Free impedance calculator software comes to the aid of circuit designers

April 13, 2011 //By Jean-Pierre Joosting
Rogers Corporation is offering the latest version of its simple but powerful Microwave Impedance Calculator, MWI-2010.

Available for free download from the company’s web site at www.rogerscorp.com/acm/index.aspx, this handy program provides fast and easy calculations of key transmission-line parameters based on Rogers’ extensive lines of high frequency circuit materials.

Written by John Coonrod, Market Development Engineer for Rogers Advanced Circuit Materials Division, the software uses proven closed-form equations to determine the impedance and loss of a wide range of different circuit types, including microstrip and stripline designs.

Users can download and run the easy-to-use executable file on any Windows-compatible personal computer. Analysis for a desired circuit type and material begins by simply selecting a transmission-line technology, such as conventional microstrip, from a menu of choices as well as a high frequency circuit-board material from a wide choice of Rogers’ materials.

The program displays key parameters for each material selected, including dielectric constant, dissipation factor (loss), coefficient of dielectric constant, and thermal conductivity. Passing the cursor over a particular product name, such as RT/duroid® 6202, will reveal additional properties about the highlighted material. The user can select a standard thickness for a material, or override the standard values by manually entering a custom thickness. Users can also select from standard values of copper thickness, copper surface roughness, and conductivity, or customize these parameters as well.

The MWI-2010 program allows users to synthesize or analyze a number of transmission-line parameters, such as conductor width and conductor spacing for target impedance, using models for a variety of transmission-line technologies, such as coplanar waveguide, stripline, and microstrip, including an improved edge-coupled microstrip model.

The software provides results for a range of operating frequencies, showing data in English or metric equivalents and calculates the temperature rise above ambient temperature for a selected laminate based on an input RF power level. Calculated transmission-line information can be cut and pasted into another program, such as a word processing program, for creating reports or saved in a comma-delimited file format for import into

Design category: