US2417895A

US2417895A - Balanced to unbalanced circuit connector

Info

Publication number: US2417895A
Application number: US597655A
Authority: US
Inventors: Harold A Wheeler
Original assignee: Hazeltine Research Inc
Current assignee: Hazeltine Research Inc
Priority date: 1945-06-05
Filing date: 1945-06-05
Publication date: 1947-03-25
Anticipated expiration: 1964-03-25
Also published as: FR938516A; BE469469A; DE837404C; GB611982A

Description

H. A. WHEELER BALANCED '10 UNBALANCED CIRCUIT CONNECTOR ZAW,

Fi led June 5, 1945 2 Sheets-Sheet 1 SHURT-WAVE Q SIGNAL GENERATOR 0 7* Nu X 3d 3 (lmpadame Z $.36 PX am Ila mm-m I 7 F; g gl V l3 hnmdance 2 T A 30 3g Hmpedcnca; Z.)

I l INVENTOR 2/ no HAROLD A. WHEELER (\mpaaunce Z ATTOR NEY m T C E N N o m. R w Lm "m0 H m m T MW 0 T D E c N A L A B arch 25, 1947.

Filed June 5, 1945 2 Sheets-Sheet 2 R r Y E M M M ni h V 0 N W ID A lmpadunw Z Patentecl Mar. 25, 1947 BALANCED 'ro nrmnmncan CIRCUIT connnoron Harold A. Wheeler, Great NeclnN. Y, assignor, by mesne assignments, to liazeltine Research, Inc, Chicago, Ill., a corporation of Illinois Application June 5, 1945, Serial No. 597,655

15 Claims. (01. 178-44) through to a balanced circuit. A pair of thin longitudinal slots are cut into one end of the outer conductor or shieldof the coaxial line so that the shield at the slotted end comprises a pair of conductive portions. Usually, the slot length is such that the pair of conductive portions individually have an electrical length equal to onequarter of the mean operating wave length of the connector. The inner conductor of the coaxial line is bonded at the end to one of the conductive portions provided in the slotted section of the shield. With this construction, one end of the connector may be utilized as a conventional unbalanced transmission line adapted for direct connection with the unbalanced circuit. At the other end of the connector, the two conductive portions of the shield may be utilized as balanced terminals for connection with the balanced circuit.

The described connector is desirable from a mechanical standpoint in view of its simplicity but it has certain electrical characteristics which may be undesirable in particular installations. It has been discovered experimentally that the expedient of slotting the shield conductor and bonding the inner conductor to one of the resulting shield portions causes the chraracteristic impedance of the balanced circuit provided at one end of the connector to be twice that of the unbalanced circuit provided at the opposite end. In other words, an impedance discontinuity is encountered at the junction of the balanced and unbalanced circuit portions of the connector. Since reflections arise at points of impedance discontinuity, the prior-art connector is unsuited for certain installations.

It is an object of the present invention, therefore, to provide a balanced-to-unbalanced circuit connector which substantially avoids the aforementioned limitationzof prior-connectors.

It .is another object 'of the invention, 'to provide an improved balanced-tounbalanced circuit connector having a substantially uniform characteristic impedance throughout its balanced and unbalanced circuit portions.

It is a specific object of the invention to provide an improved balanced-to-unbalanced circuit connector of the coaxial type for operation over a wide range of wave lengths.

A balanced-to-unbalanced circuit connector in accordance with the present invention comprises an outer conductor including a first section and a contiguous second section. The second section has a pair of longitudinal slots extending from one end of the outer conductor and forming in the second section a pair of conductive portions. The connector also has an inner conductor including a first section and a contiguous second section coaxially supported within the first and second sections, respectively, of the outer conductor. The inner conductor is connected to one of the conductive portions formed in the outer conductor substantially at the free end thereof. The first sections of the inner andouter conductors have a, relative spacing selected to provide an unbalanced transmission line having a predetermined characteristic impedance at a given operating wave length. The second sections of the inner and outer conductors have a relative spacing selected so that the second section of the inner conductor and the other one of the pair of conductive portions provide a balanced transmission line having approximately the aforesaid predetermined characteristic impedance.

