rf mixer design

Does anybody have idea on design broadband mixer? need to convert a fixed RF input to a variable IF output from 10MHz to 2 GHz. Thanks!

The eassiest way would be to use a widely available mmic based device. Try Hittite, Nec, maacom, alpha. All the major rf companies do wideband down-conversion mixers. Do you want to downconvert from 2Ghz to 10Mhz? If so your immage band will be 20Mhz off your wanted signal, you will not be able to do it. You will have to use a superhet topology.

Need more info

Bagster

Hi,

how is the fixed rf input ? (level & freq.)


Syzzler

Try minicircuits.

No

Hi Bagster and guys,

Thanks for your reply.
The device is not a problem for me, what I really concern is how to furthest reduce harmonics and intermodulation products, since the IF ouput will be from 10MHz to 2GHz, the frequency covers twenty decuple order, so it's impossible to use a simple filter, I need at least -50dBc at IF, better to reach -60dBc. a lot of products at -35 to -45dBc, I tried both passive abd active double-balanced devices. RF input is -10dBm on 2.5GHz.

Thanks!

You could use a swept filter, it would depend on your bandwidth, but a varactor tuned filter that is controlled by the LO frequency culd be swep in order to produce a high cutoff of the unwanted signals.

Bagster

Out of interest, what is the application?
Have you thought of a high side LO? this may be better. Look at a domestic satellite tuner. These have the same problems, there may be some mmics available.

Bagster

IMHO, it's not available to build a simple tracking filter since the single down to 10MHz, except you build a very complicated filter system with a lot of separate bands and different topology, if the single is over 1GHz, the thing will become easy, we can simply use a YIG tuning fiter.

It's for providing a single for DVB-C/S test. Yes, LO is 2.501 to 4.5 GHz.

There is a mixer at Peregrine, the PE4140. It can be tuned to meet all these requirements.

Range is very broad. IF output from 10MHz to 2 GHz.

Do they exist these commercially? If someone did them and sells them now.

Of course they exist. Check out the bluecell line from minicircuits. Very impressive mixers at a low price.