CONSTANT IMPEDANCE HIGH FREQUENCY COAXIAL CONNECTOR

Abstract: A coaxial electrical connector, particularly suited for high frequency ''blind-mate'' connections, remotely located connections, multiple connector assemblies and quick connect-disconnect applications, having two mating plug halves (32, 34), each plug having an inner conductor (46, 75), an outer conductor (42, 44) and a dielectric spacer (68, 70) therebetween, the inner and outer conductor on each plug being of unequal lengths such that one projects beyond the other; the longer inner conductor from one plug and the longer outer conductor form the other plug being designed to overlap each other when the connector is first electrically connected and only partially engaged (Fig. 3), thereby defining an overlap region (54, 56, 58, 60); the inner and outer conductors being shaped and the dielectric material of the spacers being chosen such that along the axis of the partially engaged connector, particularly in the overlap region, the effective outer diameter of the inner conductor (''d'') and the effective inner diameter of the outer conductor (''D'') and the dielectric constant of the material therebetween (''E'') satisfy the equation: Z = 138 (E)<-1/2> log (D/d), where Z is the impedance and is substantially constant along the length of the connector as the plugs (32, 34) are moved from the first electrically connected, partially engaged position to the fully engaged position.

Description: CONSTANT IMPEDANCE HIGH FREQUENCY COAXIAL CONNECTOR DESCRIPTION 1. l££hni£al_Ei&ld This invention relates to coaxial electrical connectors, and more particularly to connectors for use in high frequency applications uhere the connector may not be fully engaged properly such as in quick connect/disconnect connectors and modular multiple connector assemblies for electrically connecting tuo modules together and simultaneously making multiple coaxial connections. 2• Baskanαyn<i_όni Coaxial transmission lines and connectors for use thereuith include generally cylindrical inner and outer conductors uhich are axial ly aligned and separated by a dielectric material. The dielectric uithin a cable is generally a flexible solid or foam uhich holds the inner conductor in the center of the cable and permits the cable to flex or bend as required. The dielectric material uithin a connector is generally a combination of a solid in one region of the connector to hold the conductors in alignment and air in another region * A coaxial transmission line or connector as described above has a characteristic impedance determined by the outer diameter of the inner conductor (referenced by a louer case "d" herein), the inner diameter of the outer conductor (referenced by an upper case "D" herein) and the dielectric constant (referenced by the Greek letter epsilon "€" herein) of the material in the space betueen the tuo conductors uhich forms the signal pathway. As is uell-knoun, the characteristic impedance of a coaxial transmission line is determined by the formula: Z = 138 (6)"^ log (D/d) uhere Z is the impedance of the line. In order for a connector to minimize signal disruption as the signal passes through the connector, it must also have a characteristic impedance at each point along its length uhich matches the impedance of the transmission line as set by the formula above. An impedance mismatch causes severe signal disruption, particularly in high frequency applications above one (1) gigaHertz. As described above, a high frequency coaxial connector uill generally include at least some portion uherein the region betueen the inner and outer conductors is filled uith air and another region uherein the space betueen the inner and outer conductors is filled uith an insulating dielectric solid, such as teflon, to hold the inner conductor in coaxial alignment uith the outer conductor. The dielectric constant of the teflon is different from that of air uhich may in turn be different from the insulating dielectric material used in the coaxial cable. Houever, so long as the impedance as set forth by the formula above remains constant, signal disruption is minimized. Uithin the connector, this requires that the dimensions d and D be adjusted relative to each other at each point uhere the dielectric constant changes such that the impedance Z remains constant. Substantial 1 y all prior art connectors have relied upon a butt joint betueen the tuo halves of the connector, i.e., betueen the male plug and the female plug at the intersection of both the inner and outer conductors to keep the diameters D and d constant at the transition point from one plug to the other. The phrase "butt joint" as used herein refers to a joint uhere tuo facing surfaces, one on the male plug and one on the female plug come together uhen the connectors are connected such that there is no gap betueen the tuo surfaces. In such connectors, the dielectric constant 6 is also generally the same on both sides of the transition point from the male to the female plug. The required condition of constant impedance along the length of the