• U Slot Antenna Signal
• U Shaped Slot Antenna

The double modified U slots planar patch antenna is designed, simulated and fabricated to operate at 2.8 GHz (between 2.794 to 2.846 GHz), at 3.1 GHz (between 3.145 to 3.196 GHz), at 3.6 GHz. You can improve your winning Design Of U Slot Microstrip Patch Antenna chances by doing one of several Design Of U Slot Microstrip Patch Antenna things. Firstly, you should never gamble with money that you cannot afford to lose. Always quit when you are ahead and never gamble to win back any losses. Patch antenna, Double U-slot antenna, WiMAX antenna, GEMS software simulink. —————————— —————————— 1 INTRODUCTION microstrip antenna consists of a dielectric substrate, with a ground plane on the other side. The microstrip patch antenna is very well suited for applications such as wireless.

A slot antenna consists of a metal surface, usually a flat plate, with one or more holes or slots cut out. When the plate is driven as an antenna by an applied radio frequency current, the slot radiates electromagnetic waves in a way similar to a dipole antenna. The shape and size of the slot, as well as the driving frequency, determine the radiation pattern. Slot antennas are usually used at UHF and microwave frequencies at which wavelengths are small enough that the plate and slot are conveniently small. At these frequencies, the radio waves are often conducted by a waveguide, and the antenna consists of slots in the waveguide; this is called a slotted waveguide antenna. Multiple slots act as a directivearray antenna and can emit a narrow fan-shaped beam of microwaves. They are used in standard laboratory microwave sources used for research, UHF television transmitting antennas, antennas on missiles and aircraft, sector antennas for cellular base stations, and particularly marine radar antennas. A slot antenna's main advantages are its size, design simplicity, and convenient adaptation to mass production using either waveguide or PC board technology.

Structure[edit]

As shown by H. G. Booker in 1946, from Babinet's principle in optics a slot in a metal plate or waveguide has the same radiation pattern as a driven rod antenna whose rod is the same shape as the slot, with the exception that the electric field and magnetic field directions are interchanged; the antenna is a magnetic dipole instead of an electric dipole; the magnetic field is parallel to the long axis of the slot and the electric field is perpendicular. Thus the radiation pattern of a slot can be calculated by the same well-known equations used for rod element antennas like the dipole. The waves are linearly polarized perpendicular to the slot axis. Slots up to a wavelength long have a single main lobe with maximum radiation perpendicular to the surface.

Antennas consisting of multiple parallel slots in a waveguide are widely used array antennas. They have a radiation pattern similar to a corresponding linear array of dipole antennas, with the exception that the slot can only radiate into the space on one side of the waveguide surface, 180° of the surrounding space. There are two widely used types:

• Longitudinal slotted waveguide antenna - The slots' axis is parallel to the axis of the waveguide. This has a radiation pattern similar to a collinear dipole antenna, and is usually mounted vertically. The radiation pattern is almost omnidirectional in the horizontal plane perpendicular to the antenna over the 180° azimuth in front of the slot, but narrow in the vertical plane, with the vertical gain increasing approximately 3 dB with each doubling of the number of slots. The radiation is horizontally polarized. It is used for vertical omnidirectional transmitting antennas for UHF television stations. For broadcasting, a cylindrical or semicircular waveguide is sometimes used with several columns of slots cut in different sides to give an omnidirectional 360° radiation pattern.
• Transverse slotted waveguide antenna - The slots are almost perpendicular to the axis of the waveguide but skewed at a small angle, with alternate slots skewed at opposite angles. This radiates a dipole pattern in the plane perpendicular to the antenna, and a very sharp beam in the plane of the antenna. Its largest use is for microwave marine radar antennas. The antenna is mounted horizontally on a mechanical drive that rotates the antenna about a vertical axis, scanning the antenna's vertical fan-shaped beam 360° around the water surface surrounding the ship out to the horizon with each revolution. The wide vertical spread of the beam ensures that even in bad weather when the ship and the antenna axis is being rocked over a wide angle by waves the radar beam will not miss the surface.

