Patent Publication Number: US-6710750-B2

Title: Microwave sensor antenna

Description:
BACKGROUND OF THE INVENTION 
     The subject of the invention is the microwave sensor antenna for instantaneous position measurement of movable element, especially in turbo-machine. 
     The microwave antenna in the shape of waveguide of rectangular or circular intersection is known from the elaboration titled: “Microwave antenna theory and design”, Massachusetts Institute of Technology, McGraw-Hill Book Company, Inc. 1949. 
     BRIEF SUMMARY OF THE INVENTION 
     The subject of the invention is, that the antenna centric duct in the form of long cylinder has a coaxial channel of circular intersection at one end, and a coaxial screwed tongue at the other end. On one third of cylinder length there is a lateral screwed port. With the help of the tongue, the cylinder is coaxialy connected to the cylindrical housing inside its cylindrical hollow in which there is an antenna sleeve with necking, placed on the axis of the hollow. Inside the lateral screwed port of the cylinder, there is a short support of the waveguide. In the free end of the support, there is a transverse cut. In the transverse cut of short support of the waveguide, one end of the waveguide in the shape of rod of circular intersection is located. Its second end is located in transverse cut of long waveguide support, located in lateral screwed port of the cylindrical housing, at its opposite end. The waveguide is placed inside the cylindrical longitudinal channel, made in parallel to longitudinal axis of the antenna, and connected to the cylindrical hollow inside the housing. On the housing axis, there is the cut of rectangular intersection to a depth of one third of the housing length, located in parallel to cylindrical longitudinal channel and perpendicular to the axis of waveguide long and short support. At the end of the cut inside the housing, there is transversal cylindrical hollow with the diameter equal to dual value of cut width and the axis placed on outside wall face of this cut. Inside the cylindrical wall along the waveguide short support, there is a coaxial hole with a fine thread. Inside the hole there is an antenna adjusting screw cooperating with a back nut. On the outside wall face, from cylindrical hollow side, there is a clamp nut with the escapement, and from the opposite side, the housing has an antenna back nut on its outside face. Free space of the coaxial cylindrical hollow, cylindrical longitudinal channel, and rectangular intersection cut is filled with dielectric body. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The FIGURE is a sectional view of the present invention. 
    
    
     DETAILED DESCRIPTION 
     The longitudinal section of the invention subject is shown on the picture. Antenna centric duct  1  in the form of long cylinder has a coaxial channel of circular intersection  2  at one end, and a coaxial screwed tongue  3  at the other end. On one third of cylinder length  1  there is a lateral screwed port  4 . With the help of the tongue  3 , the cylinder is coaxialy connected to the cylindrical housing  5  inside its cylindrical hollow  6  in which there is antenna sleeve  7  with necking, placed on the axis of the hollow  6 . Inside the lateral screwed port  4  of the cylinder  1 , there is a short support  8  of the waveguide. In the free end of the support, there is a transverse cut  9 . In the transverse cut  9  of short support  8  of the waveguide, one end of the waveguide  10  in the shape of rod of circular intersection is located. Its second end is located in transverse cut  11  of long waveguide support  12 , located in lateral screwed port  13  of the cylindrical housing  5 , at its opposite end. The waveguide  10  is placed inside the cylindrical longitudinal channel  14 , made in parallel to longitudinal axis of the housing  5 , and connected to the cylindrical hollow  6  inside the housing. On the housing  5  axis, there is the cut of rectangular intersection  15  to a depth of one third of the housing  5  length, located in parallel to cylindrical longitudinal channel  14  and perpendicular to the axis of waveguide long  12  and short  8  support. At the end of the cut  15  inside the housing  5 , there is transversal cylindrical hollow  16  with the diameter equal to dual value of cut  15  width and the axis placed on outside wall face of this cut. Inside the cylindrical wall  5  along the waveguide short support  8 , there is a coaxial hole  17  with a fine thread. Inside the hole there is an antenna adjusting screw  18  cooperating with a back nut  19 . On the outside wall face of the housing  5 , from coaxial cylindrical hollow  6  side, there is a clamp nut  20  with the escapement, and from the opposite side, the housing has an antenna back nut  21  on its outside face. Free space of the coaxial cylindrical hollow  6 , cylindrical longitudinal channel  14 , and rectangular intersection cut  15  is filled with dielectric body. 
     Operation: After tuning with an antenna adjusting screw  18 , the microwave probing signal is supplied to the input circuit of a standard wave resistance, formed by antenna  1  centric duct and antenna sleeve  7 . Then, the signal goes through the waveguide  10  of a standard wave resistance to the waveguide cavity—antenna radiator in the shape of rectangular intersection cut  15 , ended with transversal cylindrical hollow  16 . The opposite side of the waveguide cavity antenna radiator creates microwave antenna aperture. The microwave probing signal radiates from the aperture around the movable element of a turbo-machine. This signal is the subject to modulation during reflection from movable element of a turbo-machine and it is received in this form by the microwave antenna aperture. After reception, the signal goes to the input circuit via the waveguide  10 . 
     Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.