Transmitted Power of a waveguide using CST

change port power

Hi everybody
i am analyzing Cylindrical waveguide using CST Microwave studio. I want to calculate Total Power transmitted and Power loss for a cylindrical waveguide using CST but I am not understanding hw can i calculate it? Plz help me.

Thanks

s11 input power loss formula

Ashubhu said:

Hi everybody
i am analyzing Cylindrical waveguide using CST Microwave studio. I want to calculate Total Power transmitted and Power loss for a cylindrical waveguide using CST but I am not understanding hw can i calculate it? Plz help me.

Thanks

Click to expand...

Hi,


I do not know, where is problem exactly, but you have cylindrical waveguide - so you have one port on the one side and second port on the second side - after calculate, you have S21, S11, S12 and S22 (S21=S12 and S11 = S22). This is your transmitted and return loss.

But if you have cylindrical waveguide for your for your frequency (so that mean correct diameter), S21 = 0 dB and S11= - ∞ dB (exactly about -50 - -60 or -100 dB).

Can you give me more specification of your problem ?

cst problem s21

Hi, thanks for your reply
i have considering Cylindrical waveguide exactly. For this, i want the total power transmitted(Pt) and power loss(PL) calculation as you can see in Liao's Book. These i want to calculate using CST. Power transmitted and power loss with modewise is also of the intrest. So you plz help me hw can i calculate using CST. S-parameter we have found but Power transmitted and power loss are different from that.

Thanks

transmitted power loss

The power will be reflected, transmitted and loss.
1-S11*S11 represent the power except reflection loss. If waveguide does no has loss, S21*S21=1-S11*S11. However, practical waveguide has loss, 1-S11*S11-S21*S21 represent transmission loss

change waveguide port power in cst

Kezman said:

The power will be reflected, transmitted and loss.
1-S11*S11 represent the power except reflection loss. If waveguide does no has loss, S21*S21=1-S11*S11. However, practical waveguide has loss, 1-S11*S11-S21*S21 represent transmission loss

Click to expand...

Very-very thanks Kezman, I highly appreciate your suggestion. Really this will help me for solving my problem.
One more thing i wanted to know. S11 and S21(S-parameters) in CST is obtained with mode-wise. So the power Transmitted and power loss will be for the related mode. Wheathe or not, we can obtained the Total Power transmitted and Total Power loss???
One more thing ,Can we change input exciting signal power to any value in CST?

power transmitted in waveguide

The same to it!
You can simulate any mode in CST, but practically, the loss lie on the mode which you inspirit on the input port.

You need not to change power on port, because S-Parameter is the proportion of power in CST. If you want to get loss about the power, you can calculate: Transmitted Power (dBm)=Input Power(dBm)-|S21|(dB). If you want to get loss about Watt, you can Input Power(Watt)-Transmitted Power (Watt)

power formula waveguide

Kezman said:

The same to it!
You can simulate any mode in CST, but practically, the loss lie on the mode which you inspirit on the input port.

You need not to change power on port, because S-Parameter is the proportion of power in CST. If you want to get loss about the power, you can calculate: Transmitted Power (dBm)=Input Power(dBm)-|S21|(dB). If you want to get loss about Watt, you can Input Power(Watt)-Transmitted Power (Watt)

Click to expand...

Thanks Kezman, i am grateful to your kind help..

Re: power formula waveguide

Hi everyone,

I'm trying to find the power being coupled in to different modes at a particular surface/area inside a waveguide using CST. The waveguide itself is being excited by a probe inside of it. And the surface/area to which the amount of power being coupled in to by different modes, could be defined as a waveguide port set across the cross section of the waveguide. But so far, I've been unable to solve this issue.

If any one knows how to solve this, please enlighten me

Thanks in advance