Power supply

Dear Azaro,

Azaro said:

I have designed an impedance matching circuit to adapt an antenna.

I would like to test the entire schematic by inputting different powers through the input port, such as -10dBm or -20dBm,

Most impedance matching circuits are passive in nature, especially those designed to match an antenna's impedance. In this case, why are you interested in its  behavior with input power? In other words, the components used are all passive elements and hence will not produce any harmonic frequencies. Therefore, a linear analysis, which is independent of applied input power, will provide an accurate estimate of your circuit's performance.

In this case, an S-parameter analysis will provide a view of your S11 and S12. This will allow for plotting of each parameter.

You may still want to use caution if you are using any S-parameter input files due to the many subtleties associated with their use.

Shawn

Hello Shawn,

Thank you very much for your response. Let me clarify the situation. I am trying to simulate the behavior of a directional coupler. I am attaching an image with the basic scheme of what I want to do.

I would like to know what power I will have in the coupled and isolated channels by introducing a certain power at the input of the coupler, for example 24dBm. Later, I would like to sweep from 500MHz to 3GHz with that power at the input. The problem is that I cannot find any port (element) to supply this power and later perform a sweep to be able to see it on a graph.

Can you help me?

Thank you very much for your attention!

A.O.

Dear Azaro,

Thank you for your added information! Both the graphic and your objective are very helpful as I think I understand your question now,

Azaro said:

I would like to know what power I will have in the coupled and isolated channels by introducing a certain power at the input of the coupler, for example 24dBm.

I have a thought that I will pass by you. You did not indicate specifically what you consider the "input", but I am assuming you intend to suggest the input is the antenna. However, since the directional coupler is passive and the antenna can be represented by its impedance, the system is bidirectional. Hence, suppose instead you consider the "input" to be the 50 ohm source you have labeled "Pi" as I highlight in Figure 1.

Azaro said:

The problem is that I cannot find any port (element) to supply this power and later perform a sweep to be able to see it on a graph.

Hence, you might define the source Pi and its 50 ohm impedance as the input port to supply the power. The power of this source can be defined as it is a signal port. You can then examine the power at the coupled and isolated ports.

Is this a possibility?

Shawn

Figure 1

Thank you very much for the quick response! What I have for now is the following:

Where I consider the input to be port 1, but as you have rightly said it is bidirectional. The problem is that I don't know how to define at the input (port 1) that I want to supply a power of for example 24dBm, or any other value.

I understand that when simulating the S11, S12, S13, etc. at the input, 0dB is supplied. As in the following image:

How can I change that value?

Thank you very much for your attention again!

Dear Azaro,

Thank you for your added information!

Azaro said:

I understand that when simulating the S11, S12, S13, etc. at the input, 0dB is supplied. As in the following image:

Azaro said:

How can I change that value?

I must be missing something obvious, but the S-parameter analysis linearizes the circuit about its DC operating point and is by its nature a linear analysis.  Hence, the response of the outputs will be linearly proportional to the input. Hence, your output parameters, such as S11, S12, and S13 will be independent of the input power.

Your passive network is not non-linear and hence its responses wlll not show any non-linearity and hence its response will be independent of the power to its input.

Therefore, it does not make sense to me as to why you want to increase the power (i.e., sweep) the input power. I think I mentioned this in my initial response to your post.

Am I overlooking something?

Shawn

Perhaps Azaro can confirm, but I think you're using Microwave Office based on the schematic you shared earlier in the thread? It really helps when posting questions if you actually say which tools you're using - this was posted in the Custom IC Design forum, so I moved it into the RF Design forum (which covers RFIC issues in Virtuoso/ADE/Spectre but also covers Microwave Office too).

Andrew

Perhaps Azaro can confirm, but I think you're using Microwave Office based on the schematic you shared earlier in the thread? It really helps when posting questions if you actually say which tools you're using - this was posted in the Custom IC Design forum, so I moved it into the RF Design forum (which covers RFIC issues in Virtuoso/ADE/Spectre but also covers Microwave Office too).

Andrew