ANALYSIS OF UWB BASED ANTENNA FOR WIRELESS COMMUNICATION

Ultra-wideband wireless communications techniques have many merits, including an extremely simple radio that inherently leads to low-cost design, large processing gain for robust operations in the presence of narrowband interference, covert operations, and fine time resolution for accurate position sensing. However, there are a number of challenges in UWB receiver design, such as capturing multipath energy, inter symbol interference especially in a non-line-of-sight environment, and the need for high-sampling-rate analog-to-digital converters. Microstrip Patch antenna (MPA) provides low profile and low volume, so it is use in a now a days communication devices. In this paper study of past few year shows that most of labour on MPA is targeted on planning compact sized microstrip antenna. A novel ultra-wideband printed monopole antenna can be used in wireless communication devices.


Introduction
An antenna is used for both transmitting and receiving the information so it is the essential part of the microwave communication. It is a device that is made to efficiently radiate and receive the radiated electromagnetic waves. Antenna is a transducer which converts the voltage and current on a transmission line into an electromagnetic field in a space, consisting of an electric and magnetic field travelling right angles at each other. In microwave imaging systems, over the full operative band one of key issues is that the style of a compact antenna whereas providing wideband characteristic. It is a well-known incontrovertible fact that placoid monopole antennas physical options, like easy structure, little size and low price present very appealing. Consequently, variety of planner monopoles with totally different geometrics are through an automatic style strategies and experiment characterized have been developed to attain the optimum placoid form. With the event of band wireless communication systems, ultra wide band (UWB) systems have been increasing quickly. The Federal Communications Commission allotted the wave band 3.1~10.6 GHz for the UWB services. These UWB systems have been used for radiolocation applications, localization, information communications etc. The antennas of UWB systems area unit embedded into these transmission devices, the house networking system is wide utilized in transmission devices like HDTV's, DVD's, cameras and private computers through the UWB service channels. The most commonly employed microstrip patch antenna is a rectangular patch. The rectangular patch antenna is approximately a one wavelength long section of rectangular microstrip transmission line. Microstrip resonators will be classified into two sorts counting on the length and width of antennas. Resonators with a slim conductor known as microstrip dipole and resonators with a large conductor are referred to as microstrip patch. When the signal frequency is within the section of a resonance, a microstrip resonator radiate comparatively broad beam, broadside to the plane of the substrate. A serious a part of the sign participates in radiation and so the resonator acts as an antenna. Since patch dimensions should be of the order of a radio-controlled wavelength, its directivity is extremely low as an example, a half-wavelength dipole generally features a gain of regarding 5-6 db. and beam width between 70 and 90 degrees.

Literature Review
The construction of microstrip patch antenna with conducting patch on a ground plane separated by insulator substrate was undeveloped till the revolution in electronic circuit shrinking and large-scale integration in 1970. After that several mortal have drawn the radiation from very

Antenna Design Parameters
There are three essential parameters for design of a rectangular Microstrip Patch Antenna. Firstly, the resonant frequency (f 0 ) of the antenna must be selected appropriately. The frequency range for ultra wide band applications is 3.1 to 10.6 GHz and the design antenna must be able to operate within this frequency range. Second important parameter of antenna is substrate thickness. The height of dielectric substrate employed in this design of antenna is h= 1.6mm.Third important parameter of good antenna design is dielectric substrate (ℇr). A thick dielectric substrate having low dielectric constant is desirable. This provides better efficiency, larger bandwidth and better radiation. The look of patch is going to be fed by a microstrip transmission line. Patch will act as a conductor. This structure of the antenna having length of patch L, width W , height of dielectric substrate H and Loss tangent. The antenna parameters antenna can be calculated as exemplified below:

Width of Patch
Where c= speed of light in free space

√
Where le= effective length

Ground Dimension
For practical considerations, it is essential to have a finite ground plane.
If the size of the ground plane is greater than the patch dimensions by approximately six times the substrate thickness all around the periphery then it is given by the formula:-

Feed Location
To radiate the antenna, a feed is used to excite by direct or indirect contact. The feed of microstrip antenna can have many configurations like microstrip line, coaxial, aperture coupling and proximity coupling. But to fabricate easily microstrip line and the coaxial feeds are relatively used.
Coaxial probe feed is used because it is easy to use and the input impedance of the coaxial cable in general is 50Ω.

Results and Analysis
Result and analysis of previous literature papers is given below:- Modified ground plane with pairs of L-shaped slits and parasitic Structures [1] Bandwidth of more than 130% (2.95 -14.27 GHz) radiation efficiency is greater than 86% 2.
VSWR and Radiation Pattern [3] Return loss of -29.2133 dB at 1.8 GHz

3.
Inverted U -shaped slots and two L-shaped parasitic elements [5] Bandwidth of more than 130% & good Omnidirectional radiation pattern 4. I-shaped slot on the feed -line and a pair of S -shaped slots in the ground plane [8] Wider impedance bandwidth & radiation efficiency is greater than 82%

Conclusion
This review paper shows study of the Microstrip Patch Antenna using UWB frequency ranges for Wireless communication devices applications. After study of literature survey it is concluded that multi resonance characteristics of MPA such as Return loss, VSWR, Radiation pattern, Impedance bandwidth can be improved by changing the parameters such as operating frequency, ground plane structure dimensions, feeding techniques.