@User @User My understanding of the reason for including dummy poly gates at each end of a transistor is to improve the matching of the fingers you care about. As far as I understand, the fabrication process will yield different geometries for the gates at the ends of a device, and as such, you should make sure that the gates at the ends are not gates who's matching you care about, hence the reason for dummies. I've also seen layouts of FETs comprising a large number of fingers which have more than one dummy on each end. I'm not an expert though, please correct me if I'm wrong. If you were wondering why dummies are included on the RF layouts specifically rather than in general then I assume you're aware of some trade off that I'm not? If so please let me know.