PXI 5611

[Longgg]

Hi,

     I have a set of RFSG with PXI 5611 as the RF signal generator. What types of antenna should I choose for the port of "RF out" at pxi 5611? Should I provide DC power for it? Do I have an option to control the DC output at RF out port of PXI 5611?

Thanks

[Jim_S]

Hello,

After reading your post, it seems like you are using our PXIe-5673. As for you questions, I have divided these up below:

1.) What types of antenna should I choose for the port of "RF out" at PXI-5611?

Since the output impedance of the PXI-5611 is 50ohms, the antenna should have an input impedance of 50ohms. As for the rest of the characteristics of the antenna, you will need to decide the structure, size, etc based upon the frequency you are generating.

2.) Should I provide DC Power for it?

I don't see any reason to provide DC Power to the antenna or the PXI-5611. I think I might be able to answer this questions in more detail if you could expand upon your application.

3.) Do I have an option to control the DC output at RF out port of PXI-5611?

Since the PXIe-5673 (which contains the PXI-5611, PXIe-545x, and PXIe-5650/1/2), the output power frequencies don't go down to DC. Are you seeing large DC output power? Is this needed for your application?

If you could provide more information on your application, I think we would be able to look into this further.

[Longgg]

Hi Jim,

      Thank you for your explanation. I have a system for wireless communication with TX and RX. As for the RX, I need to provide external DC power to the antenna. How about the TX? I have the PXIe 5673 as my TX and would like to buy an antenna for the TX. Should I buy the passive or active antenna for PXI 5611? 

Thanks,

Long

[Jim_S]

Hello Long,

For deciding on an active or passive antenna, we need to know the transmit power need for the wireless communication to work properly. Looking at the specifications of the PXIe-5673 on page 21, the maximum output power is Noise Floor (-152dBm/Hz) to 10dBm. What is the maximum output power need for transmitting your signal?

If you need more power, we have a RF amplifier, PXI-5691 8GHz Programmable Amplifer, that can output up to 24dBm. Will this be enough output power to transmit your signal? If it is, a passive antenna can then be used for your applicaiton.

Even though the PXI-5691 provides a lot of flexibility, it might not be the best option for your application if you just need a fixed gain. For this case a active antenna would be a better option. Again, like I said above, it will be imperative to ensure that the impedances are matched. Looking at the VSWR specs for the PXIe-5673 on page 22, it states how much reflections you can have due to impedance mismatch.

I hope this helps you with selecting a passive or active antenna.