CN114464422A - Transmission line transformer with non-integer square transformation ratio - Google Patents

Abstract

The invention discloses a transmission line transformer with non-integer square transformation ratio, which comprises an impedance transformation ratio of 1: N²The winding type transformer T1 and the melon pull type transformer T2 with the impedance transformation ratio of 4:1, N is an integer more than or equal to 2; the winding transformer T1 and the melon pull-in transformer T2 are both provided with a low impedance port and a high impedance port; the low-impedance port of the winding transformer T1 is connected in parallel with the high-impedance port of the melon pull-in transformer T2 to form a total outward low-impedance port of the transmission line transformer; winding formula transformer T1's high impedance port with draw formula transformer T2's low impedance port is established ties in the melon, forms after establishing ties the general external high impedance port of transmission line transformer. The invention can realize

The non-integer-square impedance ratio-change transformer of (2),the impedance transformation ratio step is thinned, single-ended-differential (balanced) impedance transformation can be realized, the structure volume is compact, and the impedance transformation ratio switching is flexible.

Description

Transmission line transformer with non-integer square transformation ratio

[ technical field ] A method for producing a semiconductor device

The invention belongs to the technical field of radio frequency circuits, and particularly relates to a transmission line transformer with a non-integer square transformation ratio.

[ background of the invention ]

The transmission line transformer has the advantages of wide bandwidth, simple structure and low cost, and is widely applied to short-wave and ultra-short-wave radio frequency circuits. By selecting the power capacity of the transmission line, larger power passing capacity can be obtained, and the power transmission line is particularly suitable for being used as an impedance converter of a high-power amplifier.

Common transmission transformers are in the form of rutherff (Ruthoff), Guanella (Guanella), and wound (Toroid), as shown in fig. 1 to 4. The core structure constituting the above-described transformer is a radio frequency transmission line, such as a twisted pair or a coaxial line. Generally, two conductors of a transmission line are equal in length and appear in pairs, and the transmission line has the advantages that the distributed capacitance and the inductance between the conductors form a transmission line effect, the transmission line has good broadband characteristics, meanwhile, electromagnetic field energy is distributed between the two conductors, the field intensity outside the transmission line is weak, the transmission line is particularly important for low-frequency applications needing magnetic materials such as short-wave and ultra-short wave frequency bands, the requirements on the magnetic saturation intensity and the loss of the materials can be greatly reduced, and the transmission line is particularly suitable for low-frequency high-power applications. The typical implementation of the winding (Toroid) type is shown in fig. 4, and its low impedance port is a differential balanced port, presents high impedance to ground, has a common mode isolation effect, and is particularly suitable for use in a push-pull circuit.

Because the number of the transmission line segments is N (N is more than or equal to 1) which is an integer, the impedance transformation ratio which can be realized is N ²1, namely 1:1, 4:1, 9:1 and the like, has large transformation ratio span step pitch, and cannot meet the requirement of optimizing the performance of the high-power amplifier. In recent years, the miniaturization requirement of communication electronic equipment is higher and higher, and a high-power amplifier has high power consumption and large requirement on heat dissipation space, and is an important point and difficulty for miniaturization. The volume of the power amplifier is reduced, on one hand, the power amplifier needs to be supported by a device with high power density, on the other hand, an external matching circuit is matched, and balanced optimization is carried out on the two aspects of efficiency and linearity. If the impedance transformation ratio step is too large, the impedance fine adjustment cannot be realized, and the requirement of performance optimization cannot be met.

In order to refine the impedance transformation ratio, fig. 5 and 6 illustrate two transformer topologies with non-integer transformation ratio based on the melon pull type principle. Wherein the transformers shown in FIG. 5 are commonIncluding 3 coaxial cables 21 ', 22 ' and 23 '. On the side of port 24 ', cables 21' and 22 'are connected in parallel and then in series with cable 23'. On the side of port 25 ', cable 21' is connected in series with cable 22 'and then in parallel with cable 23'. If a load with impedance Z is connected to the side of the port 25 ', the equivalent input impedance of the port 24' is 1.5²Z, impedance transformation ratio is 2.25 times. A 9:1 impedance transformation ratio can also be achieved with three coaxial cables.