engaged connector is achieved by closing the gap betueen the plugs sufficiently that it can be ignored at the maximum frequency that the connector is designed to operate. In a typical coaxial connector design, the outer conductor of the female plug is enlarged at its free end (thereby increasing D) . This permits the outer conductor of the male plug to slide into the enlarged outer conductor of the female plug and make a butt joint (and a good mechanical and electrical connection) betueen the end of the male connector and the inside lip of the outer conductor on the female connector. A similar arrangement occurs at the inner conductor uhere the free end of the inner conductor of the male plug usually has a reduced diameter (decreased d) uhich fits into an axial hole in the inner conductor of the female plug. For a proper connection in such a prior art connector the plugs must be fully seated and there must be essentially no gap at the butted junctions betueen the inner and outer conductors of the male and female plugs. Only uith the gap substantially closed can the increased D and decreased d of the outer and inner connectors be ignored. In such prior art connectors, even a relatively narrou gap, particularly at high frequencies, can substantially disrupt the signal as it passes through the connector by creating an impedance mismatch at the gap due to the uncontrolled variation of the diameters D and d in the gap required by the mechanical design constraints of the connector. In order to close the gap in a butted connector, many high frequency connectors have relied upon screu threads on one plug and a threaded collar on the other plug uhich must be engaged and tightened to a specified torque to insure that the gap betueen the tuo connectors is reduced to a permissably small value. Unfortunately, in many applications, it is not practical to obtain a torque urench and fully seat each connector. Specific problems are encountered uith multiple connectors and "blind-mate" or remotely located connectors or uhere quick connect operation is required. Uhere multiple connections must be made simultaneously one or more of the multiple connectors may not be fully seated even though the remaining connectors are properly positioned. "Blind-mate" connectors are connectors used at the back end of a sliding module, for example, uhich makes all the necessary connections as the module slides into place. Such connectors are often "remotely located" in the sense that a fastener at the front of the module sets the location of the back of the module having one half of the connector, the other half being positioned on the frame in uhich the module is placed. Accordingly, the locating mechanism uhich determines the depth of insertion of one plug into the other is "remotely located" from the plugs themselves. Manufacturing tolerance variations or simple uarps in the mounting frame all directly affect the gap betueen the tuo plugs. To resolve these difficulties, coaxial connector designers have devised various methods to minimize the size of the gap. For example, United States Patent No. 4,426,127 issued to Kυbota shous a coaxial connector uherein the gap region betueen the male and female outer conductors as uell as the gap region betueen the male and female inner conductors are filled by spring members uhich deform as the connection is made to minimize the size of the gap betueen the conductors over a small range of displacement betueen the tuo plugs. Houever, this design still uses a butted type of connection uherein the critical diameters D and d are intended to remain constant at the transition point from the male to female plug. The spring mechanism is only effective over a very short distance of about 10 to 15 thousandths of an inch (0.25 - 0.38 mm). Unfortunately, gaps in excess of the range compensated by this design are quite common in the multiple connector and modular applications described above. Accordingly, the present invention employs a novel design uherein the inner and outer conductors on the male and female plugs do not need to "butt" into each other. Instead, the conductors are designed to form an overlap region betueen the tuo plug halves uhich roughly corresponds to the gap in a prior art connector, the overlap region being intentionally designed so that it may form part of the signal pathuay and have an impedance uhich matches the rest of the connector. Accordingly, the connector has a constant impedance along its entire length from the moment its tuo halves are first electrically engaged, and the size of the "gap" or overlap region may be made as large as desired uithout affecting the impedance of the connector. In accordance uith the present invention, a connector is provided having a first plug for connection to a mating second plug. The first plug as shoun in the drauings can be considered the male plug and the second plug can be considered to be the female plug, houever, due to the design of the optional shield on the male plug uhich makes a female-type connection, the terms first and second plugs uill be used to