Series Resistance with Ansoft Maxwell SV for coax

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Discussion Overview

The discussion revolves around modeling an RG58 coax cable using Ansoft Maxwell SV to determine its series impedance, series resistance, and AC resistance. Participants are exploring the appropriate geometric modeling and solver selection within the software, as well as relevant calculations related to coaxial cables.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant seeks assistance in building a geometric model of RG58 coax cable in Ansoft Maxwell SV to solve for series impedance per unit length.
  • Another participant provides a formula for calculating the characteristic impedance of air-cored coax cable, noting that it does not depend on length but is a property of the cable.
  • A participant clarifies that their main issue lies in using Ansoft Maxwell SV to model the series resistance and AC resistance, indicating a lack of tutorials for the student version of the software.
  • A later post outlines a homework statement that involves determining series resistance, conductance, capacitance, inductance, and AC resistance of the coaxial cable, mentioning that relevant values were obtained from the RG58 spec sheet.
  • The same participant describes their geometric model consisting of concentric circles representing the core, dielectric, and shield of the coax cable, and notes success in finding conductance, inductance, and capacitance using specific solvers.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the best approach for modeling the coax cable in Ansoft Maxwell SV, as there are differing focuses on the software's capabilities and the calculations involved.

Contextual Notes

Some limitations include the lack of comprehensive tutorials for the student version of Ansoft Maxwell SV and the need for clarity on the correct geometry and solver selection for accurate modeling.

nirvan25
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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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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.
 
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.
 
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).
 

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