How to Achieve over 1 Gbps with PTP820 product?

It looks like you might be using in-band management.

Check out this discussion here: http://community.cambiumnetworks.com/t5/Licensed-Microwave/PTP-820-in-band-management/m-p/64804

and here: http://community.cambiumnetworks.com/t5/Licensed-Microwave/How-do-I-enable-PTP-820-in-band-management/m-p/42096

Please look at the attachment as well, and pay attention to the very last page.

I hope this helps!

Dave