For a better understanding of the present invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

In the drawings, Fig. 1 is a view, partially in cross section, showing a circuit connector in accordance with the present invention connecting an antenna system to a wave-signal generator; Fig. 2 is an end view of the balanced circuit portion of the connector; Fig. 3 is a schematic circuit diagram of the Fig. 1 connector; Figs. 3a3d,

inclusive, are used in assimilating the individual circuit portions of Fig. 3 with the mechanical connector arrangement of Fig. 1; Fig. 4 is an end view of the balanced-circuit portion of a modified connector of the type of Fig. 1; Fig. 5 is a similar end view of a, further modification 0f the Fig. 1 arrangement; Fig. 6 represents another embodiment of the invention; Fig. 7 is an end view of the balanced-circuit portion of the Fig. 6 concular in cross section. Each conductor includes a first sect on and a contiguous second section, the first sections being only partially shown and the second sect-ions having a length designated by dimension line L. More particularly, the outer conductor has a grounded first section II) which may have any length desired in accordance with the intended use of the connector. For this reason only a portion of this section is illustrated. The second section of the outer conductor is designated Ila, IIb and, in a preferred embodiment of the invention, has a length L approximately equal to one-quarter of the mean operating wave length of the connector. This second section of the outer conductor, as shown in Fig. 2, has a pair of diametrically opposed, thin longitudinal slots I4 and I5 extending throughout the entire length of the second section. These slots form in the second section of the outer conductorthe pair of conductive portions Ila and III), which may individually have an electrical length equal to onequarter of the mean operating wave length.

The first and second sections of the inner conductor are designated I2 and I3, respectively. They are coaxially supported, by means of suitable insulating spacers IE, IS, within the first and second sections, respectively, of the outer conductor. The inner conductor is connected to one of the conductive portions formed in the second section of the outer conductor. For this purpose, the free end of inner-conductor section I3 is supported by a semi-circular conductive member I1 which is soldered, welded, or otherwise conductively connected to and supported by the free end of portion Ilb of the outer conductor.

The first sections I ll and I2 of the inner and outer conductors have a relative spacing selected to provide an unbalanced transmission line having a predetermined characteristic impedance at the mean operating wave length. This unbalanced transmission line may be directly connected with a signal-translating arrangement, such as the short-wave signal generator 20 having an unbalanced output circuit. The second sections Ila, IIb and I3 of the inner and outer conductors have a relative spacing selected so that the second section I 3 of the inner conductor and conductive portion Ila of the outer conductor provide a balanced transmission line, having approximaely the same characteristic impedance at the mean operating'wave length as the unbalanced line provided by sections III and I2. The balanced transmission line is directly connected with a dipole antenna consisting of a pair of radiating elements 25 and 2B, individually having an efiective electrical length equal to onequarter of the mean operating wave length. Radiating element 25 is directly connected with conductive portion Ila of the balanced transmission line, while the alternate radiating element 26 is connected with the remaining conductor l3 of the balanced line.

The electrical circuits represented by the mechanlcal structure of Fig. 1 are illustrated schematically in Fig. 3. Figs. 3a to 3d, inclusive, indicate the conductive elements of the connector which are the counterparts of the conductors of Fig. 3. The directional arrows 3a-3a to 3d-3d denote the circuit portions represented by Figs. 3a3d and the impedance notations associated with each such figure designate the characteristic impedance of the particular circuti portion. In Fig. 3 conductors l0 and I2 constitute an unbalanced transmission line. As shown in Fig. 3a, this unbalanced-line portion is provided by sections I0 and I2 of the outer and inner conductors, respectively, of the connector. It has a characteristic impedance Z0 determined by the relative diameters of its coaxial conductors. Assuming the outer conductor of the connector to have a uniform and preselected diameter equal to do, the diameter (11 oi inner-conductor section I2 is selected with reference thereto in order to obtain the desired characteristic impedance Z0 for the unbalanced-line portion of the connector. This portion extends from the unbalanced input terminals of the connector to which generator 20 is connected to the junction of the first and second sections of the inner and outer conductors. The junction is designated by the broken line AA in Fig. 3.

