Problem:Single Ended mixer design

Hello...

I am working on project "passive single balanced diode" mixer with 180 degree hybrid. I have used ADS 2008 software for the implementation.

I did analysis with harmonic balance. But strange thing is happening with the results. When optimized for one RF signal power for e.g. 0dBm, it gives required conversion loss -8 dB. But when the input RF power is degraded to -80 dBm, the conversion loss becomes -50 dBm.

Can any one help me in solving this issue..

Thanks.

Could you upload your simulation file to check?

That means you need more power level from the local oscillator.