You are quite right. I thought I read 'broadband' on the Raymarine website but a quick check proved otherwise.
The newer radars from Raymarine, Garmin and Furuno also far better than their older cousins. but the use different technology than the broadband type radars.
I'm not sure what you mean by "No there are no standard for interfacing radars with MFD's". Our older chart plotter displays both charts and radar though in separate windows.
I will try to explain.
In the "old days" we had dedicated units
A radar antenna connected to a radar display
A chart plotter connected to a GPS receiver
Today these will often be one box with one screen and control buttons, this type of units we call Multi Function Displays (MFD)
NMEA 0183 and NMEA 2000 are standards that make it possible to share data between devices from different manufacturers.
I have wind/speed/depth sensors from Raymarine connected to a box that convert sensor data into NMEA 2000 format.
This data can be displayed on both my Furuno MFD and my Raymarine i70 displays and be used by my autpilot from Coursemaster.
Modern radar antennas have all the "logic" in the antenna, and the MFD is just an display and control unit.
So if I added another Furuno MFD to my boat I would be able to view radar on both displays.
But if I add a Raymarine MFD it will not be able to show radar pictures from the Furuno radar
But the NMEA standard
does not say anything about radar data, so that is why you must have radar and display from same manufacturer.
We do already have AIS send/recieve via a newer plotter as well.
So many electronic gadgets for an electronic imbecile like me. Sigh.
You didn't say what kind of equipment you already have (make & modell)
Would make it easier to give a good answer