Abstract:
A plurality of adapters is disclosed for connecting RF connectors to a printed circuit board. The adapters each include a foot print for receiving the RF connector and a plurality of pins for mounting the connector to a prototyping board. The output signal of the RF connector may be coupled to an controlled impedance transmission line, and each adapter is also configured with a ground plane. The adapters may be configured for use with connectors, such as SMA and BNC connectors. The adapters support easy connection of the RF connector to the prototyping board and minimize the noise associated with the output signal of the RF connector.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 60/109,039, filed Nov. 19, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to adapters for electrical devices, and more particularly, to single in-line (SIP) or dual in-line (DIP) adapters for radio frequency (RF) connectors that may be mounted to a printed circuit board (PCB). 
     Many RF connectors are known including Bayonet Nut Connectors (BNC), end-launch Sub Miniature Series A (SMA) connectors, and “F” connectors. Often, these connectors are used in breadboards and prototype circuits using RF devices. However, when prototyping or breadboarding, a significant amount of time is wasted in mounting and connecting the connectors to the PCB. This is because known PCBs do not have a compatible foot print to receive the RF connector. To mount the connector to the PCB, extra holes may be drilled, copper foil may be added to form a ground plane for low impedance connections, and unwanted ground plane area may be cut away to form transmission paths for surface-mount connectors. Accordingly, mounting the RF connector can be laborious and expensive. 
     Known RF connectors can be used to operate attached devices at high frequency levels. This means that the devices require controlled impedance inputs and outputs that are not easily configured in known PCBs. Certain commercially available SIP and DIP adapters require long traces between the device foot print and the pins of the SIP and DIP. This can create excessive noise in the resulting signal and poor performance from the integrated circuit. 
     Therefore, there is a need for an adapter that can be easily and accurately configured for a variety of RF connectors for breadboarding or prototyping applications, and that is also capable of providing controlled impedance and can substantially eliminate noise. 
     SUMMARY OF THE INVENTION 
     In general, in one aspect, the invention is directed to an adapter for a radio frequency connector that includes a printed circuit board having a plurality of first holes. A first layer may be attached to a first side of the printed circuit board, and may have a plurality of second holes. A second layer may be attached to a second side of the printed circuit board, and may have a plurality of third holes. A plurality of headers may pass partially through the first, second, and third holes. At least one transmission line may be formed on the first or second layer. The at least one transmission line may be in electrical communication with the radio frequency connector and the radio frequency connector may be mounted to at least a portion of the printed circuit board. 
     Implementations of the invention include one or more of the following. The printed circuit board may be formed from polymer, plastic, or resin. The first layer or the second layer may be a ground plane. The plurality of headers may include a plurality of first ends that are inserted in to a breadboard or a prototyping board. The plurality of headers may include a plurality of second ends that are substantially coplanar with the first or second layer. The radio frequency connector may include a connector to attach to a radio frequency device. The radio frequency connector may operate in the gigahertz range. The adapter may be a BNC DIP, a SMA DIP, a single SMA SIP, a single SMA DIP, or a dual SMA SIP adapter. At least one transmission line may be a 50 Ohm controlled impedance transmission line. The at least one transmission line may be connected between a center conductor of the radio frequency connector and selected ones of the plurality of headers. The first and second layers and the printed circuit board may each contain a plurality of openings that are vertically or horizontally aligned with each other. The plurality of openings may define a footprint for the radio frequency connector. The plurality of openings may be used to secure the printed circuit board to the first and second layers. The number of first, second, and third holes may be equal to or greater than the number of the plurality of headers. The radio frequency connector may be a BNC or SMA connector. 
     In another aspect, the invention is directed to an adapter for a radio frequency connector that includes a printed circuit board having a first set of holes. A ground plane may be connected at least partially to the printed circuit board and may include a second set of holes that are aligned with the first set of holes. A first layer having a third set of holes that are aligned with the first and second sets of holes may be positioned proximate the printed circuit board. A plurality of headers may pass partially through the first, second, and third holes and at least one transmission line may be formed on the first layer. The at least one transmission line may be in electrical communication with the radio frequency connector. The radio frequency connector may be mounted to at least a portion of the printed circuit board. 
     Implementations of the invention may include one or more of the following. The radio frequency connector may be a BNC connector. The adapter may be a BNC SIP or a BNC DIP adapter. The printed circuit board, the ground plane, and the first layer may each contain a plurality of openings that define a footprint for the BNC connector. The transmission line may be connected between center conductor of the BNC connector and one of the plurality of headers. The adapter may be connected to a prototyping board or a mother board via the plurality of headers. The transmission line may be a 50 Ohm controlled impedance transmission line. 
     In a further aspect, the invention is directed to an adapter for a radio frequency connector that includes a printed circuit board having a first set of holes. A first layer may be connected at least partially to the printed circuit board, and may include a second set of holes that are aligned with the first set of holes. A ground plane having a third set of holes that are aligned with the first and second sets of holes may be positioned proximate the printed circuit board. A plurality of headers may pass partially through at least some of the first, second, and third holes. At least one transmission line may be formed on the first layer. The at least one transmission line may be in electrical communication with the radio frequency connector, and the radio frequency connector may be mounted to at least a portion of the printed circuit board. 
