alignments. This dipole antenna

consists of two thin metal rods with a sinusoidal voltage difference between them. The length of

the rods is chosen in such a way that they have quarter length of the wavelength at operational

frequencies. These antennas are used in designing their own antennas or other antennas. They are

very simple to construct and use.

Array antennas:

Fig 1.3 Array antenna

A grouping of similar or different antennas forms an array antenna. The control of phase shift

from element to element is used to scan electronically the direction of radiation.

Loop antennas:

Fig 1.4 Loop antenna



A loop of wire, with many turns, is used to radiate or receive electromagnetic energy. A loop

antenna is a type of a radio antenna, which consists of a loop (circular electrical conductor) with

ends connected to the transmission line.

Reflector antenna:

Fig 1.5 Reflector antenna

An antenna reflector is a device that reflects electromagnetic waves. Antenna reflectors can exist

as a standalone device for redirecting radio frequency (RF) energy, or can be integrated as part of

antenna assembly.

Type of Reflector antenna

A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the

cross-sectional shape of a parabola, to direct the radio waves. The most common form is shaped

like a dish and is popularly called a dish antenna or parabolic dish. ... They are also used in radio

telescopes.

A corner reflector antenna is a type of directional antenna used at VHF and UHF frequencies.

It was invented by John D. Kraus in 1938. It consists of a dipole driven element mounted in front

of two flat rectangular reflecting screens joined at an angle, usually 90°.

Aperture antenna:

An Antenna with an aperture at the end can be termed as an Aperture antenna. Waveguide is an

example of aperture antenna. The edge of a transmission line when terminated with an opening



radiates energy. This opening which is an aperture makes it an Aperture antenna.

Fig 1.6 Aperture antenna

1.4. Technical approach

Microstrip antenna is an antenna fabricated using microstrip techniques on a printed circuit

board (PCB). They are mostly used at microwave frequencies. An individual microstrip antenna

consists of a patch of metal foil of various shapes (a patch antenna) on the surface of a PCB

(printed circuit board), with a metal foil ground plane on the other side of the board. Most

microstrip antennas consist of multiple patches in a two-dimensional array. The antenna is

usually connected tos the transmitter or receiver through foil microstrip transmission lines.

The radio frequency current is applied (or in receiving antennas the received signal is produced)

between the antenna and ground plane. Microstrip antennas have become very popular in recent

decades due to their thin planar profile which can be incorporated into the surfaces of consumer

products, aircraft and missiles; their ease of fabrication using printed circuit techniques; the ease

of integrating the antenna on the same board with the rest of the circuit, and the possibility of

adding active devices such as microwave integrated circuits to the antenna itself to make active

antennas.


https://en.wikipedia.org/wiki/Active_antenna

https://en.wikipedia.org/wiki/Active_antenna

https://en.wikipedia.org/wiki/Microwave_integrated_circuit

https://en.wikipedia.org/wiki/Printed_circuit

https://en.wikipedia.org/wiki/Radio_frequency

https://en.wikipedia.org/wiki/Transmission_line

https://en.wikipedia.org/wiki/Microstrip

https://en.wikipedia.org/wiki/Radio_receiver

https://en.wikipedia.org/wiki/Transmitter

https://en.wikipedia.org/wiki/Ground_plane

https://en.wikipedia.org/wiki/Printed_circuit_board

https://en.wikipedia.org/wiki/Patch_antenna

https://en.wikipedia.org/wiki/Frequency

https://en.wikipedia.org/wiki/Microwave



https://en.wikipedia.org/wiki/Microstrip



Fig 1.7 Microstrip feed line

The frequency of operation of patch antenna is determined by the length L. The center frequency is given by:

f c =[c

2L√E r

¿=¿

The above equation says that the micro strip antenna should have a length equal to one half of a wavelength within the dielectric medium.

Advantages of Microstrip Antenna:

Microstrip antennas are relatively inexpensive to manufacture and design because of the

simple 2-dimensional physical geometry.

They are usually employed at UHF and higher frequencies because the size of the

antenna is directly tied to the wavelength at the resonant frequency.

A single patch antenna provides a maximum directive gain of around 6-9 dB

It is relatively easy to print an array of patches on a single (large) substrate using

lithographic techniques.

Patch arrays can provide much higher gains than a single patch at little additional cost;

matching and phase adjustment can be performed with printed microstrip feed structures,

again in the same operations that form the radiating patches.

The ability to create high gain arrays in a low-profile antenna is one reason that patch

arrays are common on airplanes and in other military applications.


https://en.wikipedia.org/wiki/Resonance

https://en.wikipedia.org/wiki/Wavelength

https://en.wikipedia.org/wiki/UHF


An advantage inherent to patch antennas is the ability to have polarization diversity.

