# Mutual Conductance formula/computation in transmission line

• niceeng
In summary, the conversation discusses the topic of computing the coupling effects or crosstalk in a circuit and how to calculate mutual conductance, denoted as g12. It is suggested to look into coupled lines and recommended books on the subject are David Pozar's "RF and Microwave Coupled-Line Circuits" and "RF and Microwave Coupled-Line Circuits" by Mongia, Bahi, and Bhartia. It is noted that coupled-lines is a more advanced and difficult topic compared to transmission lines.

#### niceeng

Hi all,
I am trying to compute the coupling effects or crosstalk in the circuit attached.
In MTL (multiconductor transmission line) model of two wire or three wire lines for main lines, how to calculate or simple equation of mutual conductance?

which is denoted as g12 in the circuit attached.

Thank you

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Look into coupled lines. This is an advanced topic, I studied it a few years ago and I don't dare to comment until I have a chance to read back the stuff. Only RF book I have that get into this a little is David Pozar, just got into it a little only. Very few book even talk about this topic. The other one you can look at is

RF and Microwave Coupled-Line Circuits by Mongia, Bahi and Bhartia.

Coupled-lines is a giant leap obove transmission lines in difficulty. If you try to do this in matrix, it is a 4-port network and I did wasted 3 days writing out the matrix, all the determinants and all and I fail to get the answer! I double check and triple check my work and still didn't get it. I gave up verifying the formulas.

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## 1. What is mutual conductance in transmission lines?

Mutual conductance is a measure of the ability of two transmission lines to share current. It is a measure of how easily current can flow between the two lines, and is dependent on the physical characteristics of the lines, such as their distance and geometry.

## 2. How is mutual conductance calculated?

Mutual conductance is calculated by taking the ratio of the current flowing between the two lines to the voltage difference between them. This can be expressed as Gm = I/V, where Gm is the mutual conductance, I is the current, and V is the voltage difference.

## 3. What factors affect the mutual conductance of transmission lines?

The mutual conductance of transmission lines is affected by factors such as the distance between the lines, the material and geometry of the lines, and the frequency of the signal being transmitted. Higher frequencies and closer distances typically result in higher mutual conductance.

## 4. Why is mutual conductance important in transmission lines?

Mutual conductance is important in transmission lines because it determines how efficiently current can be shared between the lines. This can affect the overall performance and reliability of the transmission system.

## 5. How can mutual conductance be improved in transmission lines?

Mutual conductance can be improved in transmission lines by reducing the distance between the lines, using materials with higher conductivity, and optimizing the geometry of the lines. Additionally, proper maintenance and monitoring of the lines can also help to improve mutual conductance.