Design of Microstrip Rectangular 8x1 Patch Array Antenna for WiMAX Application

. : In our daily lives, wireless communications are becoming increasingly significant. The antennas needed for these applications should be light weight, conveniently mountable, and have a broad bandwidth due to the rise in data rates and a tendency of tiny electronic devices for wireless digital applications. These requirements can be met by Microstrip Array Antennas . In this paper, the rectangular microstrip patch array antenna of frequency 2.5-3.5Ghz for WIMAX applications is designed in computer stimulation tool (CST). The antenna is fabricated using FR-4 Substrate material. The designed antenna's performance is analysed in terms of voltage VSWR, s-parameters, radiation pattern, gain, directivity.


Introduction
Advancement of technology for communication has significantly risen and shows no signs of slowing down, not the least of which is the wireless communication system. The popularity of wireless communication systems like Cellular Communication and WiMAX (Worldwide interoperability Mobile Access) as well as their service applications is growing alongside the development of advanced technology. These systems have a number of advantages over other types of technology, including the ability to offer users communication services at any time and from any location. Such wireless communication systems require communication equipment that can achieve preset standards in order to facilitate the transfer of data, voice, and multimedia with high speed access from base station to client. Antennas with high board bandwidth, low weight, high efficiency, and gain are required for these applications. It can be achieved using microstrip patch array antennas, which offer numerous advantages over a single microstrip antenna. The paper is structured as follows. Section 2 focuses about the physical description of an antenna. Parameter analysis is covered in section 3 whereas simulation in CST is covered in section 4. Results are discussed in section 5 and the conclusion is then presented.

Physical Description
The single elements and arrays of microstrip antennas are used. Using an array in communication systems allows us to improve the antenna's performance in terms of gain, directivity, beam scanning, and other tasks that are challenging to do with a single element.

Single Element Microstrip Antenna Design
A microstrip antenna consists of a ground plane on one side of a dielectric substrate which has a radiating metal patch on the other side.

Microstrip Patch Array Antenna Design
The feed network is used for designing eight element array networks.  Calculation process of microstrip patch antenna . At first, a 2.6 GHz operational frequency that ranges from 2-4 GHz has been chosen. Width of the patch was computed from Equation-1, using the operating frequency (fr), dielectric constant (r), and Velocity of Light(Co).
The Effective Dielectric Constant, εreff has also been calculated using Equation (2).
'h' represents substrate's height, and w represents the size of the patch. Effective Length (Leff) can be calculated using Equation (3).
Computing the ∆L-length extension's Because of the effect of fringe, the microstrip patch antenna seems longer than its actual length.
As a result, the effective length is ∆L shorter than the actual length. Measurement of the patch's actual length. By deducting the effective length from the length of∆ L's extension, we may determine the real length.

Simulation on CST
Firstly, we designed single element microstrip antenna. Further we designed 8X1 MICROSTRIP PATCH ARRAY ANTENNA. The following are images captured in cst.    Line width 2 Feed length total Line width 3

Results
The figures below shows the results of designed microstrip array antenna.

VSWR
The voltage standing wave ratio evaluates the efficiency with which radio-frequency power delivered from a source to a load over a transmission line.

Conclusion
We proposed a 8x1 Microstrip patch array antenna design and analysed its operational characteristics. A growing number of wireless communication applications are using 8x1 Microstrip array antennas due to their benefits. This study has covered the antenna's design specifications.