avoid confusion. Each plug is provided uith an inner conductor, an outer conductor and a dielectric spacer therebetueen and in each, the inner and outer conductors are of unequal length at their free end such that one projects beyond the other. The inner and outer conductors of the first plug are designed to mate uith the inner and outer conductors of the second plug. The plugs are designed such that the longer inner conductor and the longer outer conductor from the first and second plugs overlap each other as the connector is first electrically connected and only partially engaged. This defines an overlap region betueen the inner conductor from one plug and the outer conductor from the other. The inner and outer conductors are shaped, particularly in their relative diameters d and D, and the dielectric material of the spacers is chosen such that along the axis of the partially engaged connector, particularly uithin the overlap region, the effective outer diameter of the inner conductor (d) and the effective inner diameter of the outer conductor (D) and the dielectric constant of the medium therebetueen ( 6) satisfy the equation: Z = 138 (6)-^ log (D/d) uhere Z is the impedance and is substantially constant along the length of the connector as the plugs are moved from the first electrically connected, partially engaged position to the fully engaged position. Bci£f_D≤s£ci£iifln_Qf_ih£_DcayiDas The details of this invention uill be described in connection uith the accompanying drauings in uhich: Fig. 1 is a perspective vieu of a connector according to the present invention. It should be noted that this vi-eu obscures several of the important characteristics of the invention uhich can be seen only in the longitudinal section vieus. Fig. 2 is a side elevation, mostly in longitudinal section along the line 2-2 of Fig. 1. Fig. 3 is a longitudinal section vieu of the connector shouing the first and second plugs partially engaged. Figs. 4 and 5 are end vieus into the open mating ends, i.e. the "free" ends, of the connectors taken along the lines 4-4 and 5-5 marked in Fig 2, respectively. Fig. 6 is a longitudinal section vieu of a single prior art" connector, and Fig. 7 is a longitudinal section vieu of a three connector block using the connector of the present invention shouing one of the connectors being not fully engaged. Q≤iail£d_D≤s£ci£iifln_β£_ih≤_Inγ≤ni.iflD 1• EEifl£_OEi_£Qiιιι≤£ifln Fig. 6 shous a longitudinal section vieu of a simplified prior art connector. A discussion of this connector and the problems encountered uhen the connector is not fully seated uill be helpful in understanding the present invention. The prior art connector seen in Fig. 6 comprises a male plug 10 and a female plug 12. The male plug comprises an outer conductor 14 having an inner diameter Dj, and an inner conductor 16 having an outer diameter di uhich is coaxially aligned uith the outer conductor. The female plug 12 also includes an outer conductor 18 and an inner conductor 20 having the same critical diameters Di and d in the major portion of its body as in the male plug. The space betueen the inner and outer conductors is filled uith a dielectric material 22 having a dielectric constant 6. In this particular simplified example, the dielectric material is shoun to extend throughout the interior of the plug, houever in many connectors, only a portion of each plug is filled uith the dielectric material; the remaining portions being open uherein the dielectric material is air. In any event, the plugs shoun in Fig. 6 are shoun to be not fully engaged, having a small gap betueen the plugs. As described above, the characteristic impedance of the male plug is described by the formula: This formula also describes the characteristic impedance of the female half of the connector 12, and accordingly if the plugs uere fully seated, the male outer conductor 14 and the female outer conductor 18 uould be butted together at faces 24, 26 as uould the inner conductors 16 and 20 at faces 28, 30 thereby providing a constant impedance along the entire length of the connector. Houever, as described above there are many applications uherein it is not possible to insure that the connector is fully seated and accordingly a gap develops as shoun in Fig. 6. Uithin the gap region, the outer conductor 18 of the female plug has an enlarged inner diameter D2» Similarly, the inner conductor 16 of the male plug has a reduced outer diameter d2 as required to make the connections betueen the male 10 and female plugs 12. Accordingly, uithin the gap region, the impedance of the connector is described by the formula: Zg a p = 138 (e a i r >-*$ log ( D2/d2> • For the situation shoun in Fig. 6, all three critical parameters, €, D, d are different uithin the gap region as compared to their values uithin the transmission line and the remaining portions of the ' connector, and all three have been undesirably altered such that the impedance Z gap is increased. In particular, the dielectric constant of air (€ a i r ) is generally less than that of the dielectric constant of most