Patent Publication Number: US-11398666-B2

Title: Planar antenna clamp system

Description:
FEDERALLY-SPONSORED RESEARCH AND DEVELOPMENT 
     The United States Government has ownership rights in this invention. Licensing and technical inquiries may be directed to the Office of Research and Technical Applications, Naval Information Warfare Center Pacific, Code 72120, San Diego, Calif., 92152; voice (619) 553-5118; ssc_pac_t2@navy.mil. Reference Navy Case Number 111504. 
    
    
     BACKGROUND OF THE INVENTION 
       FIG. 1  is a top-view illustration of an example of prior art planar antenna  10  that is built on a printed circuit board  12 . As is typical with prior art planar antennas, the planar antenna  10  shown in  FIG. 1  is soldered directly to a connector  14 . Other times the connector  14  is soldered directly to a transmission line from the antenna  10 . This is done to enable the antenna  10  to be connected to a transmitter or a receiver, such as the communication device  16  shown in  FIG. 1 . Although this is an effective setup, some disadvantages exist. For example, if higher quality and more expensive connectors are used, these connectors can cost more than the planar antennas themselves and if they are soldered onto the planar antennas, the connectors cannot be easily reused. Soldering the connector directly to the planar antenna could damage the antenna if it is made of a material (e.g., paper and plastic) that is sensitive to the heat involved with soldering. Further, it is not easy to quickly and easily swap out planar antennas in some applications. There is a need for an improved method of connecting a planar antenna to a communication device. 
     SUMMARY 
     Disclosed herein is a planar antenna clamp system comprising: 
     a base, a connector, a clamp arm, a matching circuit, and a clamp. The base has a top surface. The connector is mounted to the base and configured to provide an interface to a communication device. The clamp arm has top and bottom surfaces and proximal and distal ends. The proximal end of the clamp arm is mounted to the base such that, when in an open configuration, an air gap exists between the top surface of the base and the bottom surface of the clamp arm at a distal end of the clamp arm. The clamp arm and the base are oriented with respect to one another such that conductors of a planar antenna may be positioned in the air gap when in the open configuration. The matching circuit is disposed on the top surface of the base and electrically connected to the connector. The clamp is configured to compress the conductors of the planar antenna between the top surface of the base and the bottom surface of the clamp arm such that the conductors of the planar antenna are operatively coupled with the matching circuit, when in a closed configuration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Throughout the several views, like elements are referenced using like references. The elements in the figures are not drawn to scale and some dimensions are exaggerated for clarity. 
         FIG. 1  is an illustration of a prior art version of a planar antenna with a soldered connector. 
         FIG. 2  is an expanded view illustration of an embodiment of a planar antenna clamp system. 
         FIGS. 3A and 3B  are respectively top and perspective-view illustrations of an embodiment of a planar antenna clamp system in a closed configuration. 
         FIGS. 4A and 4B  are respectively top and perspective-view illustrations of an embodiment of a planar antenna clamp system in an open configuration. 
         FIG. 5  is a top-view illustration of an embodiment of a planar antenna clamp system. 
         FIGS. 6A and 6B  are perspective, top-view illustrations of an embodiment of a planar antenna clamp system. 
         FIGS. 7A and 7B  are perspective-view illustrations of an embodiment of a planar antenna clamp system in open and closed configurations respectively. 
         FIGS. 8A and 8B  are side-view illustrations of an embodiment of a planar antenna clamp system in open and closed configurations respectively. 
         FIGS. 9A and 9B  are respectively perspective and side-view illustrations of an embodiment of a planar antenna clamp system. 
         FIGS. 10A and 10B  are respectively top and side-view illustrations of an embodiment of the planar antenna clamp system. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The disclosed system below may be described generally, as well as in terms of specific examples and/or specific embodiments. For instances where references are made to detailed examples and/or embodiments, it should be appreciated that any of the underlying principles described are not to be limited to a single embodiment, but may be expanded for use with any of the other methods and systems described herein as will be understood by one of ordinary skill in the art unless otherwise stated specifically. 
