This is how the person worked it out. First the parallel R and Xc can be expressed as admittances, by simply taking the reciprocal of each. Then they are normalised by dividing by 0.02, which is the value at the centre of the chart (it is the Zo of the line, 50 Ohms or 1/50=0.02 Siemens). Plot the normalised admittance, then notice the VSWR, which is the radial distance, and we rotate around the chart at this radius towards the generator for a distance of 0.15 lambda. This point gives the admittance at the generator, and we travel across the chart to the opposite point to obtain the normalised impedance at the generator. Multiply R and X by 50 to obtain the required values.maearnie said:
Thank you very much! i was wondering why they multiplied 50 instead of multiplying it. hahahatech99 said:
A Smith Chart is a graphical tool used in electrical engineering to help analyze and design radio frequency circuits. It is a polar plot of the complex reflection coefficient, which is a measure of how much of an incident wave is reflected at a certain point in a transmission line.
To find the input impedance for an antenna problem using a Smith Chart, you would first plot the load impedance on the chart. Then, you would draw a line from the center of the chart through the load impedance point, representing the transmission line. Next, you would find the point on the line where it intersects with the constant resistance circle, which represents the characteristic impedance of the transmission line. This intersection point gives the input impedance of the antenna.
The characteristic impedance of a transmission line is the ratio of voltage to current at any point along the line. It is represented as a resistance value and is dependent on the physical properties of the transmission line, such as its length, diameter, and material.
The Smith Chart is useful for solving antenna problems because it allows for quick and accurate visualization of complex impedance values. With its polar plot, it is easy to see the magnitude and phase of the reflection coefficient, which is crucial in designing and analyzing antenna systems.
Yes, the Smith Chart can be used for other types of circuits besides antenna problems. It can be used to analyze and design any circuit with transmission lines, such as amplifiers, filters, and matching networks. It is also useful for impedance matching and adjusting circuit parameters to achieve desired performance.
