skrf.media.mline.MLine

class skrf.media.mline.MLine(frequency=None, z0=None, w=3, h=1.6, t=None, ep_r=4.5, mu_r=1, diel='djordjevicsvensson', rho=1.68e-08, tand=0, rough=1.5e-07, disp='kirschningjansen', f_low=1000.0, f_high=1000000000000.0, f_epr_tand=1000000000.0, *args, **kwargs)

Microstripline class

This class was made from the technical documentation 1 provided by the qucs project 2 . The variables and properties of this class are coincident with their derivations.

In addition, Djordjevic 3 /Svensson 4 wideband debye dielectric model is considered to provide more realistic modelling of broadband microstrip as well as causal time domain response.

• Quasi-static characteristic impedance models:

  • Kirschning and Jansen

  • Hammerstad and Jensen

  • None

• Quasi-static effective dielectric constant models:

  • Kirschning and Jansen

  • Hammerstad and Jensen

  • Yamashita

  • Kobayashi

  • None

• Strip thickness correction model:

  • Hammerstad and Jensen, add a certain amount to W if T > 0.

In the case another model is used for effective dielectric constant, Hammerstad and Jensen method is used for the impedance.

Parameters

• frequency (Frequency object) – frequency band of the media

• z0 (number, array-like, or None) – the port impedance for media. Only needed if its different from the characteristic impedance of the transmission

• w (number, or array-like) – width of conductor, in m.

• h (number, or array-like) – height of substrate between ground plane and conductor, in m.

• t (number, or array-like or None, optional) – conductor thickness, in m. Default is None.

• ep_r (number, or array-like) – relative permittivity of dielectric at frequency f_epr_tand

• mu_r (number, or array-like) – relative permeability of dielectric (assumed frequency invariant)

• diel (str) – dielectric dispersion model: ‘djordjevicsvensson’ or ‘frequencyinvariant’.

• rho (number, or array-like, optional) – resistivity of conductor (None)

• tand (number, or array-like) – dielectric loss factor at frequency f_epr_tand

• rough (number, or array-like) – RMS roughness of conductor in m.

• disp (str) –

  microstripline dispersion model in:

  • ’kirschningjansen’

  • ’hammerstadjensen’

  • ’yamashita’

  • ’kobayashi’

  • None

• f_low (number, or array-like) – lower frequency for wideband Debye Djordjevic/Svensson dielectric model

• f_high (number, or array-like) – higher frequency for wideband Debye Djordjevic/Svensson dielectric model

• f_epr_tand (number, or array-like) – measurement frequency for ep_r and tand of dielectric

References

1

http://qucs.sourceforge.net/docs/technical.pdf

2

http://www.qucs.sourceforge.net/

3

C. Svensson, G.E. Dermer, Time domain modeling of lossy interconnects, IEEE Trans. on Advanced Packaging, May 2001, N2, Vol. 24, pp.191-196.

4

Djordjevic, R.M. Biljic, V.D. Likar-Smiljanic, T.K. Sarkar, Wideband frequency-domain characterization of FR-4 and time-domain causality, IEEE Trans. on EMC, vol. 43, N4, 2001, p. 662-667.

Attributes

G	intermediary parameter.
Z0	Quasistatic characteristic impedance.
Z0_f	Frequency dependent characteristic impedance.
alpha	Real (attenuation) component of gamma.
alpha_conductor	Losses due to conductor resistivity.
alpha_dielectric	Losses due to dielectric.
beta	Imaginary (propagating) component of gamma.
beta_phase	Phase parameter.
delta_w1	Intermediary parameter.
delta_wr	Intermediary parameter.
ep_r_f	Frequency dependent relative permittivity of dielectric.
ep_reff	Quasistatic effective relative permittivity of dielectric, accounting for the filling factor between air and substrate.
ep_reff_f	Frequency dependent effective relative permittivity of dielectric, accounting for microstripline dispersion.
gamma	Propagation constant.
npoints	Number of points of the frequency axis.
tand_f	Frequency dependent dielectric loss tangent.
v_g	Complex group velocity (in m/s).
v_p	Complex phase velocity (in m/s).
z0	Characteristic Impedance.

Methods

__init__
attenuator	Ideal matched attenuator of a given length.
capacitor	Capacitor.
copy	Copy of this Media object.
delay_load	Delayed load.
delay_open	Delayed open transmission line.
delay_short	Delayed Short.
electrical_length	Calculate the complex electrical length for a given distance.
extract_distance	Determines physical distance from a transmission or reflection Network.
get_array_of
impedance_mismatch	Two-port network for an impedance mismatch.
inductor	Inductor.
isolator	Two-port isolator.
line	Transmission line of a given length and impedance.
load	Load of given reflection coefficient.
lossless_mismatch	Lossless, symmetric mismatch defined by its return loss.
match	Perfect matched load (\(\Gamma_0 = 0\)).
mode	Create another mode in this medium.
open	Open (\(\Gamma_0 = 1\)).
plot
random	Complex random network.
resistor	Resistor.
short	Short (\(\Gamma_0 = -1\))
shunt	Shunts a Network.
shunt_capacitor	Shunted capacitor.
shunt_delay_load	Shunted delayed load.
shunt_delay_open	Shunted delayed open.
shunt_delay_short	Shunted delayed short.
shunt_inductor	Shunted inductor.
splitter	Ideal, lossless n-way splitter.
tee	Ideal, lossless tee.
theta_2_d	Convert electrical length to physical distance.
thru	Matched transmission line of length 0.
to_meters	Translate various units of distance into meters.
white_gaussian_polar	Complex zero-mean gaussian white-noise network.
write_csv	write this media’s frequency, gamma, Z0, and z0 to a csv file.