The balanced transmission-line portion of the connector starts at the junction A-A. It is formed of the conductors Ila and I3 which, as shown in Fig. 3b, are provided by section IIa of the outer conductor and one-half of inner conductor section I3, where section I3 is bisected by an imaginary plane X-X. The plane X-X bisects the inner and outer conductors of the connector and is normal to the plane of the drawings. The balanced line Ila, l3 has a characteristic impedance Z1 determined by the relative spacing or diameters of its conductors. The specific conductor spacing and the resulting value of the characteristic impedance is to be particularly described hereinafter.

Electrically, the connector also embodies a pair of stub lines located at the opposite terminal portions of the balanced-line portion Ila, l3. The first such stub line, coupled to the balancedline portion at junction A-A, includes conductors Ill) and I3". As shown in Fig. 30, these conductors are provided b outer conductor section IIb and one-half of inner conductor section I3. Since member I! bonds the ends of these conductors together, as indicated at 11', the first stub line Ilb', I3" is a short-circuited line section. It has a characteristic impedance Z1 which is equal to that of the balanced-line portion I la, I3 since, in the Fig. 1 arrangement, the conductors of these two line sections are identical in construction and spacing.

The second stub line, located at the free end of the balanced-line portion Ila, I3 includes conductors Ila" and Ilb". As shown in Fig. 3d, these conductors are provided by the conductive portions Ila and I lb formed in the outer conductor by slots III and I5. Since the conductive portions I la and ill) are joined at the closed ends of slots I4 and I5, the second stub line Ila", Ilb" is also a short-circuited line section. It has a characteristic impedance Z: which may be controlled by variations in the width of slots I4 and I5. This impedance Z2 may be considered as the balanced characteristic impedance of the outer conductor, that is, the impedance of the slots and the outside of the slotted section of the outer conductor. This second stub line represents necessary to establish a uniform characteristic impedance between the balanced and unbalanced-line portions of the connector may readily be determined. It becomes apparent immediately that the impedance Z1 of the balancedline ortion IIa, I3 must be approximately equal to the characteristic impedance Z of the unbalanced-line portion III, I2. This result is obtained by appropriately selecting the diameter (12 of inner-conductor section I3 with reference to the diameter do of the outer conductor. In the Fig. 1 embodiment the same dielectric material (air) fills the inter-conductor space in the balanced and unbalanced-circuit portions of the connector. For this reason, the balanced and unbalanced-line portions have equal characteristic impedances, as required, by selecting the diameter d2 of inner-conductor section I3 to be equal to the geometric mean of the diameters do and d1 of conductor sections Ill and I2, respectively. By thus selecting the spacing of the first sections of the inner and outer conductors as well as the spacing of the second sections of these conductors, the balanced and unbalanced-line portionsof the connector represent a uniform characteristic impedance. Where this impedance equals the unbalanced terminal impedance of generator 20 and the balanced terminal impedance of

dipole antenna

25, 26, maximum power transfer between the generator and the antenna results. Before considering the wide-band operating characteristics of the connector of Fig. 1, it is expedient to view the impedance relationships of its balanced and unbalanced-line portions from a slightly different viewpoint.