Patch antennas can easily be designed to have vertical, horizontal, right hand circular

(RHCP) or left hand circular (LHCP) polarizations, using multiple feed points, or a single

feed point with asymmetric patch structures. This unique property allows patch antennas

to be used in many types of communications links that may have varied requirements.

Patch Antenna:

The most common type of microstrip antenna is the patch antenna. Antennas using patches as

constitutive elements in an array are also possible. A patch antenna is a narrowband, wide-

beam antenna fabricated by etching the antenna element pattern in metal trace bonded to an

insulating dielectric substrate, such as a printed circuit board, with a continuous metal layer

bonded to the opposite side of the substrate which forms a ground plane. Common microstrip

antenna shapes are square, rectangular, circular and elliptical, but any continuous shape is

possible. Some patch antennas do not use a dielectric substrate and instead are made of a metal

patch mounted above a ground plane using dielectric spacers; the resulting structure is less

rugged but has a wider bandwidth. Because such antennas have a very low profile, are

mechanically rugged and can be shaped to conform to the curving skin of a vehicle, they are

often mounted on the exterior of aircraft and spacecraft, or are incorporated into mobile

radio communications devices. It is used in telecommunication.

Fig 1.8 Patch antenna

CHAPTER 2


PATCH

https://en.wikipedia.org/wiki/Mobile_radio

https://en.wikipedia.org/wiki/Mobile_radio

https://en.wikipedia.org/wiki/Bandwidth_(signal_processing)

https://en.wikipedia.org/wiki/Ground_plane


https://en.wikipedia.org/wiki/Dielectric

https://en.wikipedia.org/wiki/Light_beam

https://en.wikipedia.org/wiki/Patch_antenna

https://en.wikipedia.org/wiki/Polarization_(waves)


LITERATURE SURVEY

An antenna is a device to transmit and/or receive electromagnetic waves. Electromagnetic

waves are often referred to as radio waves. Most antennas are resonant devices, which operate

efficiently over a relatively narrow frequency band. An antenna must be tuned (matched) to the

same frequency band as the radio system to which it is connected, otherwise reception and/or

transmission will be impaired.

Inspired by the theory and geometries of fractal antennas, we present a method in this paper

where T-shaped slots are loaded in the terminals of a T-shaped antenna. This method can make

the proposed structure realize multiple band operation in comparison with the original T-shaped

antenna. In order to identify the versatility of this method, two different feeding transmission

lines are respectively connected with the proposed structure. The effects of the key parameters

are studied so as to adjust the size of the antenna to get the desired results. The antenna detailed

parametric study are given. Both simulated and measured results for these antennas are given to

verify the feasibility of this method.

2.1. LITERATURE REVIEW:

A miniaturized Fermi tapered slot antenna for Ultra-Wide Band application is proposed in the

paper. Fermi tapering profile (FTP) and tapered slot load (TSL) are employed in the design. FTP

has the capacity to narrow radiation beam and maintain good directivity. TSL could extend the

impedance bandwidth by broking physical limitation and improve the radiation characteristics in

the lower frequencies as well. A prototype of the presented antenna has been fabricated and

experimentally studied. The measured results have demonstrated to have a impedance bandwidth

from 2.77 GHz to over 12 GHz. Highly directive patterns have also been observed in both E-

plane and H-plane.

In this study, a novel method for designing a new monopole antenna with dual band-notched

characteristic for UWB applications has been presented. The proposed antenna consists of a

square radiating patch with a modified T-shaped slot, and a ground plane with two E-shaped

slots and a W-shaped conductor backed-plane. By cutting two E-shaped slots in the ground

plane, additional resonance is excited and hence much wider impedance bandwidth can be



produced, especially at the higher band, which results in a wide usable fractional bandwidth of

more than 130% (2.73%13.3 GHz). In order to generate single band-notched characteristic, the

authors use a W-shaped conductor backed-plane structure on the other side of the substrate. In

addition, by cutting a modified T-shaped slot in the radiating patch and microstrip feed-line, a

dual band-notched function is achieved. The measured results reveal that the presented dual

notch band monopole antenna offers a very wide bandwidth with two notched bands, covering

all the 5.2/5.8 GHz wireless local area network, 3.5/5.5 GHz WiMAX and 4 GHz C bands. The

designed antenna has a small size of 12 % 18 mm2. Good voltage standing wave ratio (VSWR)

and radiation pattern characteristics are obtained in the frequency band of interest. Simulated and

measured results are presented to validate the usefulness of the proposed antenna structure for

ultra-wideband (UWB) applications.

