Solenoid antenna of radio engineering system of metal identification

Abstract

The detection of metallic objects hidden in a dielectric medium is carried out with the aid of metal detectors constructed on a vortical current principle. Then detected metal is identified. For identification of metals, as usual, chemical, optoelectric, X-ray methods are used. But detection and identification can be done simultaneously using the graphic-digital image method. In such devices a coaxial solenoid antenna of the frame type is used. But it has low sensitivity, uneven depth sensitivity and a significant parasitic connection between the receiving and transmitting antennas. From such shortcomings, a free antenna is a DD type system, but it does not allow the use of a graphical-digital signal processing method. Therefore, a new design of the antenna system is proposed, which allows us to take advantage of the considered signal processing method and DD antennas. It is characterized in that one of the antennas, for example, a transmitter, consists of two parts that are symmetrically placed relative to the second and creates two active radiation zones, such as a coaxial antenna, but are similar to the radiation zones of the DD type antenna.