Abstract:
A time domain reflectometry waveguide structure ( 1 ) includes: a control module ( 10 ) for transmitting a sensing signal and receiving a reflection signal fed back from the sensing signal; a waveguide sensor ( 20 ) connected to the control module ( 10 ) and including a first probe ( 21 ) connected to the control module ( 10 ), a curved probe ( 22 ) connected to the first probe ( 21 ) and a second probe ( 23 ) extended from the curved probe ( 22 ); a protective cover ( 30 ) coaxially sheathed on the first probe ( 21 ) and exposing the curved probe ( 22 ), and a sensing signal passing through the protective cover ( 30 ) and the first probe ( 21 ) without interference and transmitted to the curved probe ( 22 ) and the second probe ( 23 ) to obtain the reflection signal; and an insulator ( 40 ) covered onto the waveguide sensor ( 20 ) and the protective cover ( 30 ) to prevent interference, facilitate measurements, and measure environmental parameters of different media.

Description:
FIELD OF THE INVENTION 
       [0001]    The technical field relates to an apparatus for measuring the depth of an object under water, more particularly to a waveguide structure that uses a time domain reflectometry method to measure the depth of an object under water. 
       BACKGROUND OF THE INVENTION 
       [0002]    Time Domain Reflectometry (TDR) is a method using the transmission of electromagnetic waves for monitoring, detection and exploration. A transmission system of the electromagnetic waves uses a waveguide as a signal transmitting and sensing component. The design of the waveguide primarily converts the monitored environmental change parameter into a change of transmission signal (such as a reflection signal) of the waveguide, and to obtain an environmental change parameter from the reflection signal. In practice, the travel time of reflection signals generated in different environmental interfaces of the electromagnetic waves is measured, and then the speed of the electromagnetic waves and the travel time of the reflection signal are measured to locate a discontinuous position of the signal, so as to obtain an environmental change parameter. 
         [0003]    Since a multiple of reflections are produced during the process of monitoring the transmission of electromagnetic waves (such as from air into water), therefore it is difficult to identify the reflection signal of the environmental parameter to be measured. In addition, signals are attenuated by the interference of foreign substances during the process of transmitting the electromagnetic waves. More importantly, when the electromagnetic waves are transmitted from an environment (such as water) with a high dielectric coefficient to an environment (such as soil or sludge) with a low dielectric coefficient, a full reflection occurs, so that an environmental parameter with a low dielectric coefficient cannot be detected or measured. 
         [0004]    In view of the aforementioned problems of the prior art, the discloser of this disclosure based on years of experience in the related industry to conduct extensive researches and experiments, and finally provided a feasible solution to overcome the problems of the prior art. 
       SUMMARY OF THE INVENTION 
       [0005]    It is a primary objective of this disclosure to provide a time domain reflectometry waveguide structure to achieve the effects of preventing the interference of foreign substances, facilitating measurements, and measuring environmental parameters of different media. 
         [0006]    To achieve the aforementioned and other objectives, this disclosure provides a time domain reflectometry waveguide structure comprising a control module, a waveguide sensor, a protective cover and an insulator. The control module is provided for transmitting a sensing signal and receiving a reflection signal fed back from the sensing signal. The waveguide sensor is electrically coupled to control module and includes a first probe coupled to the control module, a curved probe bent and coupled to the first probe, and a second probe extended from the curved probe. The protective cover is coaxially sheathed on the first probe and exposes the curved probe, and the sensing signal is passed through the protective cover and out from the first probe without being interfered, and then transmitted to the curved probe and the second probe to obtain a reflection signal. The insulator is covered onto the waveguide sensor and the protective cover. 
         [0007]    Another objective of this disclosure is to provide a time domain reflectometry waveguide structure comprising a reference probe exposed from the insulator and disposed parallel to an edge of the first probe, and the curve of the reflection signal may be used as a reference for comparison for future related computation. 