A new planar monopole antenna that covers 3G, Bluetooth, WiMAX, and the UWB bands but

exhibits dual band-notched characteristic is presented. By etching one quasi-complementary

split-ring resonator (CSRR) in the feed line, dual notched frequency bands centered at 5.3 and

7.4 GHz are obtained. To achieve the lower resonance over the 3G band, the transmission-line-

based metamaterial (TL-MTM) loading is employed to gain the benefit that the radiation pattern

is orthogonal to other resonance modes. The proposed antenna has been successfully simulated

and measured. Experimental results indicate that the proposed antenna yields an impedance

bandwidth of 2-12.5 GHz with VSWR<2, except the dual notched bands of 5.0-5.5 and 7.2-7.6

GHz. Furthermore, good group delay and transmission characteristics can be achieved in the

UWB band.

A novel single-layer dual band-notched printed circle-like slot antenna for ultrawideband

(UWB) applications is presented. The proposed antenna comprises a circle-like slot, a trident-

shaped feed line, and two nested C-shaped stubs. By using a trident-shaped feed line, much

wider impedance bandwidth is obtained. Due to inserting a pair of nested C-shaped stubs on the

back surface of the substrate, two frequency band-notches of 5.1-6.2 (WLAN) and 3-3.8 GHz

(WiMAX) are achieved. The nested stubs are connected to the tuning stub using two cylindrical

via pins. Throughout this letter, experimental results of the impedance bandwidth, gain, and

radiation patterns are compared and discussed .



The research and development of ultra-wideband (UWB) technology has greatly spurred the

design of small broadband antennas. The requirements for the UWB antennas include consistent

impedance and radiation performance over an ultra-wide bandwidth of

3.1-4.8GHz/6-10.6GHz/3.1-10.6GHz. The miniaturization of the antennas becomes the most

critical design challenges in commercial UWB systems such as high-speed wireless USB

dongles. This course reviews the development of the small UWB antennas. The key design

issues of the UWB antennas such as planar printed UWB antennas are highlighted. The new

techniques to reduce the effect of ground plane on the antenna performance, to further

miniaturize antenna, and to co-design antenna with RF filters are elaborated. The latest

applications of small printed antennas in wireless UWB systems are described in brief.



CHAPTER 3

DESIGN AND METHODOLOGY OF DUAL-BAND NOTCHED ULTRA WIDEBAND MICROSTRIP ANTENNA:

3.1 GEOMETRICAL CONFIGURATION:

Wireless communications have progressed very rapidly in recent years, and many mobile

units are becoming smaller and smaller. To meet the miniaturization requirement, the antennas

employed in mobile terminals must have their dimensions reduced accordingly.

3.2 DESIGN METHODOLOGY:

As shown in Fig., top geometry of the proposed microstrip antenna is a semicircular patch

printed on a substrate with size of 32mm×30mm, thickness of 1.6 mm, and relative dielectric

permittivity of 4.5. A semicircular ground plane is on bottom of the substrate is shown in Fig.

1(b). The antenna is fed by a 50Ωmicrostrip line with length of 16.6mm and width of 2mm. The

radius of the semicircular metal patch is r=13mm. To realize the band notched property, a

rectangular complementary split ring is inserted in the radiating metal patch. The rectangular

complementary split ring is composed of two concentric square split rings with small cuts

etching in the semicircular metal plate, and the two splits are placed on opposite sides of each

ring. The complementary split ring is inspired on Babinet principle, and it also exhibits a quasi-

static resonance characteristic. The total dimension of a ring is approximately equal to half of the

guided wavelength at the rejection frequency. According to the center rejection frequency of

3.5GHz, the total length of the complementary split ring can be calculated to be 27 mm. After the

optimization by CST MWS, the appropriate position of the complementary split ring in the

radiating patch is shown in Fig. 1. The distance is 0.9mm between the split and the end of

microstrip line. The long side of the outer ring is a=8.9mm, and the short side of the outer ring is

b=4.5mm. The small gap of the outer ring is w=1mm, the width of the etching ring is g=0.2mm,

and the distance of the two rings is d=0.8mm.



Fig 3.1 A dual band notched ultra wideband micro strip antenna



CHAPTER 4

SIMULATED RESULTS AND DISCUSSIONS

4.1 INTRODUCTION TO HFSS:

The coplanar waveguide was invented in 1969 by Cheng P. Wen, primarily as a means by

which non-reciprocal components such as gyrator sand isolators could be incorporated in planar

transmission line circuits.

4.2 MODELLING IN HFSS:

1- Starting HFSS

- Click the Ansys Electronic Desktop button, Select Program

- Or Double click on the HFSS 17icon on the Windows Desktop.