     Implementations of the invention may include one or more of the following. The radio frequency connector may be a SMA connector. The printed circuit board, the ground plane, and the first layer may be at least partially sandwiched between a plurality of leads of the SMA connector. The at least one transmission line may be connected between a center conductor of the SMA connector and one of the plurality of headers. The adapter may be connected to a prototyping board or a mother board via the plurality of headers. The at least one transmission line may be a 50 Ohm controlled impedance transmission line. The adapter may be a single SMA DIP adapter. 
     In yet a further aspect, the invention is directed to an adapter for at least one radio frequency connector that includes a printed circuit board having a first set of holes. A ground plane may be connected at least partially to the printed circuit board, and may include a second set of holes that are aligned with the first set of holes. A first layer having a third set of holes that are aligned with the first and second sets of holes may be formed proximate the printed circuit board. A plurality of headers may pass partially through at least some of the first, second, and third holes. At least one transmission line may be formed on the first layer. The at least one transmission line may be in electrical communication with the at least one radio frequency connector, and the at least one radio frequency connector may be mounted to at least a portion of the printed circuit board. 
     Implementations of the invention include one or more of the following. The at least one radio frequency connector may be a SMA connector. The adapter may be a dual SMA SIP or a single SMA SIP adapter. The adapter may be connected to a prototyping board or a mother board via the plurality of headers. The at least one transmission line may be a 50 Ohm controlled impedance transmission line. The printed circuit board, the ground plane, and the first layer may be at least partially sandwiched between a plurality of leads of the SMA connector. A center conductor of the SMA connector may be connected to the at least one transmission line. 
     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a schematic view of a bayonet nut connector (BNC) dual in-line package (DIP). 
     FIG. 2 illustrates a schematic view of a single sub-miniature series A connector (SMA) DIP. 
     FIG. 3 illustrates a schematic view of a dual SMA single in-line package (SIP). 
     FIG. 4 illustrates a schematic view of a single SMA SIP. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 illustrates a schematic view of an adapter  1  in accordance with a first embodiment. The adapter  1  may be, for example, a BNC DIP adapter. The adapter includes a ground plane  2  having holes  3  and openings  4 . The ground plane  2  may be used to provide an outer grounding surface for an attached RF device. The adapter  1  also includes a printed circuit board (PCB)  5  having holes  6  and openings  7 . The PCB  5  may be formed from plastics, polymer, or resins. The adapter  1  also includes a bottom layer  10  having a soldered side  11 , holes  13 , and openings  15 . The PCB  5  may be connected to the ground plane  2  in a conventional manner. In a preferred configuration, the openings  3 ,  6 , and  13  are vertically or horizontally aligned to receive a plurality of headers  17 , as shown in FIG.  1 . Preferably, the number of openings  3 ,  6 , and  13  is equal to or more than the number of headers  17 . Further, when the ground plane  2 , the PCB  5 , and the bottom layer  10  are secured by the headers  17 , the openings  4 ,  7 , and  15  are substantially aligned to define a footprint to receive a plurality of leads  20  of a BNC connector  21 . The ground plane  2 , the PCB  5 , the headers  17 , the bottom layer  10 , and the BNC connector  21  may be connected in a conventional manner. 
     The adapter  1  preferably includes one or more transmission lines  25  formed on the bottom layer  10 . In one configuration, the transmission line  25  can be used to connect one of the headers  17  to a center conductor  26  of the BNC connector  21 . The transmission line may be a 50 Ohm controlled impedance transmission line or other suitable transmission line. This means that high frequency signals can be used to operate an attached radio frequency connector without excessive noise. 
     The ends  17   b  of the headers  17  may be designed to be secured to any conventional mother board or prototyping board. In one embodiment, the headers may be designed to connect to a standard 100-mill grid pattern mother board. Preferably, ends  17   a  of header  17  are substantially coplanar with the ground plane  2 , when the adapter  1  is assembled. 
     FIG. 2 illustrates a schematic of an adapter  100  in a second embodiment. In this configuration, the adapter  100  may be a single SMA DIP adapter. The adapter  100  includes a top layer  101  having holes  102  and a component side  103 . The adapter  100  also includes a PCB  104  having holes  105 . The PCB  104  may be formed from plastics, polymer, or resins. The adapter  100  also includes a ground plane  110  having holes  112 . The ground plane is configured to provide an outer grounding surface for an attached RF device. The ground plane  110 , and the PCB  104  may be connected in a convention manner. The adapter  100  also includes a plurality of headers  117 . In a preferred configuration, the holes  102 ,  105 , and  112  are vertically or horizontally aligned to receive the headers  117 . Preferably, the ends  117   a  of the headers  117  are substantially coplanar with the component side  103  of the top layer  101 , when the adapter  100  is assembled. The number of holes  102 ,  105 , and  112  may be equal, and may be equal to or more than the number of headers  117 . The bottom side  117   b  of headers  117  may be configured to be adaptable to any conventional mother board or prototyping board. For example, the. bottom sides  117   b  may be configured to be adapted to a standard 100-mill grid pattern mother board. 
