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Physical Length Spec, Grounded Shield (Closed Form): COAXI2

Symbol

Summary

COAXI2 simulates a lossy transmission line with a grounded shield. This model implies that the total loss is proportional to the square root of the evaluation frequency and demands that you input a specified loss at a specified frequency. Characteristic impedance is represented by user-specified input.

Parameters

Name Description Unit Type Default
ID Element ID Text CX1
Z Characteristic impedance   50
L Length Length 0
K Dielectric constant   2.3
A Loss in dB/meter   0.0833
F Frequency loss is specified at Frequency 0.1 GHz

Parameter Details

A and F. These parameters determine the frequency-dependence of the attenuation constant. If F is not equal to zero (0.0), then

(dB/m) where freq is the evaluation frequency. If F is equal to zero, the attenuation is zero at all frequencies. Note that attenuation is extrapolated across frequency sweep, so do not set F to an extremely low value.

Implementation Details

Dielectric constant K and computed (see the previous details of parameters A and F) attenuation are used to obtain a complex propagation constant. Entries of Y-matrix of a grounded transmission line system are determined via the characteristic impedance and computed complex propagation constant that you specify.

The following is a Y-matrix for a grounded transmission line system:

where α+jβ represents the complex propagation constant as derived from the input parameters, K, A and F. Z represents the characteristic impedance of the line and L is the length of the line.

Layout

This element does not have an assigned layout cell. You can assign artwork cells to any element. See “Assigning Artwork Cells to Layout of Schematic Elements” for details.

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