History[edit]

The slot antenna was invented in 1938 by Alan Blumlein, while working for EMI. He invented it in order to produce a practical type of antenna for VHF television broadcasting that would have horizontal polarization, an omnidirectional horizontal radiation pattern and a narrow vertical radiation pattern.^[1][2]

Prior to its use in surface search radar, such systems used a parabolic segment reflector, or 'cheese antenna'. The slotted waveguide antenna was the result of collaborative radar research carried on by McGill University and the National Research Council of Canada during World War II.^[3] The co-inventors, W.H. Watson and E.W. Guptill of McGill, were granted a United States patent for the device, described as a 'directive antenna for microwaves', in 1951.^[4]

Other uses[edit]

In a related application, so-called leaky waveguides are also used in the determination of railcar positions in certain rapid transit applications. They are used primarily to determine the precise position of the train when it is being brought to a halt at a station, so that the doorway positions will align correctly with queuing points on the platform or with a second set of safety doors should such be provided.

See also[edit]

• Microwave Radiometer (Juno) (has a slot array antenna)
• RIMFAX (radar for Mars rover has slot antenna design)

References[edit]

1. ^Blumlein, Alan (1938-03-07), 'Improvements in or relating to high frequency electrical conductors or radiators', British patent no. 515684
2. ^Burns, Russell (2000). The life and times of A.D. Blumlein. Institution of Engineering and Technology. ISBN0-85296-773-X.
3. ^Covington, Arthur E. (1991). 'Some recollections of the radio and electrical engineering division of the National Research Council of Canada, 1946-1977'. Scientia Canadensis: Canadian Journal of the HIstory of Science, Technology and Medicine. 15 (2): 155–175. doi:10.7202/800334ar.
4. ^Watson, William Heriot; Guptill, Ernest Wilmot (6 November 1951), Directive Antenna for Microwaves, retrieved 20 December 2016

External links[edit]

• 'Slot Antennas'. Antenna Theory.
• Slotted Waveguide Antennas Antenna-Theory.com

International Journal of Scientific & Engineering Research, Volume Ś, Issue ŝ, ž•¢-201ř

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1469

Design & Simulation of Double U-Slot Microstrip

Patch Antenna for WiMAX Application

Md. Suaibur Rahman1, Md. Munjure Mowla2, Md. Mahabub Alam3

Abstract— This paper presents the numerical simulation of double U-slots microstrip patch antenna for W iMAX application. The proposed antenna is feed by the Transmission line. The total area occupies by the antenna 40mmx47mm. In this design two slots and one bridge ele ments have been ap- plied to generate the three frequencies bands 2.44GHz, 3.26GHz and 5.38GHz respectively. In addition, the antenna has achievable return l oss, radia- tion pattern and also bandwidths within the -8dB return loss bandwidth. The bandwidths of the three frequencies band are 4.22%, 1.87% and 3.51%

respectively. The return loss S11 characteristic for the three band are -24dB, -20dB and -47dB respectively. Due to the compact area occupied, the pro- posed antenna is promising to be embedded within the different portable devices employing W iMAX applications.

U Slot Antenna Signal

Index Terms— Patch antenna, Double U-slot antenna, W iMAX antenna, GEMS software simulink.

——————————  ——————————
microstrip antenna consists of a dielectric substrate, with a ground plane on the other side. The microstrip patch antenna is very well suited for applications such as wireless communication system, cellular phone, radar system and sa- tellite communication system [1], [2]. The IEEE 802.16 working group has established a new standard known as WiMAX (Worldwide Interoperability for Microwave Access) which can reach a theoretical up to 30- mile radius coverage. Moreover, in the case of WiMAX, the highest theoretically achievable transmission rates are possible at 70 Mbps. One of the poten- tial applications of WiMAX is to provide backhaul support for mobile WiFi hotspots. A low profile double U-slots antenna for WiMAX operation has low return loss and bandwidth. Recently, proposed printed antenna for WiMAX operation has the three frequencies bands but the return loss not over -30dB [3]. The broadband characteristic of a microstrip patch antenna with U-shaped slot has been confirmed by many published results [4], [5]. Also, several designs of broadband slots anten- na have been reported [6], [7]. A monopole antenna for Wi- MAX applications was proposed in [8]. In this paper, two slots and one bridge elements have been applied to generate the three frequencies bands to be used in WiMAX technology. Basically WiMAX has three allocated frequency bands called low band, middle band and high band. The low band has fre-

————————————————

 Md. Suaibur Rahman is with the Electronics and Telecommunication Engi- neering Department in Rajshahi University of Engineering & Technology (RUET), Rajshahi-6204, Bangladesh. (Corresponding author to provide phone:

+88-01723644003; e-mail: suaiburruet@gmail.com).