       FIG. 2  is an expanded-view of an embodiment of a planar antenna clamp system  100  that comprises, consists of, or consists essentially of a base  120 , a connector  140 , a clamp arm  160 , a matching circuit  180 , and a clamp  200 . The planar antenna clamp system  100  may be used to quickly connect a planar antenna to the matching circuit  180  and the connector  140  so as to provide an interface to a communication device (such as shown in  FIGS. 1 and 5 ) such as a transmitter, receiver, or a transceiver. The planar antenna clamp system  100  enables planar antennas, even fragile ones such as those made of porous material, plastic, or even paper, to be connected to a communication device (such as the radio  16  depicted in  FIG. 1 ) without the need for soldering. The base  120  has a top surface  220  and a bottom surface  240 . The connector  140  is mounted to the base  120 . The clamp arm  160  has a top surface  260 , a bottom surface  280 , a proximal end  300 , and a distal end  320 . The matching circuit  180  is disposed on the top surface  220  of the base  120  and is electrically connected to the connector  140 . In some embodiments, the matching circuit  180  may be mounted on a separate substrate which is sandwiched between the top surface  220  of the base  120  and the bottom surface  280  of the clamp arm  160 . 
       FIGS. 3A and 3B  are respectively partial, top-view and partial, perspective-view illustrations of an embodiment of the planar antenna clamp system  100  in a closed configuration. The clamp  200  is configured to compress a planar antenna  340  between the matching circuit  180 , which is disposed on the top surface  220  of the base  120 , and the bottom surface  280  of the clamp arm  160  such that conductors (such as are shown in FIG.  4 A) of the planar antenna  340  are operatively coupled with the matching circuit  180 , when in the closed configuration. The planar antenna  340  is not shown in  FIG. 3B  for ease of illustration. 
       FIGS. 4A and 4B  are respectively partial, top-view and partial, perspective-view illustrations of an embodiment of the planar antenna clamp system  100  in an open configuration. The proximal end  300  of the clamp arm  160  is mounted to the base  120  such that, when in the open configuration, an air gap  360  exists between the matching circuit  180  and the bottom surface  280  of the clamp arm  160  at the distal end  320  of the clamp arm  160 . The clamp arm  160  and the base  120  are oriented with respect to one another such that conductors  380  of the planar antenna  340  may be positioned in the air gap  360  when in the open configuration. The planar antenna  340  is not shown in  FIG. 4B  for ease of illustration. 
       FIG. 5  is a top-view illustration of an example planar antenna  340  connected to the planar antenna clamp system  100 , which, in turn, is connected to a communication device  16 . The planar antenna clamp system  100  may be used with any type of planar antenna. Suitable examples of planar antennas include, but are not limited to, patch antennas, slot antennas, ring antennas, spiral antennas, bow-tie antennas, tapered-slot antennas, Yagi slot antennas, quasi-Yagi antennas, log-periodic dipole array antennas, and leaky wave antennas. Planar antennas have been used in many applications because they can be low-cost, low-profile, and can be mass produced. The planar antenna clamp system  100  transitions the antenna  340 &#39;s impedance to a desired impedance, which in most cases is 50 ohms. However, it is to be understood that that planar antenna clamp system  100  may be configured to transition the antenna  340 &#39;s impedance to any other desired impedance. The planar antenna clamp system  100  allows for different antennas  340  to be quickly swapped depending on the target signal of interest. In some embodiments, the planar antenna clamp system  100  may be the only means of supporting the antenna  340 . 
     The base  120  may be any desired size and shape that allows the conductors  380  of the planar antenna  340  to be pressed between the bottom surface  280  of the clamp arm  160  and the matching circuit  180 . In some embodiments, the base  120  may be made of a low loss material, non-conductive material such as plastics (ABS, POM, Nylon, Polypropylene, Polycarbonate, PLA), composites (fiberglass, carbon fiber, Kevlar), glass, and ceramics. In some embodiments, the base  120  comprises a nonconductive substrate, to which the matching circuit  180  is mounted and a supporting base section, which may be conductive such as, but not limited to, stainless steel and aluminum. Suitable examples of material from which the base  120  may be constructed include, but are not limited to, metal, plastic (e.g., ABS, Delrin, Rexolite®, nylon, etc.), glass, and printed circuit board material (FR4, Rodgers, Teflon, etc.). 
     In the embodiment of the planar antenna clamp system  100  shown in  FIGS. 4A and 4B , the base  120  is shaped so as to provide alignment guides  390  configured to align the conductors  380  of the planar antenna  340  with the matching circuit  180  as the planar antenna  340  is inserted into the air gap  360  such that there is operative overlap between the planar antenna conductors  380  and the matching circuit  180 . The surface area of the electrical contact between the planar antenna  340  and matching circuit  180  can accommodate thin (i.e., &lt;1 millimeter) and porous materials. 
