High frequency microstrip pcb

i need to design microstrip pcb (50Ω char. impedance @ say 1-5GHz) for testing SMD type components.
I use RT duroid 5880 5mil/10mil
someone told me that i have to maintain
track width / dielectric height = 2
for 50 ohm char. impedance
if so the width will be constant, but i need to change the width of track according to the pin of the component without affecting the char. impedance.

Also is there any software tool to do the job for me?

Pls help.....

Hello,

Dielectric constant is about 2.2. To get 50 ohms impedance, width/height ratio must be about 2.9.

Full data you can find on:
https://www.rogerscorp.com/acm/products/10/RT-duroid-5870-5880-5880LZ-High-Frequency-Laminates.aspx
You can also find several application notes and they have/had a transmission line utility.

You should ask yourself, do you want to measure the component on his pad or without the pad? Other question, do you need to do a single port or 2-port measurement?

When you want compensate the effect of the pads, you need de-embedding. I would suggest a search on: VNA, calibration de-embedding. You may add TRL (Transmission – Reflect – Through).

You can use ....Agilent,s ADS Software ... i f u want change the width while maintaining constant 50 impedence, u should use Taper line. In ads u can easily draw it.

Added after 3 minutes:

can u give me stack up of ur PCB Board, So that i can help u...

Added after 9 minutes:

for RT duroid 5880 5mil,
diele. constant will be 2.2, if t= 35um,
then u should maintain w=0.36mm

Thank you WimRFP and rupeshchannawar

i am almost a fresher to microstrip or rf....

yes i want to measure the parameters of component (surface mount amplifiers, mosfets, switches say hmc313, inductors.....).
i need to measure both the input and output reflections of the components and sometimes the insertion loss.

could u pls tell me were can i find more information regarding de-embedding, TRL, Taper line (almost a fresher).

Also how long could the track can be so that i wont loose much of the power (sometimes i have to get 3-4cm tracks length for the connector to be properly fixed), is there a way to compensate long track...

Hello,

I assume you have a VNA. You might read the documentation to learn the basics of the VNA and the calibration principle (for coaxial cables with "load", "open" and "short" terminations for a single port).

For a dual port calibration, you may also need to calibrate for S21/S12. There a various calibration schemes that incorporate de-embedding (=removal of parasitic effects in the test fixture). Maybe your VNA has some features for that. The Internet is a good source, I don't have better sources than you can find on the Internet. You may contact the vendor of the VNA, but maybe he will use this opportunity to sell you something additional.

Regarding the components to be tested, it is a really wide range. You will have measurements that are closely centered in the smith chart, but also very close to the edge of the smith chart (where accuracy becomes less). This is not an easy task.

Regarding the length of the lines. Losses will not be that high and after calibration, the loss and phase shift of your test fixture (that is small PCB with connectors and soldering pads) will be corrected by the VNA (or separate SW package).

Hi....
As u r fresher...first u should learn fundamentals of transmission line....please check this attached document...this will be helpful for u.

thank you guys
i will back after i go through.....