If the AD5934 is needed, there are most likely other better chips to use because that one is 5 years old and it looks like it uses SPI. I2C is called the Inter Integrated Circuit Communications Bus. You might want to take a brief look here:
https://www.electro-tech-online.com/custompdfs/2012/08/an168.pdf
What was talked about before is that you needed a USB to I2C converter to talk to the AD5933. I2C is a bus, so it can support more than one instrument, but evaluation kits make all sorts of assumptions. So, you might require two evaluation kits and their USB interface for the freq synthesizer/divider and the network analyizer and that also means two USB isolators.
Now, you could "break" the evaluation kit(s) so it uses just the I2C bus and use a single USB to I2C converter with an isolator.
This was an interesting I2C USB solution:
https://www.i2cchip.com/ and this company,
https://www.diolan.com/ probably had the most comprehensive software interface.
You do have to get an idea of the entire hardware/software interface, at least for now, in an overview fashion.
So, I don;t know if your looking for the smallest, nearly wearable gizmo that doesn't require a PC or something that's wearable; a gizmo that returns a number or two or something that records info to be analyzed by a PC or some quick, dirty and safe contraption that needs a PC. For now, I'm assuming the last one.