     The connector  140  may be any connector used to attach an antenna to a radio frequency (RF) communication device (such as the communication device  16  shown in FIG.  5 ). Suitable examples of the connector  140  include, but are not limited to, Type N connectors, UHF (PL259) connectors, (Threaded Neill-Concelman) TNC connectors, Reverse Polarity TNC (RPTNC) connectors, Bayonet Neill-Concelman (BNC) connectors, SubMiniature version A (SMA) connectors, and Reverse Polarity SMA (RPSMA) connectors. The connector  140  may be electrically coupled to the matching circuit in any suitable manner, as is known in the art. 
     The clamp arm  160  may be attached to the base  120  in any way that allows for the distal end  320  of the clamp arm  160  and the base  120  to form the air gap  360  when the planar antenna clamp system  100  is in the open configuration. For example, the proximal end  300  of the clamp art  160  may be rotatably or hingedly coupled to the base. In another example, the proximal end  300  of the clamp arm  160  is secured to the base  120  so as to form a cantilevered beam having elastic deflection properties that cause the distal end  320  of the clamp arm  160  to move away from the base  120  when in the open configuration. In one embodiment, a spring force (either external or internal to the clamp arm  160 ) causes the clamp arm  160  to move away from the base  120  when in the open configuration. Suitable examples of material from which the clamp arm  160  may be constructed include, but are not limited to, ABS, POM/Delrin, polylactic acid (PLA), Rexolite®, nylon, glass, and printed circuit board material (FR4, Rodgers, Teflon, etc.). It is preferable for the clamp arm  160  to be non-conductive. 
     The matching circuit  180  is designed to match the impedance of the planar antenna  340  to the impedance of the communications device  16 . In one embodiment of the planar antenna clamp system  100 , the matching circuit  180  is designed to match the impedance of the planar antenna  340  to a 50 ohm embodiment of the communication device  16 . The matching circuit  180  is a matching network that can be designed with transmission lines or lumped elements. The matching circuit  180  may comprise passive or active electronics, or a combination of both, such as low noise amplifiers, filters, etc. The matching circuit  180  allows for antennas to be designed at impedances other than 50 ohms. By relaxing this constraint, different antennas can be designed and optimized for performance, transmission line spacing, and signal loss. The matching circuit  180  may be covered with a protective, non-conductive coating such that no metal-to-metal contact is used to couple the matching circuit  180  to the conductors  380  of the planar antenna  340 . For example, the matching circuit  180  may be protected by a layer of dielectric material and operatively coupled to the planar antenna  340 , when in the closed configuration, via inductive or capacitive coupling. In the embodiment of the planar antenna system  100  shown in  FIG. 2 , the matching circuit  180  is a passive, tapered transmission line, or more specifically a tapered co-planar waveguide transmission line. Other suitable examples of the matching circuit  180  include, but are not limited to, a two-wire line, a microstrip line, and a parallel-plate line. 
     The clamp  200  may be any device configured to press the conductors  380  of the planar antenna  340  against the matching circuit  180  between the clamp arm  160  and the base  120 . Suitable examples of the clamp  200  include, but are not limited to, screws, springs, buttons, snaps, and snap tapes.  FIGS. 2-5  show embodiments of the planar antenna clamp system  100  made of acrylic sheet, copper tape, and 3D printer material where the clamp  200  is a mechanical cam-lever locking arm comprising a lever  400  and a cam  410 . The lever  400  has a distal end  420  and a proximal end  430 . The proximal end  430  of the lever  400 , in this embodiment, is rotatably coupled to the base  120 . The cam  410  is mounted to the proximal end  430  of the lever  400  such that when the lever  400  is rotated with respect to the base into a first position (such as is shown in  FIG. 3B ) the cam  410  is disposed to apply force to the clamp arm  160  that causes the clamp arm  160  to move into, and remain in, the closed configuration. Rotating the lever  400  with respect to the base  120  into a second position (such as is shown in  FIG. 4B ) allows the clamp arm  160  to move into the open configuration. 
