SG61-addict
Junior Member level 1
Hello,
I am using a minicircuits SCN-3-13+ power splitter/combiner (3 ways, 0°).
Before the splitter, I have a SMA connector, some LF filtering and a LNA. This input block is connected the the SUM port of the splitter.
Each output port of the splitter, is connected to a SAW filter and LNA, giving 3 amplified and filtered signals in 3 different frequency bands.
Simulating the whole design would give me approx. +23dB of gain for all 3 channels.
In the real life, I have a huge unbalance :
- 847MHz channel : +20dB
- 868MHz channel : +13dB
- 897MHz channel : +30dB
If I remove the splitter, measuring S-params of all pre and post block give me the expected values.
My conclusion is that the pre/post blocks composed of filtering and LNA are ok but the splitter don't works as planned. I am not a RF expert and not sure this device is compatible for this usage (split 3 low-power signals from an antenna).
I tried to removed the 3 required isolation resistors. Things are a little bit different but still wrong:
- 847MHz channel : +23dB
- 868MHz channel : +16dB
- 897MHz channel : +31dB
Which type of resistance am I supposed to use for the RF application? Current design is using thick-film resistor.
Any suggestion will help
Thank you
I am using a minicircuits SCN-3-13+ power splitter/combiner (3 ways, 0°).
Before the splitter, I have a SMA connector, some LF filtering and a LNA. This input block is connected the the SUM port of the splitter.
Each output port of the splitter, is connected to a SAW filter and LNA, giving 3 amplified and filtered signals in 3 different frequency bands.
Simulating the whole design would give me approx. +23dB of gain for all 3 channels.
In the real life, I have a huge unbalance :
- 847MHz channel : +20dB
- 868MHz channel : +13dB
- 897MHz channel : +30dB
If I remove the splitter, measuring S-params of all pre and post block give me the expected values.
My conclusion is that the pre/post blocks composed of filtering and LNA are ok but the splitter don't works as planned. I am not a RF expert and not sure this device is compatible for this usage (split 3 low-power signals from an antenna).
I tried to removed the 3 required isolation resistors. Things are a little bit different but still wrong:
- 847MHz channel : +23dB
- 868MHz channel : +16dB
- 897MHz channel : +31dB
Which type of resistance am I supposed to use for the RF application? Current design is using thick-film resistor.
Any suggestion will help
Thank you