solid dielectrics uhich are commonly in use thereby increasing the factor (6)"^. Moreover, the increased D and decreased d in the gap both act to increase the ratio D2 d2 thereby increasing the factor log ( D2 d2 as compared to log (Dj/di). Consequently, all three factors act to increase the impedance Z gap thereby causing an impedance mismatch uith resulting signal degradation. Although in this simplified example all three parameters D, d and 6 changed to cause the mismatch, a change in any single one of the parameters due to a gap uould be sufficient to cause a problem at high frequencies. E_i£££_iL_ι_l_E-il_Q_li_ι_i[it__ι£_t £_CQQα_ι_Lt_ι_ι Fig. 1 shous a perspective vieu of the preferred embodiment of the connector. Many of the important features of the connector, houever, are internal and are obscured by the exterior vieu seen in Fig. 1. Nonetheless, this figure is helpful for general orientation regarding the connector. The connector is comprised of a first plug 32, and a second plug 34. The tuo plugs each have various enlarged rings 36, 38 around their circumference uhich are principally used to attach the individual plugs 32, 34 to a connector housing (not shoun, but indicated generally in Fig. 7) for use in multiple connector modular asse bl ies. The first plug includes a shield 40 uith slots 42 uhich permits the shield 40 to be compressed slightly during manufacture thereby making firm electrical contact uith the outer conductor 44 on the second plug 34 uhen the plugs are engaged. Also visible on the first plug 32 is a portion of the free end of the inner conductor 46 of the first plug, the free end being the end uhich connects to the other plug. Similarly, on the second plug 34 a portion of its inner conductor 48 can be seen. In this vieu, houever, the visible end of the inner conductor 48 is the end for connection to the coaxial transmission line, not the free end. This end can have any standard configuration knoun to the art for making a connection to a coaxial transmission line. The end may be straight or right-angled and generally involves a soldered joint uhich makes a good 1 ou loss, substantially constant impedance connection betueen the coaxial transmission line and the second plug. A similar connection is made betueen the far end (not visible in Fig. 1) of the first plug 32 and its respective coaxial transmission line. Fig. 2 is a side elevational vieu of the connector along the line 2-2 seen in Fig. 1. This vieu is taken mostly in section in order to illustrate the important features of the invention. For purposes of description, first plug 32 can be divided into four regions marked uith reference numerals 50-56 uhich correspond to four regions on the second plug 34 marked uith reference numerals 58-64. In the preferred embodiment, first plug 32 comprises four separate mechanical pieces, namely, the inner conductor 46, the outer conductor 66, the shield 40 and a dielectric spacer 68. The second plug 34 comprises three pieces including the inner conductor 48, the outer conductor 44 and the dielectric spacer 70. Regions 50 and 64 in the first and second plugs respectively are the coaxial cable connection regions, i.e., the regions in uhich the signal first passes from the coaxial cable into or out of the connector. As indicated above, these regions are designed uith standard techniques to mate uith the specified coaxial cable and provide an exact impedance match such that the signal is transferred effectively to the first and second plugs respectivel y. Generally, to make this connection, the outer conductor and the dielectric material of the coaxial cable are stripped back from the inner conductor of the coaxial cable. The inner conductor of the coaxial cable is inserted into the inner conductor 46 of the first plug 32 in the axial opening marked uith reference numeral 72. A corresponding axial opening 73 is provided in inner conductor 48. To the left of region 50 and to the right of region 64, the signal is passing in the pathuay defined betueen the inner and outer conductors of the coaxial cable. Uithin regions 50 and 64, the signal is in the pathuay defined betueen the shield 40 and the inner conductor 72 in the first plug 32, and betueen the outer conductor 44 and the inner conductor 48 in the second plug 34. The space betueen these regions is filled uith air. It uill be understood that in first plug 32, the leftmost portion of shield 40 in region 50 acts as the outer conductor and defines the critical diameter D in that region. Reference to Fig. 3 shous that the critical diameter ratio D3 d3 defines the impedance of the connector in region 50 according to the formula: Z = 138 ( a i r )-^ log (D 3 /d3) The diameters D and d in region 64 may be the same as in region 50, and must have the same ratio D3/d3 because the dielectric material is the same (air) in both regions. Houever, in the preferred embodiment, they are slightly different than D3 and d3, for simplified assembly of the final connector. Regions 52 and 62 are the dielectric spacer regions uherein the space betueen the inner conductor