Cross Slot Microstrip Patch Antenna with dual Polarization Essay

CROSS SLOT MICROSTRIP PATCH ANTENNA WITH DUAL POLARIZATION
Nazia Hasan
Student ECE Deptt, UTU Dehradun
Uttarakhand Technical University, Dehradun
Dehradun, India
nazia_hasan6@yahoo.co.in
Dr.S.C.Gupta
ECE Deptt, DIT Dehradun
Dehradun Institute of Technology Dehradun
Dehradun, India
sureshprem1938@gmail.com
Abstract- A single-feed circular microstrip patch antenna with reconfigurable polarization capability is proposed. This proposed antenna has a very simple structure two slots are created at an angle of 45 degree and 135 degree in the shape of X at the centre of patch antenna, and one Micro Electromechanical switch is inserted at the centre of the created slot to alter the polarization of antenna. When switch is in ON position the polarization will be linear and if switch is OFF polarization will be circular. Polarization will be confirmed with the help of axial ratio plot. Microstrip feed line is used in this structure.
Keywords-Circular Polarization, microstrip patch, Xshape slot, MEM switch
I. INTRODUCTION
Micro-strip patch antennas have always been a very attractive choice for the researchers, because of its numerous advantages such as low volume, light weight, low cost, ease of construction conformal configuration, compatibility with integrated circuits and so many others. Mostly micro-strip patch antennas are designed for linear polarization, but in some applications such as satellite communication circular polarization is desired because of its insensitivity to transmitter or receiver orientation. Polarization diversity [2] may be a great issue in effectively addressing the multipath-fading effects in recent wireless communication systems [3].
A micro-strip patch antenna is one of the most widely used radiator which is used to generate circular polarization. Circular polarized operation and polarization diversity are becoming major design concerns for practical applications of micro-strip patch antennas. Polarization diversity may be an issue in effectively addressing the multipath-fading effects in modern wireless communication systems
In the work presented in this paper a micro-strip patch antenna is designed at 3.6 GHz that is linearly polarized [10]. Two crossed slots in the shape of 'X' created at the centre of patch antenna, as a result of which the linear polarization of the antenna is converted to circular polarization. In this way circular polarization is achieved [4]. This antenna is converted to reconfigurable antenna by inserting a MEM switch at the center of x shape slot. The cross slot etched antenna shows two types of polarization, the polarization is linear at switched on position and the polarization is circular at switched off position [1]. In this way the cross slot etched antenna provides dual characteristics.
Table 1 shows the design parameters of simple micro-strip patch antenna without any slot [5].
II. ANTENNA DESIGN
S.No. Parameter Value
1. Frequency 3.6 GHz
2. Dielectric constant of substrate Duroid(tm) 2.2
3. Width of patch 22.58 mm
4. Length of patch 22.58 mm
5 Type of feed Stripline feed
6. Width of quarter wave transformer 0.582 mm
7. Length of QWT 20.8325 mm
8. Width of 50 ohm transmission line 4.84 mm
9. Length of 50 TL 15 mm
10. Slot length 8.6mm
11. Slot width 0.86mm
12 Polarization Linear