A new class of semiconductor devices is proposed with electrically controlled electrode's area. It is shown that by implementing this basic idea within the commonly available technology one is able to construct the varactors (varicaps) with almost any prescribed C-U characteristic in contrast to severely limited functionality of traditional devices. More importantly, very promising new devices (which we call semiconductor capacitive transformers-SCTs) can be produced using these varactors. In contrast to known semiconductor devices SCTs are able to overcome the fundamental electronic constraint on the maximum power handling capability, which is currently a real stumbling block for any semiconductor device due to final velocity of mobile charge carriers and junction breakdown. SCT-based ultra-high-power frequency transducers and capacitive transformers can be easily fabricated by means of standard planar technology and are expected to replace bulky inductive transformers in high-frequency and microwave integrated circuits. Also described are some 'proof-of-the-concept' experiments performed by the authors. Results obtained are very encouraging. (C) 2004 Elsevier Ltd. All rights reserved.