It has been stated with reference to Figs. 3 and 3a that the unbalanced-line portion ID, I2 has a characteristic impedance Z0 and is provided by conductor sections ii) and I2. Since section I0 is grounded and constitutes a sheath enclosing section I2, the unbalanced-line portion may be viewed as comprising a pair of unbalanced lines connected in parallel and individually having a characteristic impedanceequal to 2Z0. One of this pair of lines consists of one-half of each ofconductor sections In and I2, while the other is provided by the remaining halves of these sections, and the imaginary plane X-X designates the meeting plane of the two lines. Therefore, if the contiguous second sections of the inner and outer conductors which provide the balanced-line portion I-Ia', I3 of the connector have the same diameters and dielectric loading as their first sections, an impedance discontinuity is caused at the junction AA. The discontinuity arises because the balanced-line portion Ila, I3, assuming the inner and outer conductors of the connector to have uniform diameters and dielectric loading, is formed of conductors having the same spacing as the conductors of each of the pair of parallel-connected unbalanced lines eiiective- 1y included in unbalanced portion I0, I 2' and consequently its characteristic impedance Z1 is equal to 220. In other words, where the inner and outer conductors of the connector have uniform diameters and a homogeneous dielectric therebetween, such as air, the unbalanced-line portion I0, I2'- has an impedance Z0 and the balanced-line portion Ila, I3 has an imped- 6 ance of twice that value. This discontinuity is encountered in the prior connectors referred to above but is avoided in the Fig. 1 embodiment by enlarging the diameter of inner conductor Hit The change in diameter is selected so that the characteristic impedance Z1 orthe. balanced-line portion is approximately equal to that of the unbalanced-line portion.

For optimum operation over a wide range of wave lengths, the matched impedance relation between the balanced and unbalanced-line portions of the connector is established at the mean operating wave length. Also, the slots I4 and I5 have a length L equal to one-quarter of the mean wave length. Where these conditions are satisfled, each of the stub lines IIb', I3" and Ila",

III)" represents a short-circuited quarter-wave line. At the mean operating wave length each line is then equivalent to an infinite impedance or an open circuit. I The first stub line No,

I3 has the same characteristic impedance Zi as the balanced-line portion Ila, I3. optimum wide-band operation, line IIa, IIb" should have an equal characteristic impedance.- This is obtained by appropriately selecting the width of slots Id and I5. With quarter-wave short-circuited stub lines individually having a characteristic impedance substantially equal to that of the balanced-line portion of the connector, optimum wide-band operation results since. the impedance variations of the stub lines cancel one another at the operating wave lengths of the desired range.

In certain applications, the connector may be constructed to compensate for impedance variations of the balanced-circuit arrangement For the second stub coupled thereto. Consider, for example, the case I in which the

balanced dipole antenna

25, 26 is series-resonant at the mean wave length of the operating band. The impedance of the antenna is, therefore, a minimum at the mean Wave length and increases with wave length variations in either direction therefrom. To compensate for such impedance variations of the antenna, loading means may be provided adjacent to the conductive portions Ila and Nb of the outer conductor for appropriately determining the characteristic impedance Z2 of the second stub line. Such a modification of the connector is represented in Fig. 4 which is an end view of the balanced-line portion. As illustrated, horizontally disposed flange members 2i, 2| extend from and along the length of conductive portion II a.

Similar flange members

22, 22 extend along conductive portion IIb. These flanges increase the distributed capacitance between portions I Ia, I Ib and decrease the inductane thereof to decrease the characteristic impedance Z2 of the second stub line. As a consequence, the characteristic impedances of the first and second stub lines are diiferent, the impedance of the second line being selected to compensate for impedance variations of the first stub line as well as the

dipole antenna

25, 26. More specifically, the characteristic impedance of the seconds'tub line Ila", IIb" is less than that of the first stub line Iib', I3 by an amount eflective to provide the-desired impedance compensation.

In Fig. 5 there is represented an end viewof the balanced-line section of a further modification of the Fig. 1 connector. The Fig.5 embodiment is generally similar to that of Fig. 4, difiering only in the manner. of loading the second stub line for improved wide-band operation in view of a. particular balanced-circuit. arrangement In the instant case the second stub line Ila", I Ib" is decreased bya first conductive element 23 extending along the length of conductive portion I la and curved around the alternate portion I lb. A similar conductive element 24 projects from portion IIb and extends around portion I Ia.

Elements

23 and 24 are proportioned to determine the characteristic impedance of the second stub line as required to effect the desired impedance compensation.

