Abstract: A transducer suitable for generating signals in the terahertz region has a resonant cavity (4) with apertures (6) aligned with cold cathode source (2) being a field emitter array. The resonant cavity (4) consists of an inner cylindrical region (8) and an outer toroid region (9) that includes a slot antenna (11). To achieve signal generation in the terahertz region, the cavity (4) is fabricated using an etched polymeric material.

Abstract: A waveguide structure is fabricated by patterning active elements on a semiconductor wafer (21). The upper surface of the wafer (21) and the active elements are then coated by a dissolvable positive resist polymer. The polymer is etched using conventional techniques to produce a former for the structure of die waveguide channel and subsequently the polymer former is coated (26) and electroformed (27) using a suitable metallic material. Finally, the polymer former is dissolved leaving an open channel (25) the boundaries of which are defined by the electroformed stucture. The waveguide structure has the advantage that die active elements are integral with the waveguide structure and lie in a common fabrication plane which means that if the depth of the waveguide varies the active elements remain in the same plane. The waveguide structure is particularly suited for use at terahertz frequencies.