powers99
Newbie level 1
i have an exam coming up and these are sample questions.....i just wanted help in a few questions mentioned below...
1. Consider a 50 Ω transmission line of half-wavelength (λ/4) long. It is
connected on its left to a 10 V (rms) source with 75 Ω internal
impedance, and connected on its right to an infinite 100 Ω line.
a) Compute the incident power, reflected power, and the power
transmitted into the infinite 100 Ω line.
b) Present methods to maximize the power transmitted into the
infinite 100 Ω line (source cannot be changed).
2. A load impedance of ZL = 40 + j 30 Ω is to be matched to a Z0 = 50 Ω
line by inserting a series connection of a lossless line of characteristic
impedance Z1 and length L. Find
a) Z1 and L.
b) the magnitude of the voltage, |VL|, across the load if the amplitude
of the voltage at the input terminal, |Vin|, of the matched line is 5 V
(rms).
3. Use signal flow graphs to find the power ratios P2/P1 and P3/P1 for a
mismatched three-port network, where ports 2 and 3 are connected to
20 and 75 Ω loads, respectively, the characteristic impedance Z0 of the
lines in the network is 50 Ω, and the scattering matrix of the network is
given by
0 0.6 0
= 0.6 0 j0.8
0 j0.8 0
4. Derive the [Z] and matrices of a 3 dB attenuator matched to
transmission lines of 300 Ω characteristic impedance. Also find the
resistances of the resistors in the circuit.
a) Using a two-port T network,
b) Using a two-port π network.
5. An air filled rectangular cavity resonator has its first three resonant
modes at the frequencies: 5.2, 6.5, and 7.2 GHz. Find the dimensions of
the cavity.
1. Consider a 50 Ω transmission line of half-wavelength (λ/4) long. It is
connected on its left to a 10 V (rms) source with 75 Ω internal
impedance, and connected on its right to an infinite 100 Ω line.
a) Compute the incident power, reflected power, and the power
transmitted into the infinite 100 Ω line.
b) Present methods to maximize the power transmitted into the
infinite 100 Ω line (source cannot be changed).
2. A load impedance of ZL = 40 + j 30 Ω is to be matched to a Z0 = 50 Ω
line by inserting a series connection of a lossless line of characteristic
impedance Z1 and length L. Find
a) Z1 and L.
b) the magnitude of the voltage, |VL|, across the load if the amplitude
of the voltage at the input terminal, |Vin|, of the matched line is 5 V
(rms).
3. Use signal flow graphs to find the power ratios P2/P1 and P3/P1 for a
mismatched three-port network, where ports 2 and 3 are connected to
20 and 75 Ω loads, respectively, the characteristic impedance Z0 of the
lines in the network is 50 Ω, and the scattering matrix of the network is
given by
0 0.6 0
0 j0.8 0
4. Derive the [Z] and
transmission lines of 300 Ω characteristic impedance. Also find the
resistances of the resistors in the circuit.
a) Using a two-port T network,
b) Using a two-port π network.
5. An air filled rectangular cavity resonator has its first three resonant
modes at the frequencies: 5.2, 6.5, and 7.2 GHz. Find the dimensions of
the cavity.