In the embodiments of Figs. 4 and 5 where the second stub line is constructed to compensate for impedance variations introduced by the balancedcircuit arrangement coupled to the connector, consideration was given to the case in which the balanced circuit is series-resonant at the mean operating wave length. For the alternate type of balanced circuit which is parallel-resonant at the mean wave length, a like impedance compensation may be achieved by constructing or loading the second stub line Ila", III)" to have a characteristic impedance which is greater than that of the first stub line I Ib, I3".

For some purposes, it may be desired to arrange the connector so that its first stub line I II), I3" has a high characteristic impedance. Such a construction is represented in Figs. 6 and 'Z. The connector is generally similar to that of Fig. 1 and corresponding components thereof are identified by like reference characters. In this embodiment, the second section I3 of the inner conductor has a hollow semi-circular cross section. The schematic circuit diagram of Fig. 3 also represents the electrical circuits included in the connector of Figs. 6 and 7. Likewise, the

views of Figs. 3a, 3b and 3d and the impedance notations associated therewith illustrate the counterparts of the electrical portions of Fig. 3 found in the mechanical construction of Fig. 6. The first stub line I lb, l3" of Fig. 3 is provided by the conductive portion Nb of the outer conductor and inner-conductor section I3 as shown in Fig. 8. These conductors have an impedance Z3, determined by their relative spacing, which is substantially greater than that of the balancedline portion Ila, I3.

In describing the illustrated circuit connectors, the diameters of the first and second sections of the inner and outer conductors have been said to be proportioned so that the balanced and unbalanced-line portions of the connector have substantially the same characteristic impedance. It will be understood that the relative diameters of the conductor sections establish the inter-ccnductor spacing and the impedance of the transmission lines. The spacing is always selected in view of the dielectric as well as the magnetic properties of the inter-conductor space and the region immediately outside the outer conductor. Where the coaxial conductors have anair separation, the spacing has a given value in order to obtain a desired impedance level. If some other substance having difierent dielectric and magnetic properties fills the space betwen the conductors, the spacing usually has a different value to establish the same impedance level for the line. The term "relative spacing" and similar expressions of the appended claims designate the conductor spacing in view of the line dielectric and similar factors. The balanced-line portion of the circuit connector may, if desired, have a different material in the inter-conductor space than the unbalancedline section. Where the materials filling the interconductcr spaces of the balanced and unbalanced-circuit portions have the proper relative dielectric and magnetic characteristics, each of the inner and outer conductors of the connector may have a uniform diameter while obtaining the desired impedance relationships.

Slots I I and I5 of the outer conductor are usually thin. That is, the slot width in practical cases is less than the radial clearance between the inner and outer conductors of the connectors.

While there have been described what are at present onsidered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

l. A balanced-to-unbalanced circuit connector comprising, an outer conductor includin a first section and a contiguous second section having a pair of longitudinal slots extending from one end of said outer conductor and forming in said second section a pair of conductive portions, an inner conductor including a first section and a contiguous second section coaxially supported within said first and second sections respectively of said outer conductor and connected to one of said conductive portions substantially at the free end thereof, said first sections of said inner and outer conductors having a relative spacing selected to provide an unbalanced transmission line having a predetermined characteristic impedance at a given operating wave length, and said second sections of said inner and outer conductors having a relative spacing selected so that said second section of said inner conductor and the other one of said pair of conductive portions provide a balanced transmission line having approximately said predetermined characteristic impedance.

2. A balanced-to-unbalanced circuit connector comprising, an outer conductor including a first section and a contiguous second section of a predetermined length having a pair of longitudinal slots extending from one end of said outer conductor andforming in said second section a pair of conductive portions, an inner conductor including a first section and a contiguous second section of said predetermined length coaxially supported within said first and second sections respectively of said outer conductor and connected to the free end of one of said conductive portions, said first sections of said inner and outer conductors having a relative spacing selected to provide an unbalanced transmission line having a predetermined characteristic impedance at a given operating wave length, and said second sections of said inner and outer conductors having a relative spacing selected so that said second section of said inner conductor and the other one of said pair of conductive portions prc vide a balanced transmission line having approximately said predetermined characteristic impedance.