 Md. Munjure Mowla is with the Electronics and Telecommunication Engi-

neering Department in Rajshahi University of Engineering & Technology

(RUET), Rajshahi-6204, Bangladesh. (E-mail: rimonece@yahoo.com).

 Md. Mahabub Alam is with the Electronics and Telecommunication Engineer-

ing Department in Rajshahi University of Engineering & Technology (RUET),

Rajshahi-6204, Bangladesh. (E-mail: mahbub.ete@gmail.com).

quency from 2.4 GHz to 2.8 GHz, the middle band has fre- quency from 3.2 GHz to 3.8 GHz and the high band has
5.2GHz to 5.8 GHz. This paper addresses the numerical analy- sis of the proposed antenna for WiMAX operation with ac- ceptable return loss, gain and bandwidth. For the numerical analysis we consider the substrate permittivity of the antenna is r =4.4(FR4) with substrate thickness 1.2mm and feed by a 50
Ω microstrip line. The analysis is performed numerically using
GEMS software.
The paper is divided as follow: Section 2 discusses the antenna design and structure; Section 3 presents the parameter study; Section 4 explains the simulation process for the antenna and Section 5 conclusions.

In this paper several parameter have been investigate using GEMS software. The design specifications for the patch anten- na are:
 The dielectric material selected for the design is FR4.
 Dielectric constant 4.4
 Height of substrate (h) = 1.2 mm.
The antenna is fed by 50 Ω microstrip line, the main advantage of using transmission line feeding is very easy to fabricate and simple to match by controlling the inset position and relatively simple to model [3]. The proposed antenna has two U-slot shaped and one bridge to connect both shapes together as shown in Fig.1, the detailed dimensions are given in Table-1.

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3.1 The effect of changing width of W

In Fig.3, it shows the return loss based on variation in the width of the second U-slot (W) from 30 mm to 35 mm and to
40 mm. The first and second bands are not affected by the width of the second U-slot.

Changing the width (w)

0

-10

-20

-30

-40

-50

w=30 w=35 w=40

2 2.5 3 3.5 4 4.5 5 5.5

Fig.1 The geometric view of the proposed patch antenna

Frequency (GHz)

Fig.3 The effect of the increasing the width of W

9

x 10

The proposed antenna generates three bands at 2.44, 3.23 and
5.38 GHz with simulated impedance bandwidth of 4.22%,

TABLE 1

THE DIMENSION OF THE U-SLOTS ANTENNA (UNIT=MM)

1.87% and 3.51% respectively. Thus the three bands satisfied the required bandwidth for the WiMAX compliant transmit- ters.

S-parameter

0

-5

When 30mm width is used then first band and second band return loss increasing but third band decreasing. Again when we are used 40mm width then first band and third band re- turn loss increasing but second band decreased and band- width also decreasing. Finally, when we are sued 35mm width then three band return loss and bandwidth increasing. The good characteristic of the return loss and the bandwidth is obtained (W) 35 mm.

3.2 The of changing width of bridge C2

In Fig.4, it is describes the return loss based on increasing and decreasing the width (C2) of the first U-slot. Bridge width af- fects the bandwidth of the resonance frequency and return loss. When bridge width is sued 2.5mm then return loss is in- creased but bandwidth is decreased. When bridge width is

-10

-15

-20

-25

-30

-35

-40

-45

Excitation/ S-parameter

sued 4mm then bandwidth is increased but return loss is de- creased. Again, when we are used bridge width 3mm then return loss and bandwidth also increased. The good characte- ristic of the return loss and the bandwidth is obtained (C2) 3 mm.