2- Creating the Project:

First launch the HFSS Simulator0



From the Project Manager window. Right-Click the project file and select Save As from the sub

menu.

3- Working with geometries

To beginworkingwith geometries.

- you must insert an HFSS design. Right-Click the project file and select

Insert> Insert HFSS Design from the menu.

- Or click on the toolbars.



Due to the nature of this design we will use Driven Terminalas the solution type.

From the HFSS menu select Solution Typeand Driven Terminal.

.

The units are chosen as mm by choosing the heading 3D modeler and Units from the menu.



4- Drawing the Substrate:

We will start to by creating the substrate using the Draw Rectanglebutton from the toolbar.

By default the properties dialog will appear after you have finished drawing an object. The

position and size of objects can be modified from the dialog.



Now, design the antenna with respect to the calculated lengths to obtain the appropriate shape.



CHAPTER 5

RESULTS AND DISCUSSIONSThe following figure shows the Reflection coefficient of the designed antenna. In operating band

from 2.8GHz to 12GHz, two rejection bands can be found in 3.3GHz~3.7GHz and

5.15GHz~5.85GHz when the reflection coefficient is more than -10dB by etching a

complementary split ring metal patch. They can cover WiMAX and WLAN frequency bands

notched.

5.1 Reflection coefficient of the dual-band notched antenna



According to measured data, figure shows the patterns of E-plane on the rejection frequencies

of 3.6GHz and 5.8GHz respectively. The gain is -2.6dB at 3.6GHz and -0.5dB at 5.8GHz.

5.2.The patterns at the rejection frequencies 3.53GHz



The figure shows the radiation patterns of 3.1GHz , which as in working band. The gain is 2.4dB at 3.1GHz and 2.7dB at 8GHz

5.3. The patterns at the operating frequencies 3.11GHz



The below figure shows the 3D radiation polar plot with positive gain of 2.645GHz.

5.4. 3D Polar Plot

The figure shows the simulated gain of the antenna from 2.8GHz to 12GHz. It can be observed

that the realized gain decreases below 0dB at 3.5 GHz and 5.6 GHz, which shows the rejection

characteristic in 3.3GHz~3.7GHz and 5.15GHz~5.85GHz. While the gain is 2.3~6.3dB in

working frequency band.

5.5 Gain at different frequencies



CHAPTER-6

CONCLUSION

This paper presents a kind of ultra wideband microstrip antenna with dual-band notched by

etching a complementary split ring in semicircular radiating patch. Two rejection bands are

achieved of 3.3GHz~3.7GHz and 5. 15GHz~5.85GHz with the reflection coefficient more than -

10dB. In the stop band the gain is less than 0dB, while the gain is more than 2dB in working

band. The patterns in H-plane show nearly omnidirectional radiation characteristic. Experimental

results show the proposed antenna will be promising for practical dual-band notched

applications.



REFERENCES

1. J. Yoon, H. Kim, H. K. Yoon, Y. J. Yoon, Y. -H. Kim, "Ultra-wideband tapered slot

antenna with band cutoff characteristic", Electronics Letter, vol. 41, no. 11, pp. 629-630,

2005.

2. M. Mchranpour, J. Nourinia, Ch. Ghobadi, M. Ojaroudi, "Dual band-notched square

monopole antenna for ultra wideband applications", IEEE Antennas and Wireless

Propagation Letters, vol. 11, pp. 172-175, 2012.

3. N. Ojaroudi, M. Ojaroudi, N. Ghadimi, "Dual band-notched small monopole antenna

with novel W-shaped conductor backed-plane and novel T-shaped slot for UWB

applications", IET Microwave Antennas &Propagation, vol. 7, no. 1, pp. 8-14, 2013.

4. Wen Tao Li, Yong QiangHei, Wei Feng, Xiao Wei Shi, "Planar antenna for

3G/Bluetooth/WiMAX and UWB applications with dual band-notched

characteristics", IEEE Antennas and Wireless Propagation Letters, vol. 11, pp. 61-64,

2012.

5. SeyedRaminEmadian, Changiz Ghobadi, JavadNourinia, Mir Hamed Mirmozafari,

JavadPourahmadazar, "Bandwidth enhancement of CPW-fed cirel-like slot antenna with

dual band notched characteristic", IEEE Antennas and Wireless Propagation Letters, vol.

11, pp. 543-546, 2012.

6. Lee Dae-Heon, Yang Hae-Yong, Cho Young-Ki, "Tapered slot antenna with band-

notched function for ultra wideband radios", IEEE Antennas and Wireless Propagation

Letters, vol. 11, pp. 682-685, 2012.




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