Sorry for the unfocussed question. I am a chemistry student and building one instrument and for this I want to know about the BNC connector. I have read few things on that. But my confusion is why BNC connector cannot carry more than 4 GHz signal. In text book it is written that BNC is for 0-4 GHz.
To carry an Electromagnetic wave signal at a specific frequency range requires the "media" to be as "smooth" as possible,as not to disturb the prorogation of the signal from one point to the other .
We do this by using "wave guides",most of them are coaxial cables.
The connectors are used at the ends to physically connect the source and destination.
This will insert a disturbance in the wave guide(transmission line) in the form of impedance mismatch because of the way the connector is build,the dielectric used,it's size,the quality of the mechanical connection etc.
These mismatches are defined in many ways, the most common being insertion loss and return loss vs. frequency
The higher the frequency the higher the disturbance.
So, for higher frequencies a better design and build quality is needed..
BNC isn't a good choice for high frequencies,
use N-type(if space and budget allows) or SMA..
For good performance,I personally wouldn't use BNC above 1GHz.
Here is a catalog of K and V types that will reach 65GHz.
For further reading on above 100GHz connectors development look here.
This Wikipedia article says the Passband is typically 0 to 4 GHz. Without a deeper understanding of transmission line theory, the OP might be led to believe that somehow at 4 GHz the BNC connector suddenly stops working. Real world devices almost never suddenly stop working. Degradation in performance may occur rapidly, but almost never "suddenly," as in "now it works, and now it doesn't" behavior.
Without a deeper understanding of transmission line theory, the OP might be led to believe that somehow at 4 GHz the BNC connector suddenly stops working. Real world devices almost never suddenly stop working