3. A balanced-to-unbalanced circuit connector comprising, an outer cylindrical conductor including a first section and a contiguous second section having a pair of longitudinal slots extending from one end of said outer conductor and forming in said second section a. pair of conductive portions, an inner cylindrical conductor including a first section and a contiguous second section ccaxially supported within said first and second sections respectively of said outer conductor and connected to one of said conductive portions substantially at the free end thereof, said first sections of said inner and outer conductors having relative diameters selected to provide an unbalanced transmission line having a predetermined characteristic impedance at a, given operating wave length, and said second sections of said inner and outer conductors having relative diameters selected so that said second section of said inner conductor and the other one of said pair of conductive portions provide a balanced transmission line having approximately said predetermined characteristic impedance.

4. A balanced-to-unbalanced circuit connector comprising, an outer cylindrical conductor of substantially uniform diameter including a first section and a contiguous second section having a pair of longitudinal slots extending from one end of said outer conductor and forming in said second section a pair of conductive portions, an inner cylindrical conductor including a first section and a contiguous second section coaxially supported within said first and second sections respectively of said outer conductor and connected to one of said conductive portions substantially at the free end thereof, said first section of said inner conductor having a diameter selected with reference to the diameter of said outer conductor so that said first sections of said inner and outer conductors provide an unbalanced transmission line having a predetermined characteristic impedance at a given operating wave length, said second section of said inner conductor having a diameter selected with reference to the diameter of said outer conductor so that said second section of said inner conductor and the other one of said pair of conductive portions provide a balanced transmission line having approximately said predetermined characteristic impedance.

5. A balanced-to-unbalanced circuit connector comprising, an outer cylindrical conductor of circular cross section and substantially uniform diameter including a first section and a contiguous second section having a pair of longitudinal slots extending from one end of said outer conductor and forming in said second section a pair of conductive portions, an inner cylindrical conductor of circular cross section including a first section and a contiguous second section coaxially supported'within said first and second sections respectively of said outer conductor and separated therefrom by a homogeneous dielectric, means for connecting said inner conductor to one of said conductive portions substantially at the free end thereof, said first section of said inner conductor having a diameter selected with reference to the diameter of said outer conductor so that said first sections of said inner and outer conductors provide an unbalanced transmission line having a predetermined characteristic impedance at a given operating wave length, said second section of said inner conductor having a diameter substantlally equal to the geometric mean of the diameters of said first sections of said inner and outer conductors so that said second section of said inner conductor and the other one of said pair of conductive portions provide a balanced transmission line having approximately said predetermined characteristic impedance.

6. A balanced-to-unbalanced circuit connector comprising, an outer cylindricalconductor or circular cross section including a first section and a contiguous second section having a pair of diametrically opposed longitudinal slots extending ed to provide an unbalanced transmission line having a predetermined characteristic impedance at a, given operating wave length, and said second sections of said inner and outer conductors having relative diameters selected so that said second section of said inner conductor and the other one of said pair of conductive portions provide a balanced transmission line having approximately said predetermined characteristic impedance.

7. A balanced-to-unbalanced circuit connector comprising, an outer conductor including a first section and a, contiguous second section having a pair of longitudinal slots extending from one end of said outer conductor and formin in said second section a pair of conductive portions, an inner conductor including a first section and a contiguous second section coaxially supported within said first and second sections respectively of said outer conductor, conductive means for connecting the free end of said second section of said inner conductor to the corresponding end of one of said conductive portions, said first sections of said inner and outer conductors having a relative spacing selected to provide an unbalanced tranmission line having a predetermined characteristic impedance at a given operating wave length, and said second sections of said inner and outer conductors having a lected so that said second section of said inner conductor and the other one of said pair of conductive portions provide a balanced transmission line having approximately said predetermined characteristic impedance.

