LNA ( S parameters ) - RF Cafe Forums

The original RF Cafe Forums were shut down in late 2012 due to maintenance issues - primarily having to spend time purging garbage posts from the board. At some point I might start the RF Cafe Forums again if the phpBB software gets better at filtering spam.

Below are the old forum threads, including responses to the original posts.

-- Amateur Radio
-- Anecdotes, Gripes & Humor
-- Antennas
-- CAE, CAD, & Software
-- Circuits & Components
-- Employment & Interviews

-- Miscellany
-- Swap Shop
-- Systems
-- Test & Measurement
-- Webmaster

amit
Post subject: LNA ( S parameters ) Posted: Tue Jul 26, 2005 5:03 am
hi to all ,
can anyone help me , please ?
I want to know that how can we fabricate FET with desired S parameters ? let me clear my question ....
suppose that I design LNA with S parameters taking from datasheet and now when I make its' layout I must make FET with exactly same S parameters as I took from datasheet. Please help me ....
you can mail me at :-

amitgopal1@rediffmail.com
Thanks
--amit

Top

IR
Post subject: Posted: Tue Jul 26, 2005 6:25 am

Site Admin

Joined: Mon Jun 27, 2005 2:02 pm
Posts: 373
Location: Germany
Hi Amit,

You have to take the S-Parameters from the data sheet. Usually manufacturers will provide S2P file for the device. Before you make the layout, you have to make simulation, and enter the properties of the transmission lines, via holes for ground and any other physical connection into the simulation. Another important thing is to enter the proerties of the substrate you intend to use into the simulation (Its dielectric constant,
Tan delta, width etc).The simulation will give you overall S-Parameters of the design including total gain and return losses. When you fabriacate your circuit you take from this simulation the dimensions of transmion lines and via holes for grounds.

_________________
Best regards,

- IR

Posted 11/12/2012