Fig. 6 shows 4 coaxial cables 31 'to 34', where the cables 31 'and 32' are connected in parallel and then connected in series with 33 'on the side of the port 35', the three cables are connected in parallel with 34 'as one unit, and the cable 31' is connected in series with 32 'first, then connected in parallel with the cable 33' as one unit and finally connected in series with the cable 34 'as one unit on the side of the port 36'. When port 35 'is connected to a load having an impedance Z, port 36' has an input impedance of

The adoption of 4 coaxial cables can also realize

And a 16:1 ratio.

The non-integer square transformation ratio transformer can meet the requirement of thinned impedance transformation ratio in principle, but because insulation isolation is required among cables, in the application of lower frequency and longer wavelength (such as short wave band), each section of cable is longer and needs to be wound into a spiral assembly, and the turn-to-turn distance is as large as possible to reduce the distributed capacitance, so that the volume of the transformer is larger, the implementation difficulty of miniaturization engineering is brought, and the transformer is generally used in an ultra-short wave band with relatively higher frequency.

In addition, the melon pull-in transformer is mostly directly used for impedance conversion from a single end to a single end, and a high-power amplifier generally adopts a push-pull circuit, and needs the conversion from the single end to a difference (or push-pull), so as to better realize ground isolation, a section of BALUN (BALUN) is also needed to be added, and the volume of an impedance conversion part is further increased.

The outer conductors of the different cable sections of the wound transformer shown in fig. 4 are in close electrical contact, single-ended to differential impedance conversion can be realized without an external balun, and the wound transformer is compact in structure, so that the wound transformer is particularly suitable for short-wave and other low-frequency applications. However, the operation principle is different from the circuits shown in fig. 5 and 6, and therefore, the non-integer square transformation ratio cannot be realized by directly applying the principle.

Another scheme for realizing the non-integer square transformation ratio is disclosed in chinese patent publication CN109754989A, and the principle is to lengthen the length of the conductor of the high-impedance winding, so that the number of turns of the high-impedance winding is (2+1/2) turns, thereby realizing the impedance transformation ratio of 6.25: 1. The method causes the length of two conductors of the transmission line to be inconsistent, destroys the basic mode of the transmission line transformer, forms stronger induction magnetic flux in the external space, easily causes the magnetic saturation of the magnetic material when the passing power is larger, and the loss of the magnetic material also causes the magnetic core to generate heat, has high transmission loss, and is not suitable for high-power application.

At present, no transmission line transformer with compact volume and non-integer square transformation ratio suitable for high-power application exists in a short-wave frequency band. Therefore, there is a need to provide a new transmission line transformer with non-integer square transformation ratio to solve the above technical problems.

[ summary of the invention ]

The invention mainly aims to provide a transmission line transformer with non-integer square transformation ratio, which overcomes the defects of large volume, difficulty in miniaturization and high loss of a short-wave frequency band non-integer square transformation ratio transmission line transformer.

The invention realizes the purpose through the following technical scheme: a transmission line transformer with non-integer square transformation ratio comprises an impedance transformation ratio of 1: N²Winding type transformer T1 and melon pull-in type transformer T2 with impedance transformation ratio of 4:1, N is an integer more than or equal to 2; the winding transformer T1 and the melon pull-in transformer T2 are both provided with a low impedance port and a high impedance port; the low-impedance port of the winding transformer T1 is connected in parallel with the high-impedance port of the melon pull-in transformer T2 to form a total outward low-impedance port of the transmission line transformer; the high-impedance port of the winding transformer T1 is connected in series with the low-impedance port of the melon pull-in transformer T2And the transmission line transformers are connected in series to form a total external high-impedance port of the transmission line transformer.

