Activities to develop
Each student in the group has to answer the following questions using academic references to support the research: FIRST STEP
1. What is the practical implications associated to a line with only reactive components or
only resistive components? R// The main consequence that must be taken into account, is that a line that contains only resistive elements, gets to heat up a lot, so it could deteriorate the insulating enamel that covers the cable, so a larger cable should be used.
2. In a practical transmission system. What is a good value for the reflection coefficient and
the VSWR? Explain. R// A good value would be 1, since the ROE can be understood as an indicator of the signal reflected back to the radio transmitter frequency, always taking the value 1 in the denominator. And the lesser of this index, the better!
Therefore, a radio frequency system with SWR 1.4: 1 is better than one with 1.5: 1! And another one with 1: 1 ROE would have a perfect impedance adaptation. In other words, it occurs only in theory.
Finally, the ROE in a radio frequency system can be measured by special devices. One of them, and well known, is the main site. With the "Distance-To-Fault" mode you can identify the location of problems in a damaged d amaged system.
3. What occurs with the voltage and current in a line with the following conditions: line
terminated in its characteristic impedance, line terminated in a short and line terminated in an open?
4. What is the voltage reflection coefficient and what is an ideal value for a transmission
system? R// The voltage reflection coefficient is the one that represents the proportionality or ratio between voltage and current along the transmission line, with two components, a direct wave that travels from the generator to the load and another that travels from the charge to the generator, and it is represented:
V(x) = V + e−yX V − eyX I(x) = I+ e−yX I− eyX vo ltage and current waves? 5. What is the effect of Lossy line on voltage R// When the transmission line introduces losses, it ceases to have an ideal character and it is necessary to extend the previous circuit equivalent by adding two new elements: a resistance series R, which characterizes the ohmic losses per unit length generated by the finite conductivity of the conductors, and that is measured in Ω / m, and a parallel conductance G, with dimensions of S / m (or Ω-1m-1), Ω-1m-1), to represent the losses that occur in the dielectric material by a non-zero non -zero equivalent conductivity.
6. In the Smith Chart identify a =∝, a = 0, two resistive loads and two complex loads.
You have to assume the characteristic impedance.
SECOND STEP FIFTH POINT
A load = 35 35 60Ω is connected to a transmission line with = 75Ω. The line is = 0.45. Find the input impedance and at least two line lengths where the input impedance is real. Use the Smith Chart to Solve the exercise. Una carga Z_L = 35- j60Ω j60Ω está conectada a una línea de transmisión con Z_0 = 75Ω.La 75Ω. La línea es l = 0.45λ 0.45λ . Encuentre la impedancia de entrada y al menos dos longitudes de línea donde la impedancia de entrada es real. Ahora Aho ra se utiliza la tabla de Smith para resolver el ejercicio.
=
= , ,
Depositamos el valor anterior en la carta de Smith, trazamos una línea que inicie en 1,0 y pase por
= , , Al prolongar la línea recta hasta que corte el circuito periférico, podemos leer el origen de Zn, que en este caso es: L =0,166 ɻ =0,166 ɻ l
