I fear that you have entirely failed to grasp the point I was making. It is true that the transmit signal is many orders of magnitude stronger than the receive signal, but one cannot fix that entirely with the circulator, no matter how good it is. Time for circulator and antenna 101!
I typical ferrite circulator has three ports (let's call them A, B and C). Energy put into port A comes out of B, energy into B and out C and in C to out A. You get the idea. Now, as with everything in life, circulators aren't perfect and they have a parameter called 'isolation'. I typical value for a modern circulator is 20dB (or a power factor of 100). This means that if I for example put 100W into port A, then 99W will come out of port B and 1W will go the wrong way and come out of port C (in practice a little bit of the power will be lost internally as heat). Supposing that I connect A to the transmitter, B to the antenna and C to the receiver. In my example I will get 1W flowing into the receiver which could be 100dB (10^10) more than the intended receive signal. Clearly something else needs to be done, but making the circulator better won't help. Why?
Because of reason (b) in my comment - the return loss of the antenna. Antennas also aren't perfect and they have a parameter called return loss. An ideal antenna will take all the power from the transmitter and convert it into electro-magnetic waves propagating away. Real antennas however have imperfections and some of the power from the transmitter goes into the antenna and bounces back out again. A typical value for a good antenna is 20dB. Really good narrow band waveguide antennas (e.g. a decent radar) might manage 30dB, but the antenna on you mobile phone or Wi-Fi base station may well only manage 10dB. So, where does that leave us?
Returning to my example. 100W comes out of the transmitter and 99W goes to the antenna. If it has a 20dB return loss (if we are lucky) then 1W (give or take) will bounce back into circulator port B and nearly all of that will emerge from port C and go into the receiver. So, the receiver is getting 1W due to circulator imperfections and about 1W due to antenna imperfections. We can improve our circulator until the cows come home and the most we will do is reduce the power into the receiver from 2W to 1W which isn't going to save the day.
As I said in my comment, the real cleverness here is not the design of the circulator (which is probably as good as it needs to be), but the amazing performance claimed for the subsequent (and not very well described) canceller.