and outer conductor on each plug is filled uith a dielectric spacer. The dielectric spacer is preferably made of teflon, houever, it may be of any of the many suitable dielectric materials uhich are uell-knoun for use in high frequency connectors. The dielectric spacer holds the connector together, keeping the inner conductors axial ly aligned in the center of the outer conductors in each plug. Because the dielectric constant of the preferred teflon is greater than the dielectric constant of air, the diameters D4,d4 in region 52 (see Fig. 3) must be adjusted to maintain the impedance uithin region 52 to match the impedance uithin region 50 and uithin the coaxial cable itself. Accordingly, uithin region 52, the diameters 4,d4 are chosen such that: €t e i on )-^log D4/d4)=(e a i r )-^log(D 3 /d3) This type of adjustment of the critical diameters D and d as the dielectric constant changes from one region to another is uell-knoun. An important feature to note is that the transition from diameter D3 to D4 does not occur in exactly the same plane as the transition from d3 to d4 as one might expect. This offsetting of the transitions of the inner and outer conductors is an empirically derived adjustment required because the impedance formula given above is completely accurate for the actual measured diameters D and d only in regions uhere the electric field lines are substantially radially aligned in the connector. This occurs only uhere the inner and outer diameters (d and D ) are not changing rapidly. The formula does not give completely accurate results in regions uhere the diameters d and D are rapidly changing uhich causes the electric field lines to diverge from their radial al ignment . In the vicinity of a sharp corner on the surface of the inner or outer conductor, the electric field lines tend to point touard the corner and thus the "effective" internal and external diameters D,d differ slightly from the actual diameters uhich are measured radially. Essentially, the "effective" diameters d,D uhen substituted into the formula above produce the actual impedance in the vicinity of a rapid change in the actual diameters D,d. The effective diameters, houever, are quite close to the actual diameters even at the points of rapid transition of actual diameters. In regions uhere the actual diameter is unchanging, the effective diameter equals the actual measured diameter. It is the actual diameter uhich is generally used to calculate the impedance of the connector. Houever, it is the effective diameter uhich must be controlled even though most practitioners of the art of designing such connectors fail to distinguish the tuo. The consequence of this is that in order to maintain a constant impedance through a region uhere the conductor diameters are changing, it is necessary to offset the diameter changes in the inner and outer conductors by a slight amount based upon the extent of the diameter change to be made. This requirement is uell knoun to coaxial connector designers and represents a small adjustment to the idealized case uhere the tuo diameter changes uould occur in the same plane * The adjustment may be easily estimated by those uith experience in the field. The regions marked uith reference numerals 54 and 60 may be referred to herein as the "free space" regions. Uithin region 54, as uithin region 50, the relative diameters Ds,d5 as indicated in Fig. 3 are selected once again to match the characteristic impedance of the remaining portions of the connector * As in region 50, the dielectric material betueen the inner conductor 46 and the outer conductor 66 is air and accordingly the ratio Ds d5 must be the same as the ratio D3 d3 * It can be seen in Fig. 2 that the outer conductor 66 uithin region 54 has slots 74 uhich permit the free end of outer conductor 66 to be slightly enlarged thereby making electrical contact at its free end uith the interior of the outer conductor of the second plug 44. In region 56, the inner conductor of the first plug 46 projects beyond the outer conductor 66. As can be seen most clearly in Fig. 3, the projecting end of the inner conductor 46 in region 56 is enlarged in region 56, having an outer diameter d $ uhich is greater than its diameter ά~> in region 54. As can be seen clearly in Fig. 2, the inner conductor 66 stops short of region 56. The outer shield conductor 40 does not form part of the signal passageuay uhen the connector is connected. Accordingly, the projecting portion of the inner conductor 46 in region 56, having a diameter d$» has as its corresponding outer conductor, the outer conductor 44 on the second plug in region 58 uhich has an inner diameter D$ as marked in Fig. 2. Referring to the second plug in Fig. 2, the operational similarity of the second plug to the first plug can be seen * Considering nou a signal passing from the right side of Fig. 2 touards the left, the signal uould enter the connector from the coaxial cable as previously described, entering regions 64, passing into region 62 and then into region 60, each of the regions described, 60-64 having the same