       FIGS. 6A, 6B, 7A, 7B, 8A, and 8B  are illustrations of an embodiment of the planar antenna clamp system  100  where the clamp  200  is a magnetic clamp comprising a clamp bar  440  a first magnet set  450  and a second magnet set  460 .  FIGS. 6A and 6B  are respectively top and bottom perspective views of this magnetic clamp embodiment of the planar antenna clamp system  100 .  FIGS. 7A and 7B  are respectively open and closed perspective views of this magnetic clamp embodiment of the planar antenna clamp system  100 .  FIGS. 8A and 8B  are respectively open and closed side view illustrations of the magnetic clamp embodiment of the planar antenna clamp system  100 . The clamp bar  440  is slidably disposed on the top surface  260  of the clamp arm  160  such that the clamp bar  440  can slide between a first position (shown in  FIGS. 6A, 7B, and 8B ) and a second position (shown in  FIGS. 7A and 8A ). The first position of the clamp bar  440  corresponds with the closed configuration and the second position of the clamp bar  440  corresponds with the open configuration of the planar antenna clamp system  100 . 
     While the magnetic clamp embodiment of the planar antenna clamp system  100  shown in  FIGS. 6A-8B  has a first set of magnets  450  and a second set of magnets  460 , it is to be understood that many different magnet clamp embodiments are possible with any number of desired magnets. In the illustrated example magnetic clamp embodiment the first magnet set  450  is mounted to the clamp bar  440 . The second magnet set  460  is disposed in recesses on the bottom surface  240  of the base  120 . In the first position, the first and second magnet sets  450  and  460  are vertically aligned such that there is attractive force between them thereby causing the clamp arm  160  to move into, and remain in, the closed configuration. When the clamp bar  440  is in the second position, the first and second magnet sets  450  and  460  are offset from each other so as to cause repulsive force therebetween thereby allowing the clamp arm to move into the open configuration. In some embodiments, the magnet sets  450  and  460  are positioned with respect to each other such that when the clamp bar  440  is in the second position, the repulsive force between the first and second magnet sets  450  and  460  lifts the clamp arm  160  into the open configuration. For example, in the illustration of the planar clamp antenna system  100  shown in  FIGS. 7A and 7B , the cross-sections of the clamp arm  160  and a section of the clamp bar  440  are trapezoidal such that the clamp arm  160  fits within, and is held captive in, the clamp bar  440 . This is done such that when the repulsive force between the first and second magnet sets  450  and  460  pushes the clamp bar  440  up, the clamp bar  440  pulls the clamp arm  160  up at the same time. 
     In some embodiments of the planar antenna clamp system  100 , any magnetic or metallic components (other than the matching circuit  180 ) of the planar antenna clamp system  100  (such as magnets, screws, washers, etc.) are positioned vertically at least 1 mm away from the top surface  220  of the base  120  or the transmission line plane. If a metallic component is in the same plane as the transmission line, it needs to be 1 mm away from the gap  470  between a center conductor  480  and ground plane  490  (depicted in  FIG. 2 ). 
       FIGS. 9A and 9B  are respectively perspective and side-view illustrations of an embodiment of the planar antenna clamp system  100  in the open configuration that further comprises a lock feature  490  configured to prevent the planar antenna  340  from sliding with respect to the base  120  when the planar antenna clamp system  100  is in the closed configuration.  FIGS. 10A and 10B  are respectively top and side-view illustrations of the embodiment of the planar antenna clamp system shown in  FIGS. 9A and 9B , but in the closed configuration. In some embodiments of the planar antenna clamp system  100 , heat sensitive components in the matching circuit  180  and/or in the planar antenna  340  can be used in the matching circuit  180  and elsewhere because no soldering needs to be done on the antenna  340  or the planar antenna clamp system  100 . Although, in some embodiments, soldering could be used if desired. The planar antenna clamp system  100  may be used to connect to other RF/microwave components with the appropriate transmission line feed, or the planar antenna clamp system  100  could be used to connect to a transmission line only (without an antenna or other RF component). 
     From the above description of the planar antenna clamp system  100 , it is manifest that various techniques may be used for implementing the concepts of the planar antenna clamp system  100  without departing from the scope of the claims. The described embodiments are to be considered in all respects as illustrative and not restrictive. The method/apparatus disclosed herein may be practiced in the absence of any element that is not specifically claimed and/or disclosed herein. It should also be understood that the planar antenna clamp system  100  is not limited to the particular embodiments described herein, but is capable of many embodiments without departing from the scope of the claims.