I would like to use PIN Diodes to actuate the T-R switching of my RF Power Amplifier, however, I am having trouble understanding the proper way to accomplish this. I would rather use a solid state switching method over mechanicals relays to save space, and achieve faster switching.
50mW Input (50Ω)
~30W Output (50Ω}
- 12v Power
This is what I have found as the general go-to, however, since I will be using a transceiver I haven't figured out how to adjust it for my application.
This is a block diagram of what I'm trying to do but I'm not sure how to actually make it work. While the transmitter is on the path needs to go to the PA module, and of course be isolated from the output/antenna to not cause catastrophic oscillations. If I use a shunt and a quarter wavelength transmission line won't this interfere with the operation? Would I maybe have to use two quarter wavelength lines on both sides of the "RX" leg?
However, during RX I need to block the path to the input of the amplifier and connect up straight to the antenna. Should I just use a transistor to turn off the PA bias? If I shunt the output of the PA during RX I believe it would just shunt the antenna as well, wouldn't it?
I think I'm just getting confused as to how to properly implement this system. I've spent plenty of time googling PIN diode switches but can only find a "simple" T/R switch, and not one for use with a PA in between.
If I was using a relay I'd use a DPDT type, and maybe a transistor to turn off PA bias, right? So how do I implement this in terms of PIN Diodes?