Series Resistance with Ansoft Maxwell SV for coax

In summary: My problem is in solving for the series resistance. The ANSOFT MAXWELL SV documentation says to solve for it using the Laplace equation, but I am not sure how to do that. I have tried different solvers, but all of them give me different results.I have attached my ANSOFT MAXWELL SV model and the Laplace equation used to solve for the series resistance. In summary, the software is useful for calculating the series resistance of a coax cable, but it is not clear how to do it using the Laplace equation.
  • #1
nirvan25
3
0
Hello, can anyone assist me in building a geometric model of an RG58 coax cable with Ansoft Maxwell SV using the appropriate solver to solve for the series impedance of the cable per unit lenght. The Ansoft Help files available do not cover this.
 
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  • #2
I don't know that modeling program, but if you would like to calculate the characteristic impedance of coax, the following might be useful:

This is for air-cored coax cable :
Z = 138 log ( D / d )

where Z is the characteristic impedance
log is the log to the base 10
D is the inside diameter of the outer conductor
d is the outside diameter of the inner conductor.

D and d must be in the same units as each other.
....eg if D / d = 5 then Z = 96 ohms

The characteristic impedance does not depend on length but is a property of the cable.
 
  • #3
Thanks for the help, but my problem is really using ANSOFT MAXWELL SV to build a model to solve the series resistance of the coax and the ac resistance of the coax. The software version I am using is the student version(SV) and ansoft has not published much tutorials on using their software. I think the problem is confined to selecting the correct geometry and using the right solver, but of which I am not sure.
 
  • #4
Modelling a coax cable with ansoft maxwell sv

Homework Statement


Use Ansoft Maxwell SV to determine the series resistance, conductance, capacitance, inductance and Ac resistance of a coaxial cable by building a simple geometric model and simulating it with different solvers. The cable is RG58.


Homework Equations


All the relevant values used for the software were obtained from the RG58 spec sheet.


The Attempt at a Solution


I have found the conductance, inductance and capacitance using the electrostatic and magnetostatic solvers. My geometry consists of 3 concentric circles, a core ( tinned copper - 0.37" diameter), a dielelectric(foam polyethylene of 0.114" diameter) and the shield or braid( tinned copper diameter - 3.32mm).
 

What is Series Resistance and why is it important in coaxial cables?

Series Resistance is the resistance present in a coaxial cable that affects the flow of current through the cable. It is important because it can cause signal attenuation and affect the overall performance of the cable.

How can Ansoft Maxwell SV be used to calculate Series Resistance in coaxial cables?

Ansoft Maxwell SV is a simulation software that uses electromagnetic field analysis to calculate the Series Resistance in coaxial cables. It takes into account the cable's material properties, dimensions, and operating frequency to accurately calculate the resistance.

What are the factors that contribute to Series Resistance in coaxial cables?

The main factors contributing to Series Resistance in coaxial cables are the resistivity of the cable's material, the dimensions of the cable, and the skin depth of the cable at the operating frequency.

How does Series Resistance impact the overall performance of coaxial cables?

Series Resistance can cause signal attenuation, which means that the signal strength decreases as it travels through the cable. This can lead to degraded performance and affect the quality of the transmitted signal.

Can Series Resistance be reduced in coaxial cables?

Yes, Series Resistance can be reduced by using materials with lower resistivity, increasing the cable's diameter, or using materials with higher skin depth at the operating frequency. Proper cable design and installation techniques can also help minimize Series Resistance.

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