8. A balanced-to-unbalanced circuit connector comprising, an outer conductor including a first section and a contiguous second section having a pair of longitudinal slots extending from one end of said outer conductor and forming in said second section a pair of conductive portions, and an inner conductor including a first section and a contiguous second section coaxially supported within said first and second sections respectively of said outer conductor, conductive means for supporting and for connecting the free end of said second section of said inner conductor to the corresponding end of one of said conductive portions, said first sections of said inner and outer I conductors having a relative spacing selected to provide an unbalanced transmission line, having a predetermined characteristic impedance at a given operating wave length, and said .second sections of said inner and outer conductors having a relative spacing selected so that said second section of said inner conductor and the other one of said pair of conductive portions provide a balanced transmission line having approximately said predetermined characteristic impedance.

9. A balanced-to-unbalanced circuit connector comprising, an outer conductor including a first section and a contiguous secondsection having a pair of longitudinal slots extending from one end of said outer conductor and forming in said second section a pair of conductive portions individually having an eirective electrical length aprelative spacing seproximately equal to one-quarter of a given operating wave length, an inner conductor including a first section and a, contiguous second section coaxially supported within said first and second sections respectively of said outer conductor, said second section of said inner conductor having an efiective electrical length approximately equal to one-quarter of said wave length and being connected to One of said conductive portions substantially at the free end thereof, said first sections of said inner and outer conductors having a relative spacing selected to provide an unbalanced transmission line having a predetermined characteristic impedance at Said wave length, and said second sections of said inner and outer conductors having a relative spacing selected so that said second section of said inner conductor and the other one of said pair of conductive portions provide a balanced transmission line having approximately said predetermined characteristic impedance.

10. A balanced-to-unbalanced circuit connector comprising, an outer conductor including a first section and a contiguous second section having a pair of longitudinal slots extending from one end of said outer conductor and forming in said second section a pair of conductive portions individually having an effective electrical length equal to one-quarter of a given operating wave length, means adjacent to said conductive portions for determining the characteristic impedance therebetween, an inner conductor including a first section and a contiguous second section having an effective electrical length equal to one-quarter of said wave length coaxially supported within said first and second sections respectively of said outer conductor and connected to one of said conductive portions substantially at the free and thereof, said first sections of said inner and outer conductors having a relative spacing selected to provide an unbalanced transmission line having a predetermined characteristic impedance at said wave length, and said second sections of said inner and outer conductors having a relative spacing selected so that said second section of said inner conductor and the other one of said pair of conductive portions provide a balanced transmission line having approximately said predetermined characteristic impedance.

11. A balanced-to-unbalanced circuit connector comprising, an outer conductor including a first section and a'contiguous second section having a pair of longitudinal slots extending from one end of said outer conductor and forming in said second section a pair of conductive portions individually having an effective electrical length equal to one-quarter of a given operating wave length, flange members extending from said conductive portions along the length of said slots for decreasing the characteristic impedance therebetween, an inner conductor including a first section and a contiguous second section having an effective electrical length equal to onequarter of said wave length coaxially supported within said first and second sections respectively of said outer conductor and connected to one of said conductive portions substantially at the free end thereof, said first sections of said inner and outer conductors having a relative spacing selected to provide an unbalanced transmission line having a. predetermined characteristic impedance at said wave length, and said second sections of said inner and outer conductors having a relative spacing selected so that said second section of said inner conductor and the other one of said pair of conductive portions provide a balanced transmission line having approximately said predetermined characteristic impedance. A

