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S. Štaras, R. Martavičius, J. Skudutis,V. Urbanavičius, V. DaškevičiusSimulation and Application of Super-Wide-BandSlow-Wave StructuresSummaryIn 1864, James Clerk Maxwell predicted that electric and magnetic fieldscan propagate in the form of electromagnetic waves. Experiments performed in1885–87 by physicist Heinrich Rudolf Hertz confirmed existence of radio waves.H. R. Hertz developed equipment to produce, radiate, and detect microwaves andobserved the reflection of microwave energy from solids [1]. In 1922, MarcheseGuglielmo Marconi proposed to use short waves for radio detection of objects[1]. In 1934, the first an experimental radar station was developed that led toBritish Home Chain air defense system [1].Needs for radar equipment, expecially in the period of World War II, stimulateddevelopment of microwave technology. Powerful generators and amplifierswere necessary for radars. Scientists and engineers successfully solved problems.Albert Hull invented magnetron in 1920. Brothers Russell and Sigurd Varian developedklystron in 1936. Andrew V Haeff proposed the idea of traveling-wavedevices in 1933. In 1942–43, Rudolf Kompfner developed a traveling-wave tube.Later R. Kompfner and John Pierce refined it at Bell Labs.Interaction of electromagnetic oscillations and electrons of electron beam isused in microwave electrovacuum devices. Traveling-wave devices are based oninteraction of traveling electromagnetic wave and the beam. The velocity of thetraveling-wave must be matched with velocity of electrons. Velocity of electronsis less than velocity of electromagnetic waves in the free space. Thus, retardedwaves are necessary in traveling-wave devices. Slow-wave structures are usedfor retardation of electromagnetic waves.Researchers developed many types of slow-wave devices [3]. Because ofdependence of properties of active microwave devices on properties of usedslow-wave, many efforts were made for development of theory, experimentalinvestigations and improvement of slow-wave devices. Results of investigationsare presented in [4, 5], and many other monographs and papers.