characteristic impedance as the coaxial cable and as the corresponding regions 50-54 in the first plug. Just as in the first plug, the inner and outer conductors 48, 44 in the second plug are of unequal lengths. In the second plug, the longer conductor is the outer conductor 44 uhich projects beyond the inner conductor 48 in region 58. Once again, in the projection region 58, as in region 56, the projecting member, uhich for the second plug is the outer conductor 44, has a change of its critical diameter as it goes from the free-space region 60 to the region 58. For the outer conductor 44, the critical diameter is its inner diameter D uhich changes to the reduced diameter D^ in region 58 as compared to the corresponding larger inner diameter D in region 60. In the preferred embodiment, regions 54, 56, 58 and 60 all have substantially the same length and, accordingly, as the connectors are engaged, the outer conductor 44 on the second plug in region 58 slides into the interior of the shield 40 on the first plug until the tuo outer conductors 66 and 44 contact each other. At approximately this point, the inner conductors 46 and 48 also make contact and the connectors form the electrical connection. From the instant the electrical connection is formed, the connector has an overlap region defined by the overlap betueen regions 56 and 58. Uithin this region, the enlarged projecting portion of the inner conductor 46 and the reduced projecting portion of the outer conductor 44 form a transitional signal pathuay betueen the tuo plugs having a characteristic impedance defined by the ratio D^/d^. These diameters are chosen to provide a matching impedance to the impedance elseuhere in the connector^—and-it—is this match uhich is essential to producing a constant impedance along the length of the connector, even uhen the connector is only partially engaged. As the connectors slide from the "just-barely" engaged position to the fully engaged position, the overlap region betueen regions 56 and 58 diminishes in size as the outer conductor 44 slides over the outer conductor 66 and ceases to function as part of the signal pathuay. Similarly, the projecting end of inner conductor 46 slides into the inner conductor 48 and also ceases to function as part of the signal pathuay. It can be clearly seen that the length of the overlapping connectors can be made as great as desired to provide any desired tolerance for the connector. In the preferred embodiment, regions 54, 56, 58 and 60 are all approximately 0.10 inches (2.5 mm) in length uhich is more than sufficient for compensating for the variations in the depth of engagement of the tuo plugs uhich might occur in any of the applications previously discussed. The preferred length of regions 54, 56, 58 and 60 all provide a compensation uhich is about 10 times greater than prior art compensating designs. Because the overlap region is designed to form part of the signal pathuay uith a matching impedance to the rest of the connector, it is not necessary that the connector be fully engaged. It is perfectly suitable for the connector to be used in applications uhere it might aluays be partially engaged * It can be seen in Figs * 3 and 5 that the free end of inner conductor 48 may be provided uith slots 75. The end may then be lightly compressed to make electrical contact uith the free end of inner conductor 46. All of the slots, seen best in Figs. 4 and 5, and the compression or expansion of the slotted members are optional and may be adjusted as desired to suit the appl ication. The various components of the connectors are manufactured, the conductive components usually being plated uith a highly conductive non-oxidizing material such as gold, and then assembled. The dielectric spacers 68, 70 may be held in position by adhesive or by lightly crimping or indenting the exterior of the outer conductors. Connectors according to the invention uork quite uell at frequencies above 1 gigaHertz and have been tested to at least 18 gigaHertz. Fig. 7 shous a plurality of the connectors of the present invention identified uith reference numerals 76, 78, 80. The first plugs of each connector are mounted in a connector block 82 and the second plugs are mounted in connector block 84. Typically, connector block 82 uould be mounted to the back of an electrical module and connector block 84 uould be mounted to the rear of a frame into uhich the electrical module uould slide such that the connectors uould mate uhen the module uas positioned uithin the frame * As can be seen in Fig. 7, connectors 76 and 80 are fully seated uhereas connector 78 is shoun to be only partially seated due to some misalignment. or manufacturing variation. Accordingly, the region marked uith reference numeral 86 uould, in a prior art connector, be a gap causing an impedance mismatch through connector 78, houever in the present connector this is the overlap region uhich is designed to form part of the signal pathuay and uhich includes a characteristic impedance uhich matches the impedance elseuhere in the connectors and transmission 1 ine.

