Confused: Insertion Loss with power combiner same as divider?

[pratiken]

Hi,
I'm measuring a 1:8 power splitter and getting about 10dB of insertion loss at 2.4Ghz with my Anristu VNA. I'm measuring S21 with Port 1 on one of the input ports and Port 2 on the single output with all other ports terminated.

When I flip them, so port 1 is on the output and port 2 is on one of the 8 inputs, I get the same insertion loss.

I'm confused because I thought when used as a power combiner, there should only be the insertion loss of <2dB or so, but when you use it as a power divider, you have the full 9dB+/-<2dB.

Can someone explain what I'm doing or understanding incorrectly?

Thank you so much!!

[rfeecs]

A power splitter (with no ferrites) is a passive reciprocal device.  So S21=S12.

To get minimum insertion loss as a combiner, all 8 inputs signals have to be the same amplitude and phase in order to combine in-phase.

[awallin]

A power splitter (with no ferrites) is a passive reciprocal device.  So S21=S12.

To get minimum insertion loss as a combiner, all 8 inputs signals have to be the same amplitude and phase in order to combine in-phase.

this seems to be what the last paragraph over here is saying also:
https://www.microwaves101.com/encyclopedias/basic-network-theory

[chrisl]

5kHz is a common workinf frequency for inductive proximity switches. Also some electromedical devices.
Further, it seems that it is a often used test frequency for audio gear.

Eh?  Is this a continuation of this thread spilling over to the RF section??  LOL.
https://www.eevblog.com/forum/projects/need-help-with-emc-problem-and-audio/?all

[chrisl]

The 10 dB insertion loss on a 8 port splitter/combiner sounds about right.
If you put two 8 port splitters/combiners back to back in such way that the 8 ports are directly connected to each other via the same length of cables (i.e. barrels) you will see the insertion loss between the 2 common ports will be <4 dB ( <2 dB for each combiler) since all the phase/amplitude on each ports are the same.

[Neomys Sapiens]

5kHz is a common workinf frequency for inductive proximity switches. Also some electromedical devices.
Further, it seems that it is a often used test frequency for audio gear.

Eh?  Is this a continuation of this thread spilling over to the RF section??  LOL.
https://www.eevblog.com/forum/projects/need-help-with-emc-problem-and-audio/?all

Sorry! too many open tabs!