D.A. Usanov - Dr.Sc. (Phys.-Math.), Professor, Head of the Department "Solid State Physics", Saratov State University named after N.G. Chernyshevskii. E mail: UsanovDA@info.sgu.ru
S.A. Nikitov - Corresponding Member RAS, Dr.Sc. (Phys.-Math.), Professor, Deputy Director, Institute of Radio-engineering and Electronics of RAS named after V.A. Kotelnikov. E-mail: nikitov@cplire.ru
A.V. Skripal - Dr.Sc. (Phys.-Math.), Professor, Department "Solid State Physics", Saratov State University named after N.G. Chernyshevsky. E-mail: skripala_v@info.sgu.ru
A.P. Frolov - Researcher, Department "Solid State Physics", Saratov State University named after N.G. Chernyshevsky. E-mail: tanto_85@mail.ru

The possibility to create waveguide structures with forbidden and allowed transmission bands, based on the aperture and frame communication elements placed on its both sides has been experimentally demonstrated. The heterogeneity of the "pin with gap" type was introduced into the tested device to create the resonance feature as a window of transparency (window of closing) in the forbidden (allowed) band. The n-i"p-i"n-structure was placed into the gap between the pin and the frame element to enable electrical operation of the tested microwave semiconductor device characteristics was introduced. The dynamic range of the transmittance control by n-i"p-i"n-structure reached 66 dB. Experimental amplitude-frequency characteristics of the reflection coefficient near the transmission peak in forbidden band and the transmission coefficient near the closing peak in allowed band of tested microwave devices for different values of current flowing through the n-i"p-i"n-structure are presented. The microwave generator based on waveguide short (channel cross-section 23 × 10 mm2) was experimentally investigated. The Gunn diode of 3A703 type as an active element of the generator was placed in the gap of pin holder. The frequency and power of the microwave generator were ~ 9.3 GHz and 5 mW, respectively. The waveguide device in the form of two frame elements connected through the hole in the aperture and containing a semiconductor n-i"p-i"n-structure, placed into the gap between the pin and the frame element, was attached to the output of the microwave generator. The the dynamic range of the microwave Gunn diode generator output signal adjustment reached 18.3 dB under changing the current flowing through the n-i"p-i"n-structure from 0 to 193 mA.