12. A balanced-to-unbalanced circuit connector for operation over a wide range of wave lengths comprising, an outer conductor including a first section and a contiguous second section having a pair of longitudinal slots extending from one end of said outer conductor and forming in said second section a pair of conductive portions individually having an effective electrical length approximately equal to one-quarter of the mean wave length of said range, an inner conductor including a first section and a contiguous second section coaxially supported within said first and second sections respectively of said outer conductor, said second section of said inner conductor having an effective electrical length approximately equal to one-quarter of said mean wave length and being connected to one of said conductive portions substantially at the free end thereof, said first sections of said inner and outer conductors having a relative spacing selected to provide an unbalanced transmission line having a predetermined characteristic impedance at said mean wave length, said second sections of said inner and outer conductors having a relative spacing selected so that said second section of said inner conductor and the other one of said pair of conductive portions provide a balanced transmission line having approximately said predetermined characteristic impedance, and said slots having such width that said conductive portions of said outer conductor provide a stub line having a characteristic impedance substantially equal to that of an additional stub line formed by said second section of said inner conductor and said one conductive portion of said outer conductor.

13. A balanced-to-unbalanced circuit connector for operation over a wide range of wave lengths and for connection with a balanced circuit arrangement which is resonant at the mean wave length of said range comprising, an outer conance therebetween, an inner conductor including a first section and a contiguous second section coaxially supported within said first and second sections respectively of said outer conductor, said second section of said inner conductor having an effective electrical length approximately equal to one-quarter of said mean wave length and being connected to one of said conductive portions substantially at the free end thereof, said first sections of said inner and outer conductors having a relative spacing selected to provide an unbalanced transmission line having a predetermined characteristic impedance at said mean wave length, said second sections or said inner and outer conductors having a relative spacing selected so that said second section of said inner conductor and the other one of said pair of conductive portions provide a balanced transmission line having approximately said predetermined characteristic impedance, and said loading means being so selected that said conductive portions of said outer conductor provide a stub line having a characteristic impedance different from that of an additional stub line formed by said second section of said inner conductor and said one conductive portion of said outer conductor and effective substantially to compensate the impedance variations of said balanced circuit arrangement and said additional stub line over said range of wave lengths.

14. A balanced-to-unbalanced circuit connector for operation over a wide range of wave lengths and for connection with a balanced circuit arrangement which is series-resonant at the mean wave length of said range comprising, an outer conductor including a first section and a contiguous second section having a pair of longitudinal slots extending from one end of said outer conductor and forming in said second section a pair of conductive portions individually having an efiect ve electrical length approximately equal to one-quarter of the mean wave length of said range, loading means adjacent to said conductive portions for determining the characteristic impedance therebetween, an inner conductor including a, first section and a contiguous second section coaxially supported within said first and second sections respectively of said outer conductor, said second section of said inner conductor having an efiective electrical length approximately equal to one-quarter of said mean wave length and being connected to one of said conductive portions substantially at the free end thereof, said first sections of said inner and outer conductors having a relative spacing selected to provide an unbalanced transmission line having a predetermined characteristic impedance at said mean wave length, said second sections of said inner and outer conductors having a relative spacing selected so that said second section of said inner conductor and the other one of said pair of conductive portions provide a balanced transmission line having approximately said predetermined characteristic impedance, said loading means being so selected that said conductive portions of said outer conductor provide a stub line having a characteristic impedance less than that of an additional stub line formed by said second section of said inner conductor and said one conductive portion of said outer conductor and eflective substantially to compensate the impedance variations of said balancedvcircuit arrangement and said additional stub line over said range of wave lengths.

15. A balanced-to-unbalanced circuit connector comprising, an outer conductor including a first section and a contiguous second section having av pair of longitudinal slots extending from one end of said outer conductor and forming in said second section a pair of conductive portions, an inner conductor including a first section and a contiguous second section coaxiaily supported within said first and second sections respectively of said outer conductor and connected to one of said conductive portions substantially at the free end thereof, said first sections of saidinner and outer conductors having a relative spacing selected to provide an unbalanced transmission line having a predetermined characteristic impedance at a given operating wave length, said second section of said inner conductor and th other one of said pair of conductive portions having a relative spacing selected to provide a balanced transmission line having approximately said predetermined characteristic impedance, and said second section of said inner conductor and said one conductive portion having a relative spacing selected to provide 'a stub line connected to but having a substantially greater characteristic impedance than said balanced line.

HAROLD A. WHEEIER.