Changing width of Bridge (C2)

0

2 2.5 3 3.5 4 4.5 5 5.5

-10

Frequency(GHz)

Fig.2 The return loss simulation result with two U-slots

9

x 10

-20

C2= 2.5 mm

C2=3 mm

C2=4 mm

As show in Fib.2 the simulation indicates a response at 2.44
GHz with return loss = - 24 dB, 3.26GHz with return loss = -20
dB and 5.38 GHz with return loss = -47 dB. The bandwidths of
the dual band are 4.22 %, 1.87% and 3.51 % respectively.

-30

-40

-50

2 2.5 3 3.5 4 4.5 5 5.5

There are some parameter that effect the antenna performance,

Frequency(GHz)

Fig.4 The effect of increasing the width of bridge (C2)

9

x 10

two of them have a very noticeable effect in the determining the performance of the antenna. The two parameters that
show the most effect are width of the W and width of the bridge. The return losses are different according to parameter changes. These effects will be explained and summarized in this section.
The radiation patterns at the centre frequencies 2.44GHz,
3.26GHz and 5.38GHz of WiMAX application are plotted as
shown in Fig.5 (a)-(c). The 3D radiation pattern at the center
frequencies 2.44GHz, 3.26GHz and 5.38GHz are plotted as
shown in Fug.6 (a)-(c).

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Fig.5 (a) Radiation pattern E-plane and H-plane at 2.44GHz

Fig.5 (b) Radiation pattern E-plane and H-plane at 3.26 GHz

Fig.5 (c) Radiation pattern E-plane and H-plane at 5.38 GHz

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Fig.6 (a) 3D Radiation pattern at 2.44GHz Fig.6 (b) 3D Radiation pattern at 3.26 GHz Fig.6 (c) 3D Radiation pattern at 5.38 GHz

tively. The U- slot patch antenna is designed for increasing the bandwidth and return loss but gain cannot increase. If array of the U- slot patch antenna is used then the gain can be im- proved. Therefore, the antenna will be better work in the Wi- MAX applications and wireless communications system.

REFERENCES

[1] W.L. Stutzman and G.A. Thiele, Antenna Theory and Design, 2nd ed.

U Shaped Slot Antenna

New York: Wiley, 1998.

[2] C.A. Balanis, Antenna Theory, 2nd Ed. New York: John Wiley & sons, Inc., 1997.

[3] Hattan F. Abu Tarboush, D. Budimir, R. Nilavalan “Connected U - slots Patch Antenna for WiMAX Applications”. International Journal of RF & Microwave CAF, 2008.

[4] H. F. AbuTarboush, H. S. Al-Raweshidy, “A Connected E-Shape and U-Shape Dual- Band Patch Antenna for Different Wireless Applica- tions”, the Second International EURASIP Workshop on RFID Tech- nology, July, 2008.

[5] M. Sanad, “Double C-patch antennas having different aperture shapes,” in Proc. IEEE Antennas and Propagation Dig., June 1995, pp.2116–2119.

[6] Murad NA. “Microstrip U-shaped dual-band antenna,” Applied

Electromagnetic, 2005 APACE 2005 Asia-Pacific Conference on

2005:4 pp

[7] Hadian AM. “Wideband rectangular microstrip patch antenna with U-slot,” Antennas and Propagation, 2007 EuCAP 2007 The Second European Conference on. 2007:1-5.

[8] T. liu and L. L. Wong, “A wideband Stubby Monopole Antenna and a GPS for WiMAX Mobile Phone with E911 Function,” Microwave and Optical Technology Letter, Vol 46, 2005, pp. 485-487.

This paper presented the simulation of the maicrostrip patch antenna with double U-slots. From two U- slots shape on the patch, the three bands can be generated and by adding one bridge the exact frequencies band for WiMAX can be achieved. The three frequency band 2.44GHz, 3.26GHz and 5.38GHz has been achieved as well as the bandwidth requirements for Wi- MAX standards 4.22%, 1.87% and 3.51% respectively. The re- turn loss for the triple band are -24dB, -20dB and -47dB respec-

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