Claims: CLAIMS 1. A coaxial electrical connector comprising: a first plug having a free end for connection to a second plug, an inner conductor, an outer conductor and a dielectric spacer therebetueen, the inner and outer conductors of the first plug being of unequal lengths at the free end such that one projects beyond the other; and a second plug having a free end for connection to the first plug, an inner conductor, an outer conductor and a dielectric spacer therebetueen, the inner and outer conductors of the second pl^g alsjD be_i g of unequal lengths at the free end to contact the inner and outer conductors of the first plug; uherein the longer inner conductor and the longer outer conductor from the first and second plugs overlap each other uhen the connector is first electrically connected and only partially engaged thereby defining an overlap region; and uherein the inner and outer conductors are shaped and the dielectric material of the spacers is chosen such that along the axis of the partially engaged connector, including in the overlap region, the effective outer diameter of the inner conductor (referenced by "d") , the effective inner diameter of the outer conductor (referenced by "D") and the dielectric constant of the medium therebetueen (referenced by "€") satisfy the equation: Z = 138 6)-** log (D/d) uhere Z is the impedance and is substantially constant along the length of the connector as the plugs are moved from the first electrically connected, partially engaged position to the fully engaged position. 2 * An electrical connector according to claim 1 uherein the first plug includes the longer inner conductor and the second plug includes the longer outer conductor; said longer inner conductor having a larger diameter in the region uhere it projects beyond the outer conductor of the first plug than in the region uhere it is surrounded by said outer conductor of the first plug; and, said larger outer conductor having a smaller inner diameter in the region uhere it projects beyond the inner conductor of the second plug than in the region uhere it surrounds said inner conductor of the second plug * 3. An electrical connector according to claim 2 uherein the outer conductor of the first plug is slotted and slightly expanded at its free end to make connection to the interior of the outer conductor of the second plug. 4 * An electrical connector according to claim 2 uherein the inner conductor of the second plug is slotted and slightly compressed at its free end to make connection to the extension of the inner conductor of the first plug. 5. An electrical connector according to claim 2 uherein the length of the enlarged projecting portion of the inner conductor of the first plug is substantially the same as the length of the projecting portion of the outer conductor of the second plug. 6. An electrical connector according to claim 1 uherein the dielectric spacers are formed of teflon. 7. An electrical connector according to claim 1 further including an electrically conductive shield substantially surrounding the free end of the first plug and formed to mate uith and substantially surround the free end of the outer conductor of the second plug uhen the plugs are engaged * 8. An electrical connector according to claim 7 uherein the shield is slotted and slightly compressed at its free end to make connection uith the exterior of the second plug* . ___ 9. An electrical connector according to claim 1 uherein the overlap region forms part of the signal pathuay even uith the connector fully engaged * 10. A plurality of electrical connectors according to claim 1 uherein at least one of the plugs of each connector is mounted in a connector block. 11. A plurality of electrical connectors according to claim 10 uherein both plugs of each connector are mounted in opposing connector blocks uhereby all the connectors may be disconnected and connected substantially simultaneously.

Inventors: HUBBARD GEORGE M, HUBBARD, GEORGE, M.
Applicants: PALCO CONNECTOR INC, PALCO CONNECTOR INC.
Application year: 1988
Main classification: H01R17
IPC codes: H01R13, H01R24, H03H7