The open-ended waveguide transducer with wire in circular window

Development of microwave scanning near-field microscopy and introscopy in millimeter-wave range is the problem of keen interest due to perspectives of applications in novel technologies. The detection of defects in dielectric slabs and measurements of parameters of materials are urgent tasks of the applied physics. A method of employing waveguide-type microscopic aperture probe has been proposed. It has been shown that the microscopic aperture has allowed one to get high spatial resolution of scanning microscopy for surface topography. Structures consisting with a conducting plate, placed outside a waveguide-fed rectangular aperture were proposed for non-destructive measurements of the dielectric samples. Specifically, λ/4 - resonator and ring microwave one can be used for this purpose as an initial transducer. But the problem is to improve the spatial resolution and sensitivity. The advantage of waveguide structures is excellent shielding effect due to its metallic walls, thus avoiding radiation loss even in the millimeter-wave range. Thus, creation of the sensors in millimeter range on the basis of the waveguide structures is rather perspective. Earlier it was considered many approaches of establishing the various sensors. For example, a radio-frequency evanescent-mode cavity resonator for passive wireless sensor applications has been presented. These papers considered such structures for the various airflow measurements. The purpose of this paper is investigation of a novel structure of an initial transducer on the base of ideas of Zhao et al., 2008 and Zhao et al., 2010.