Antenna Design

Lab 06 - Antenna Polarization Match

I. Simulation (70 points)

Dipole dimensions:

Feeding: Center-fed with a discrete port with source impeance of 50 W

Design frequency: f ₀ = (1000 + PIN/1000) MHz

실습조교 PIN = 0000

Dipole end-to-end length: L = 0.40 λ

Dipole diameter: d = L/15

Dipole feed gap at the dipole center: g = d

Dipole material: PEC

Frequency range: 0.5f₀ to 1.5f₀

1. Antenna polarization match (perfectly matched case)

Use Dipole #1 and Dipole #2 with dimensions as above.

Dipole #1 arm: Direction = y, dipole center at z = 0 and x = 0

Dipole #2 arm: Direction = y, dipole center at z = 1 λ and x = 0

1) Plot the antenan structure.

2) Plot |S11|, |S21|_Case1 in dB

3) Find |S21| at f₀.

2. Antenna polarization match (mismatched case)

Use Dipole #1 and Dipole #2 with dimensions as above.

Dipole #1 arm: Direction = y, dipole center at z = 0 and x = 0

Dipole #2 arm: Direction = from +y axis, rotate the dipole toward +x axis by 70°, dipole center at z = 1 λ and x = 0

1) Plot the antenan structure.

2) Plot |S11|, |S21|_Case2 in dB

3) Find |S21| at f₀.

3. Calculate the polarization matching efficiency e_p (dB) of Case 2 given by

e_p (dB) = |S21|(dB)_Case2 − |S21|(dB)_Case1 at f₀.

4. Compare 3 with the theory.

|S21| (q ) = |cosq | |S21| (q = 0) (in natural unit)

|S21| (q )(dB) = 20log₁₀(|cosq |) + |S21| (q = 0)(dB) (in dB)