Abstract
The design of multiband antenna by a single microstrip antenna is observed in this paper.It is designed with three band central frequency.In this design we use the new technique of inserting rectangular and triangular slots. The antenna is suitable for frequencies 2.36 GHz, 2.8 GHz & 4.41 GHz.Also size of antenna was reduced to increase its performance.This type of antenna has different mobile communication applications such as WLAN,Bluetooth etc.
Introduction
Microstrip patch antennas are largely used because of their many applications. But patch antennas have a main disadvantage: narrow bandwidth. Researchers have taken many steps to conquer this problem and
many solutions have been put forward to enhance the bandwidth [6].
In recent times, the radio communication sector about the people using the mobile telecommunication terminals has been developed immensely.
The minimization, efficiency, and precision of the mobile phone's antennas will be seen as new design technologies evolution. The predictable functioa bandwidth and on the design of multifunction operations . As a result, almost 100 percent bandwid and dual-band operations fo GSM 900 and GSM
1800 services have been successfully achieved . Along with this revived interest on the applications of microstrip antennas development of efficient an accurate simulation equipment to help and design such antennas has gained some value as well. The cavity model has a special place for providing physical insight on the electrical characteristics and radiation mechanism of microstrip antennas, in addition to better performance as compared to the transmission line model, and better computational efficiency a compared to the full-wave approaches . So, the cavity model is often used to design and analyze the first trial antenna, and then the fine-tuning is performed with a full-wave technique, like HFSS. Since the cavity model is numerically quite efficient and capable of handling variety of microstrip antennas with shorting pins and slots, when it is coupled with a suitable optimization algorithm, the combination would be very efficient and effective design equipment, at least during the starting phase of the design. During this study, an algorithm was chosen as the suitable optimization. The antenna has been proposed to realize various functionalities such as dual frequency operation, dual band performance. Mobile communications have been essential in modern life.
There are different types of communication systems, such as the global positioning system (GPS) and digital communication system (DCS), designed to fulfil various requirements[1]. The GPS provides global positioning system via satellites and the DCS provides personal mobile communication services . Because of different radiation performances
of the GPS and DCS, dual-band antennas with single radiation characteristics are not practical for the GPS/DCS applications.
Specifications
A new approach is used, that combines a rectangular patch (30x40 mm) with a triangular patch of same area (base=30 mm and height h=80 mm).The antenna is suitable for frequencies 2.36 GHz, 2.8 GHz & 4.41 GHz .The substrate material is polyflon norclad, with a dielectric constant 2.55 & having dimensions width= 60mm, length= 150mm & height= 3.2mm. Ground as well as patch is assigned Perfect E, which means no material is specified. The ground has same dimensions as substrate.
Top view
Side view figure1(b).antenna
A triangular slot is inserted inside triangular patch with base= 15 mm & height= 12 mm.
Probe feed mechanism is used to provide excitation to the antenna.
For this purpose, a circle (radius>0.5 mm) is subtracted from the ground & a cylinder (radius=0.5mm & height=3.2mm, material copper) is inserted into the substrate through this circle. Also, a cylinder of same dimensions is inserted reciprocally at opposite z-axis.
The downward cylinder is encrusted in another vacuum cylinder with same height & larger radius.
Excitation vector is assigned, such that the tail of the vector is at the starting of vacuum cylinder & vertex at copper cylinder.
Results
In this paper design and analysis of the multi-band microstrip patch antenna has been performed The antenna is suitable for frequencies 2.36 GHz, 2.8 GHz & 4.41 GHz.
As only three-band operation has been shown by each different slot-shaped in this paper, it is possible to make further enhancement to the results of a multi-band antenna by using more air gaps.Bandwidth has increased as shown by Figure2.
Return loss is calculated through HFSS.And at a central frequency of 4.41GHz, the return loss is calculated to be -28 dB.As two more bands are added after we used the feeding techniques. Before this was a single band antenna .Now, it has become a triple band antenna.Before enhancement was made return loss was calculated to be -30dB at 3GHz central frequency.As far as gain is concerned it comes out to be 6.422dBat the resonant frequency in GHz.
Figure 4, Radiation pattern
Conclusions
In this paper, the small three-band microstrip patch antennas are shown. The antenna is designed to be used in multi-band system applications, covering the RF and the mobile Communication range. Concept behind the design is the addition of rectangular slots considering a Chebychev method. The triangular patch used has the similar sort of area as the rectangular patch. The antenna can operate for applications of GSM, GPS, WI-FI Video Wireless Communication, Bluetooth devices etc.