     The adapter  100  also includes a SMA connector  123  for receiving a connection from an SMA device. Once configured, the top layer  101 , the PCB  104 , and the ground plane  110  are preferably sandwiched between the leads  129  of the SMA connector  123 . The SMA connector  123  may be mounted to the PCB  104 , top layer  101 , and, the ground plane  110  in a conventional manner. 
     In a preferred configuration, a center conductor  126  of the SMA connector  123  may be coupled to the top layer  101  and to one or more transmission lines  127 . The transmission lines may be 50 Ohm controlled impedance transmission lines. In this way, the signal path from the output of the SMA connector  123  to the mother board can be controlled for impedance matching. 
     FIG. 3 illustrates an adapter  200  in a third embodiment. In this configuration, the adapter may be a dual SMA SIP adapter. The adapter  200  includes a ground plane  201  having holes  202  and openings  203 . The ground plane  201  may be similar to the ground plane  2  described above. The adapter also includes a PCB  204  having holes  205  and openings  206 . The PCB  204  may be similar to the PCB  104  or PCB  5  described above. The adapter  200  also includes a bottom layer  210  having a soldered side  211 , holes  208 , openings  209 , and transmission lines  225 . In a preferred configuration, the PCB  204 , the ground plane  201 , and the bottom layer  210  are coupled to align holes  208 ,  205 , and  202  vertically or horizontally to receive corresponding headers  217 . Preferably, the ends  217   a  of headers  217  are substantially coplanar with the soldered side of the bottom layer  210 , when adapter  200  is assembled. The headers  217  may also include bottom ends  217   b  that are adaptable to any conventional mother board or prototyping board. For example, a standard 100-mill grid pattern mother board may be used. Preferably, the PCB  204 , the bottom layer  210 , and the ground plane  201  are connected together in a conventional manner. The openings  206  may be used to secure the PCB  204 , the bottom layer  210 , and the ground plane  201 . The to openings  206 ,  209 , and  203  may also be used to connect the ground plane to a footprint for the SMA connectors  235  on the PCB  204 . 
     The adapter  200  may also include SMA connectors  235  having leads  229 . Once configured, the PCB  204 , the ground plane  201 , and the bottom layer  210  may be sandwiched between leads  229  in a conventional manner. 
     The adapter  200  may also include one or more transmission lines  225 . The transmission lines  225  may be 50 Ohm controlled impedance transmission lines that are electrically coupled to a center conductor leads  226  of the SMA connectors  235 . Thus, the transmission lines  225  can be used to supply a controlled impedance signal path between the output of the SMA connectors  235  and the selected headers  217 , when the adapter  200  is mounted to the mother board. Advantageously, this limits the amount of noise in the output signal. 
     FIG. 4 illustrates an adapter  300  in accordance with a fourth embodiment. In this configuration, the adapter  300  may be a single SMA SIP adapter. The adapter  300  may include a ground plane  301  similar to ground plane  201  having holes  301  and openings  303 . The adapter  300  may also include a PCB  305  having holes  306  and openings  307 . The PCB  305  may be fabricated from polymer, resins, or plastics. The adapter  300  may also include a bottom layer  310  having a soldered side  311 , holes  313 , and openings  312 . The bottom layer may also include a transmission line  325 . In a preferred configuration, the ground plane  301 , the PCB, and the bottom layer  310  are, configured to align the holes  313 ,  307 , and  302  to receive the headers  317 . Preferably, the ends  317   a  of the headers  317  are substantially coplanar with the soldered side  311  of the bottom layer  310 . The ends  317   b  of headers  317  may be configured to be adaptable to any conventional mother board or prototyping board. For example, the board may have a standard 100-mill grid mother board pattern. 
     The adapter  300  may also include a SMA connector  335  having a plurality of leads  329 . In a preferred configuration, the transmission line  325  is used to couple a center conductor  326  of the SMA connector  335  to one of the headers  317 . Preferably, the PCB  305 , the ground plane  301 , and the bottom layer  310  are sandwiched between selected fingers  329 , when assembled. Further, openings  303 ,  307 , and  312  may be used to connect the PCB  305  to the ground plane  301  and the bottom layer  310 . 
     The preferred adapters are easily mounted to known mother boards or breadboards. Preferably, the adapters include pins that can be easily connected to these known boards. Any known RF connector can be supplied with a suitable interface to operate in the gigahertz frequency without suffering from excessive noise at the output. This is because the preferred adapters are, configured with controlled impedance transmission lines. Preferably, the signal path from the output of the RF connector to a center conductor of the adapters can be electrically connected to the controlled impedance transmission lines. This can substantially preserve the high frequency integrity of the signal. For example, the bandwidths of the preferred adapters on an impedance-matched mother board may be 3.5 gigahertz or more. Accordingly, no additional coaxial cable connections are required. In this way, excessive noise in the output signal from the RF connector can also be minimized. 
     A number of embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, the adapter  1  may be a BNC SIP adapter. Other adapters configured with “F” connectors or similar connectors could also be formed in accordance with the present invention. Accordingly, other embodiments are within the scope of the following claims.