[en] The necessity of new acceleration methods with very high gradients for TeV linear colliders was recognised about ten years ago. During the last years it became apparent that new methods will need a very long development time, interesting physics can be done in the sub-TeV range and the main problem is not the generation of very high gradients but of an adequate luminosity. Today research and development work is concentrated on final focus design, beam dynamics, beam generation and radio-frequency acceleration. Some recent developments in new accelerator structures are overviewed, with special emphasis on parameter constraints and on RF power generation. (R.P.) 17 refs.; 4 figs