Project Help on Transitions

[avins_123]

Hello,

I have simulated a transition from Stripline to Microstripline, I have these doubts. The band is S-Band (3-4GHz). The return loss obtained is -26dB and Insertion Loss obtained is -0.5dB.

How to calculate

1) Power( I/P, O/P and P-P powe) of the transition( They say it is calculated from insertion loss i.e, for -0.5dB, it is 1.23watts, Is this right).

2) Bandwidth of the transition( These are transmission lines and not antennas),
I found that BW definition is fh-fl / fc, i.e, fh=3GHz, fl = 4GHz, fc = 3.5GHz, so that means BW is 28.57%, Is this right ?

3) Why is RT Duroid 5880 the best choice for the substrate ?

4) Hos does εr affect the transition, return and insertion loss ?

5) Why is return loss always negative and more and insertion loss positiive and less ?

6) What does -26dB Return loss and 05dB Insertion loss actually mean ?

Please help, I really want to clarify these doubts.

Regards,
Avinash

 

[kspalla]

1) Power( I/P, O/P and P-P powe) of the transition( They say it is calculated from insertion loss i.e, for -0.5dB, it is 1.23watts, Is this right).

Is it power loss by the transition at some power?
Power handled by the transition depends on how the line width, thickness and via diameter, Cu filling or air filling etc.

2) Bandwidth of the transition( These are transmission lines and not antennas),
I found that BW definition is fh-fl / fc, i.e, fh=3GHz, fl = 4GHz, fc = 3.5GHz, so that means BW is 28.57%, Is this right ?

You are right but fh and fl may not be 3 and 4GHz. check the entire range where RL is meeting the spec. that mean more than 28.57%BW.

3) Why is RT Duroid 5880 the best choice for the substrate ?

There are multiple substrates available.

4) Hos does εr affect the transition, return and insertion loss ?

You should be able to tell by the simulations with sweep

5) Why is return loss always negative and more and insertion loss positiive
and less ?

6) What does -26dB Return loss and 05dB Insertion loss actually mean ?

You need lots of study