         [0008]    Compared with the conventional structure, the time domain reflectometry waveguide structure of this disclosure coaxially sheathes the protective cover onto a portion of the waveguide sensor, such that when the sensing signal passes through the protective cover, the signal is not interfered by external objects, so as to prevent the attenuation of the sensing signal. As a result, the waveguide sensor has a long-distance sensing capability. When the sensing signal is transmitted from an environment (such as water) with a high dielectric coefficient to an environment (such as soil or sludge) with a low dielectric coefficient, a full reflection occurs, so that the waveguide sensor can transmit the sensing signal to an environment with a low dielectric coefficient and generate a reflection signal to compute the material level/height successfully. In addition, this disclosure further comprises a reference probe exposed from the insulator, and the curve of the reflection signal may be used as a reference for comparison to facilitate future related computation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1A  is a cross-sectional view of a time domain reflectometry waveguide structure of this disclosure; 
           [0010]      FIG. 1B  is a curve showing the signal intensity of a reflection signal before the detection made by a time domain reflectometry waveguide structure of this disclosure takes place; 
           [0011]      FIG. 2A  is a first schematic view of using a time domain reflectometry waveguide structure of this disclosure; 
           [0012]      FIG. 2B  is a curve showing the intensity of the reflection signal of  FIG. 2A ; 
           [0013]      FIG. 3A  is a second schematic view of using a time domain reflectometry waveguide structure of this disclosure; 
           [0014]      FIG. 3B  is a curve showing the intensity of the reflection signal of  FIG. 3A ; 
           [0015]      FIG. 4  is a schematic view of a time domain reflectometry waveguide structure in accordance with another embodiment of this disclosure. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0016]    The technical contents of this disclosure will become apparent with the detailed description of preferred embodiments accompanied with the illustration of related drawings as follows. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive. 
         [0017]    With reference to  FIGS. 1A and 1B  for a cross-sectional view of a time domain reflectometry waveguide structure of this disclosure and a curve showing the signal intensity of a reflection signal before the detection made by the time domain reflectometry waveguide structure takes place respectively, this disclosure provides a time domain reflectometry waveguide structure  1  comprising a control module  10 , a waveguide sensor  20 , a protective cover  30  and an insulator  40 . The control module  10  is electrically coupled to the waveguide sensor  20 , and the protective cover  30  is sheathed on a portion of the waveguide sensor  20 , and the insulator  40  covers the waveguide sensor  20  and the protective cover  30 . 
         [0018]    The control module  10  is provided for transmitting a sensing signal and receiving a reflection signal fed back from the sensing signal. In this embodiment, the sensing signal is an electromagnetic wave, and the reflection signal with a signal value is reflected when the sensing signal passes through the transmission interface. Preferably, the control module  10  further comprises a coaxial cable  11 , and the waveguide sensor  20  is electrically coupled to the control module  10  through the coaxial cable  11 . 
         [0019]    The waveguide sensor  20  is electrically coupled to the control module  10 . In addition, the waveguide sensor  20  comprises a first probe  21  coupled to the control module  10 , a curved probe  22  bent and coupled to the first probe  21 , and a second probe  23  extended from the curved probe  22 . In practice, the waveguide sensor  20  is comprised of an integrally formed conductor bar. In this embodiment, the second probe  23  is linearly extended from an end of the curved probe  22 , and the second probe  23  is parallel to the first probe  21 . 
         [0020]    The protective cover  30  is coaxially sheathed on the first probe  21  and exposes the curved probe  22 . In an embodiment of this disclosure, the protective cover  30  comprises an insulating tube  31  and a metal tube  32 , wherein the insulating tube  31  is sheathed and fixed to the first probe  21 , and the metal tube  32  is sheathed on the insulating tube  31 . Preferably, the distance between the second probe  23  and the protective cover  30  is greater than 50 mm. 
         [0021]    Preferably, the insulating tube  31  and the metal tube  32  have the same length. In addition, the metal tube  32  has a through hole  320  with a diameter smaller than the diameter of insulating tube  31  and greater than the diameter of the first probe  21 , and the first probe  21  is passed out from the through hole  320  and coupled to the curved probe  22 . Therefore, the first probe  21  is passed and coupled to the insulating tube  31 , and the insulating tube  31  is plugged into the metal tube  32 . The function of the protective cover  30  will be described in details below. 
         [0022]    Since the protective cover  30  comprises a metal tube  32  capable of insulating signal interferences, therefore the sensing signal will not be interfered by external objects when the sensing signal passes through the protective cover  30 , so as to prevent the attenuation of the sensing signal and allow the waveguide sensor  20  to have a long-distance sensing capability. For example, when the waveguide sensor  20  is transported from an environment (such as water) with a high dielectric coefficient to an environment (such as soil or sludge) with a low dielectric coefficient, a full reflection of the sensing signal between two interfaces or other interferences will not occur since the protective cover  30  is sheathed on the first probe  21 . Therefore, the waveguide sensor  20  can transmit the sensing signal to an environment with a low dielectric coefficient and generate a reflection signal to compute the material level/height. 
