Passive complex bandpass filter using lossy and loose coupling transformers

In this paper, we propose a passive complex bandpass filter using lossy and loose coupling transformers. The proposed complex filter has desired and undesired passbands. The undesired passband can be excluded by using transformers with suitable Q and coupling coefficient values. It is shown that the simulation circuit exhibits complex bandpass characteristics (9-11 rad/s) and an image rejection ratio of 61.7 dB.