im quite new to antena world, what i could understand is the polarization of antenna. I have trouble understanding it. eg if im designing patch microstrip antenna hw do i determine the polarization of antenna whether circular or else. Can any one explain in simple way for me to get it as the books confuse me.
Polarization is simple words is the direction of the wave transmitted from your antenna.
Usually the shape of your antenna is the main character to tell the polarization. If it's a plane surface.. It's straight polarization and a round surface such as for dipole give 360° poalrization. FOr circular microstrip the polarization is also 360°.
Picture it as a spring that u stretch. The wave travel from one point to the other end following the line of the spring
The polarization of an antenna, is given by the following definition:
The polarization of an electromagnetic field expresses the curve that the electric field vector depicts as a function of increasing time at a fixed point in the far field
So if you have an simple half-wave dipole and align it along the z-axis, you can find in any antenna book the expressions for the E and H-field. If you take a look at the electric field and in the far field region, then it only has a Θ-component this means that if you look at the z-axis then the E-field will go up and down along the z-axis making it a linearly polarized antenna.
A microtrip-patch antenna can be polarized both left and right hand. This is determined by how you feed and how many feed points you have.
If you are new to the antenna world then take a look in the following books:
Antenna theory by Balanis
or
Antenna theory and design by stutzman & Thiele