         [0023]    In addition, the insulator  40  is covered onto the waveguide sensor  20  and the protective cover  30 . In this embodiment, both ends of the insulator  40  are a proximal end  41  and a remote end  42  respectively, and the proximal end  41  and the remote end  42  are closed ends for preventing external moisture or rain from entering. Further, the remote end  42  keeps a distance from an end surface of the protective cover  30 , and the curved probe  22  is disposed between the end surface of the protective cover  30  and the remote end  42 . In practice, the insulator  40  is made of an engineering plastic such as polytetrafluoroethene (PTFE), polyether ether ketone (PEEK), or polyvinylidene fluoride (PVDF), but not limited to such materials only. 
         [0024]    Preferably, the insulator  40  is a cylinder, and the insulator  40  has a diameter increasing with the diameter of the waveguide sensor  20 . In other words, the diameter of the insulator  40  is directly proportional to the diameters of the first probe  21 , the curved probe  22  and the second probe  23 . When the diameter of the first probe  21 , the curved probe  22 , or the second probe  23  increases, the diameter of the insulator  40  also increases, so that the waveguide sensor  20  has an appropriate impedance value. It is noteworthy that when the insulator  40  is made of a different material, the diameter of the insulator  40  is different. In an embodiment of this disclosure, the waveguide sensor  20  and the insulator  40  have an impedance value approximately equal to 50 ohms, but this disclosure is not limited to this value only. 
         [0025]    With reference to  FIG. 1B  for a curve showing the signal intensity of a reflection signal before the detection made by a time domain reflectometry waveguide structure  1  of this disclosure takes place, a sensing signal of the time domain reflectometry waveguide structure  1  passes through the air, wherein Point a indicates the value of the reflection signal when the sensing signal is transmitted to Point A of  FIG. 1A . 
         [0026]    With reference to  FIGS. 2A and 2B  for a first schematic view of a time domain reflectometry waveguide structure of this disclosure and a curve showing the intensity of a reflection signal of the time domain reflectometry waveguide structure respectively, the time domain reflectometry waveguide structure  1  as shown in  FIG. 2A  is installed in a first medium  2  (which is a liquid such as water) and a second medium  3  (which is an object such as sludge) for detecting the material level/height of the first medium  2  and the second medium  3 . Preferably, the first medium  2  has a dielectric coefficient greater than that of the second medium  3 . 
         [0027]    With reference to  FIG. 2B  for a curve showing the intensity of the reflection signal when the sensing signal of the time domain reflectometry waveguide structure  1  passes through the first medium  2  and the second medium  3 , Point b indicates the value of the reflection signal when the sensing signal is transmitted to Point B of  FIG. 2B . In other words, this disclosure can obtain the material level/height of the second medium  3  through the computation of the travel time at Point B of  FIG. 2B . It is noteworthy that the method of calculating the material level/height by the travel time of the reflection signal is a prior art and not the main point of this disclosure, and thus will not be described in details. 
         [0028]    With reference to  FIGS. 3A and 3B  for a second schematic view of using a time domain reflectometry waveguide structure of this disclosure and a curve showing the intensity of a reflection signal of the time domain reflectometry waveguide structure respectively, the time domain reflectometry waveguide structure  1  is also installed in a first medium  2  (which is a liquid such as water) and a second medium  3  (which is an object such as sludge) for detecting the material level/height of the first medium  2  and the second medium  3 , and the first medium  2  has an dielectric coefficient greater than that of the second medium  3 . 
         [0029]    With reference to  FIG. 3B  for a curve showing the intensity of a fed-back reflection signal when the sensing signal of the time domain reflectometry waveguide structure  1  passes through the first medium  2  and the second medium  3 , Point c refers to the value of the reflection signal when the sensing signal is transmitted to Point C of  FIG. 3B . In other words, this disclosure calculates the travel time of Point C of  FIG. 3B  to obtain the material level/height of the second medium  3 . 
         [0030]    With reference to  FIG. 4  for a time domain reflectometry waveguide structure in accordance with a second embodiment of this disclosure, this embodiment is substantially the same as the previous embodiment, except that the time domain reflectometry waveguide structure  1  of this embodiment further comprises a reference probe  50  in addition to the control module  10 , the waveguide sensor  20 , the protective cover  30  and the insulator  40 . The reference probe  50  is electrically coupled to the control module  10 , and the reference probe  50  is exposed from the insulator  40  and disposed parallel to an edge of the first probe  21 , and the sensing signal is selectively transmitted to the waveguide sensor  20  or the reference probe  50 . 
         [0031]    In  FIG. 4 , when the sensing signal is transmitted to the reference probe  50 , the detected reflection signal may be used for monitoring the material level/height of the first medium  2 . After the sensing signal passes through the reference probe  50 , the curve of the reflection signal may be used as a reference for comparison to facilitate the future related computation. 
         [0032]    While this disclosure has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of this disclosure set forth in the claims.