1. 2012 mid-term examination (110)
Antenna Engineering
Date: April 23, 2012.
Z L − Z0
Z 0 = 50Ω, f = 2.4 [GHz], Γ =
1. Consider a coaxial line with Z L + Z 0 (50)
1)Calculate the reflection coefficient, Γ in terms of the magnitude and phase
when resistors, R = 12 [Ω] and R = 213 [Ω] are attached. (20)
2)Calculate the VSWR (Voltage Standing Wave Ratio) for problem 1). Hint:)
1+ Γ
VSWR =
1 − Γ (10)
3)Calculate the reflection coefficient, Γ in terms of the magnitude and phase
1
when a capacitor, C = 12[pF] is attached. Hint:) Z C = jωC (20)
2. Calculate the following parameters of a Hertzian dipole antenna (very small
dipole antenna) with I = 500 [mA] , ∆z = 0.1 [mm] , f = 2.4 [GHz]. (30)
1)E-field [V/m] and H-field [A/m] at
r = 1 [km] , θ = 90 , φ = 90  . (20) Hint:)
far-field condition
2)Consider that a propagation constant is the same as that in free-space.
Calculate the phase at the end of dipole when the center phase is 0. (10)
2π
Hint:) φ = βz , β = k = λ , fλ ≈ 3 ×10 [m / s ]
8
3. One of the frequency bands for the LTE (Long-Term Evolution) is designated
from 2110 [MHz] to 2170. (20)
1)Center frequency or modulation frequency (10)

2. 2)Bandwidth (10)