Presentation is loading. Please wait.

Presentation is loading. Please wait.

Polarization: Why do we care?? Antenna applications – – Antenna can only TX or RX a polarization it is designed to support. Straight wires, square waveguides,

Similar presentations


Presentation on theme: "Polarization: Why do we care?? Antenna applications – – Antenna can only TX or RX a polarization it is designed to support. Straight wires, square waveguides,"— Presentation transcript:

1 Polarization: Why do we care?? Antenna applications – – Antenna can only TX or RX a polarization it is designed to support. Straight wires, square waveguides, and similar rectangular systems support linear waves (polarized in one direction, often) Round waveguides, helical or flat spiral antennas produce circular or elliptical waves. Remote Sensing and Radar Applications – – Many targets will reflect or absorb EM waves differently for different polarizations. Using multiple polarizations can give different information and improve results. Absorption applications – – Human body, for instance, will absorb waves with E oriented from head to toe better than side-to-side, esp. in grounded cases. Also, the frequency at which maximum absorption occurs is different for these two polarizations. This has ramifications in safety guidelines and studies. Cruz-Pol,ECE Dept. UPRM

2 Polarization In general, plane wave has 2 components; in x & y And y-component might be out of phase wrt to x-component,  is the phase difference between x and y. Cruz-Pol,ECE Dept. UPRM x y EyEy E x y x Front View

3 Several Cases Linear polarization:  y -  x =0 o or ±180 o n Circular polarization:  y -  x =±90 o & E ox =E oy Elliptical polarization:  y -  x =±90 o & E ox ≠E oy, or  ≠ 0 o or ≠180 o n even if E ox =E oy Unpolarized- natural radiation Cruz-Pol,ECE Dept. UPRM

4 Linear polarization  in time domain Cruz-Pol,ECE Dept. UPRM x y EyEy E x Front View y x Back View:

5 Circular polarization Both components have same amplitude E ox =E oy,  =  y -  x = -90 o = Right circular polarized (RCP)  =+90 o = LCP Cruz-Pol,ECE Dept. UPRM

6 Elliptical polarization X and Y components have different amplitudes E ox ≠E oy, and  = ±90 o Or  ≠ ±90 o and E ox =E oy, Cruz-Pol,ECE Dept. UPRM

7 Parámetros de la elipse Cruz-Pol,ECE Dept. UPRM y x E yo o b a

8 Polarization Loss Factor PLF Cruz-Pol,ECE Dept. UPRM

9 Poincaré Sphere Plots any possible state of polarization Cruz-Pol,ECE Dept. UPRM

10


Download ppt "Polarization: Why do we care?? Antenna applications – – Antenna can only TX or RX a polarization it is designed to support. Straight wires, square waveguides,"

Similar presentations


Ads by Google