Post subject: A question of LNA Posted: Thu Mar 30, 2006
Joined: Thu Mar 30, 2006 9:20 am
Hello ,I'm a student and know a little ADS .I'm designing
the LNA.When I have mathed input and output impedance using the L and
C,I can design the PCB .But the appliances should't link directly to
each other .there are shuold be the transmission line between them .How
should I decide the transmission line width and length .How do I measure
The influence of the ransmission line .Should the input and output impedanc
Post subject: Posted:
Thu Mar 30, 2006 5:37 pm
Joined: Mon Jun
27, 2005 2:02 pm
When designing a matching circuit you should take into consideration
the transmission lines that connect between the matching components.
In general, these transmission lines should have an impedance of 50
ohm. You can calculate the width of the line by using LINECalc (A tool
of ADS), or just by using a formula (Depednding on the type of transmission
line you use - Co-Planar, µstrip etc). Series transmission lines (50
ohm) will add delay (phase angle), you will see it on the smith chart.
The impedances will be changed of course, but you can tune the values
of the components to compensate for that. Also take into consideration
that the components have tolerance. Finally see that the matching circuit
provides the required matching all over the required BW.
is your operating frequency and BW??