conversion loss in mixer

[gwthmnr]

If I simulate a mixer circuit using HB simulation in ADS my IF output is increasing when compared to my RF instead of decreasing.
what will the reason behind this??
can any1 help me:--(

 

[Baranidaran]

Mixer will produce both sum and difference of applied input signals. You might get the sum output; to get difference output, use suitable filter

 

[gwthmnr]

I mean my IF power is increasing instead of decreasing.
i.e., IF power = RF power + Conversion loss

my conversion loss is -5.7dB...

 

[Baranidaran]

The conversion loss of an RF mixer is a measure of its efficiency. The RF mixer conversion loss is defined as the ratio of the level of one of the output sidebands to the level of the RF input. This ratio is expressed in dB.

As only half of the input power can ever exist in one of the sidebands, this means that the best conversion loss that can ever exist in a diode mixer is 3dB. However other losses are also present in the mixer. These occur as a result of diode insertion loss, spurious signal generation, transformer core loss, etc. As would be expected, the conversion loss of the RF mixer will deteriorate towards the edges of the specified frequency band, mainly as a result of the transformer losses increasing.

The conversion loss is also found to be a function of the carrier drive level, increasing particularly if the LO drive level is not correct. However it is also found that the conversion loss can be improved by providing a short circuit impedance at the output port for the undesired sideband. It is also necessary to provide external decoupling for the IF and RF ports of a single balanced mixer in order to achieve the specified conversion loss.