| Author |
Message |
ajhsu
Joined: 04 Apr 2004
Posts: 224
Helped: 3
|
 18 Dec 2004 4:02 Loss on narrow microstrip line & on wide microstrip line |
|
|
|
|
Assume 2 microstrip line are both 50 Ohm impedance but the first trace is
narrow and the second trace is wide by different PCB stack.
Which one get bigger loss ??
The narrow trace get bigger loss or they get the same loss??
(Both of them are 50 Ohm impedance)
Thank you.
|
|
| Back to top |
|
 |
summersonic
Joined: 17 Dec 2004
Posts: 10
|
18 Dec 2004 5:19 Re: Loss on narrow microstrip line & on wide microstrip |
|
|
|
|
generally speaking,the narrow one 'lossing is low!
you can see a structure of microstrip to waveguide, wideband insert loss is about 1 dB but narrow band could be more than less than 0.3 dB!
|
|
| Back to top |
|
|
sergio mariotti
Joined: 22 Dec 2003
Posts: 467
Helped: 42
Location: Italy
|
18 Dec 2004 10:25 Re: Loss on narrow microstrip line & on wide microstrip |
|
|
|
|
Loss of µstrip depend by the conductor loss and dielectric loss.
In most cases the conductor loss dominate the dielectric loss.
As the current is more distribuited as the metal loss, of course, decrease.
So larger is the W as the dissipative loss is low.
... but... as large is W as large is the fringing capacitance, so... pay attention to the mismatch due to the end effects. 
|
|
| Back to top |
|
|
masadi
Joined: 02 Dec 2004
Posts: 74
Helped: 8
|
18 Dec 2004 12:30 Loss on narrow microstrip line & on wide microstrip line |
|
|
|
|
dielectric loss depends on substrat conductivity, so it will be different for different substrate.
discontinuity of microstrip line such as bending, open end also make loss.
Added after 6 seconds:
dielectric loss depends on substrat conductivity, so it will be different for different substrate.
discontinuity of microstrip line such as bending, open end also make loss.
|
|
| Back to top |
|
|
Google
AdSense
|
18 Dec 2004 12:30 Ads |
|
|
|
|
|
|
| Back to top |
|
|
g579
Joined: 01 Jan 1970
Posts: 476
Helped: 14
Location: Somewhere
|
19 Dec 2004 13:38 Re: Loss on narrow microstrip line & on wide microstrip |
|
|
|
|
AWR's free Txline program
hxxp://www.mwoffice.com/products/txline.html
may show you actual losses for different substrates and conductors. Perhaps experiencing some examples may show you the right directions.
|
|
| Back to top |
|
|
House_Cat
Joined: 21 Feb 2002
Posts: 1507
Helped: 307
Location: USA
|
20 Dec 2004 8:51 Re: Loss on narrow microstrip line & on wide microstrip |
|
|
|
|
Both DC resistance per unit length, and the skin effect loss per unit length, will be greater in the narrow trace. Those two factors will cause the signal loss in the narrow trace to be greater than those in the wide trace at all frequencies.
The dielectric loss will be approximately equal in the two at any given frequency, assuming the same dielectric is present above and below both traces.
|
|
| Back to top |
|
|
