Can a Transistor be Junctionless?

I do not see much of a difference between this and a MESFET. I'll admit that patent protection may be obfuscating the details. But why would they then reference a 1925 design while simultaneously claiming a new transistor.

In a MESFET there is a Schottky junction forming the gate. Here, the device is a MOSFET. There are no junctions from source to drain and no Schottky junction. The use P-type polysilicon on the N-doped device allows one to obtain a desired threshold voltage, butr you could use a metal such as platinum instead.

I suspect that they mean that it does not have a traditional diffused junction, but a metallic & insulator "mechanical" junction. It would be interesting to know how low the heat/resistive losses are for the source-drain path, and how that relationship varies with gate applied voltage.

I think the heat/resistive losses will be the same but it could work at higher temperature.

It has the same heat losses as any transistor, but it works at higher temperature. See the article "High-Temperature Performance of Silicon Junctionless MOSFETs", Chi-Woo Lee, Adrien Borne, Isabelle Ferain, Aryan Afzalian, Ran Yan, Nima Dehdashti, J.P. Colinge, IEEE Transaction on Electron Devices vol.57, no.03, pp.620-625 (2010)