Furthermore, the low impedance port of the winding transformer T1 is composed of a low impedance terminal e and a low impedance terminal f;

the high-impedance port of the winding type transformer T1 is composed of a high-impedance terminal g and a high-impedance terminal h;

the low impedance terminal e of the winding transformer T1 is in phase with the high impedance terminal g;

the low-impedance port of the melon pull-in transformer T2 is composed of a low-impedance terminal i and a low-impedance terminal j;

the low-impedance port of the melon pull-in transformer T2 is composed of a high-impedance terminal k and a high-impedance terminal m;

the low impedance terminal i of the melon pull-in transformer T2 is in phase with the high impedance terminal k.

Further, the high-impedance port of the winding transformer T1 and the low-impedance port of the melon pull-in transformer T2 are connected in series in a first series manner

The impedance transformation ratio of (1); the first series connection mode is as follows: the low impedance terminal i of T2 is connected with the high impedance terminal h of T1, and the low impedance terminal j of T2 is grounded; or

The high-impedance port of the winding transformer T1 and the low-impedance port of the melon inner pull type transformer T2 are connected in series in a second series connection mode to realize

The impedance transformation ratio of (1); the second series connection mode is as follows: the low impedance terminal j of T2 is connected to the high impedance terminal h of T1, and the low impedance terminal i of T2 is grounded.

Further, the wound transformer T1 includes N transmission lines TL₁～TL_N(ii) a Each segment of the transmission line comprises a conductor R1 and a conductor R2 which are equal in length; the conductors R1 in the N-section transmission lines are sequentially connected in series end to end, and the transmission line TL₁The starting terminal of (A) constitutes the high impedance terminal g, TL of T1_NThe terminal of (A) constitutes the high resistance of T1A resistance terminal h; one end of a conductor R2 in the N-segment transmission line is connected in parallel to form a low-impedance terminal e of the T1, the other end of the conductor R2 is connected in parallel to form a low-impedance terminal f of the T1, and the central points of all conductors R2 are grounded.

Furthermore, the melon pull-in transformer T2 comprises two sections of transmission lines TL with equal length_N+1And TL_N+2(ii) a Each segment of the transmission line comprises conductors R3 and R4 with equal length; transmission line TL_N+1One end of the conductor R3 and the transmission line TL_N+2One end of the conductor R4 in the T2 is connected in parallel to form a low-impedance terminal i of a transmission line TL_N+1One end of the conductor R4 and the transmission line TL_N+2One end of the conductor R3 in the T2 is connected in parallel to form a low impedance terminal j; transmission line TL_N+1The other end of the conductor R3 forms the high impedance terminal k of T2, the transmission line TL_N+1The other end of the middle conductor R4 and the transmission line TL_N+2The other end of the middle conductor R3 is connected to the transmission line TL_N+2The other end of the conductor R4 in (1) constitutes a high impedance terminal m of T2.

Further, the winding transformer T1 includes N-1 "U" shaped coaxial cables and two straight coaxial cables; the N-1U-shaped coaxial cables are stacked in parallel and the outer conductors of the U-shaped coaxial cables are in close contact to form a U-shaped cable cluster, wherein a first straight coaxial cable is tightly attached to a straight edge on one side of the U-shaped cable cluster from the lower side in parallel, a second straight coaxial cable is tightly attached to a straight edge on the opposite side of the U-shaped cable cluster from the upper side in parallel, and the outer conductors of the two straight coaxial cables are in close contact with the outer conductor of the U-shaped cable cluster;

at the opening end of the U-shaped cable cluster, an inner conductor of a first straight coaxial cable is connected with an inner conductor of the opposite side straight edge of the lowest U-shaped coaxial cable in the U-shaped cable cluster, an inner conductor of the same side straight edge of the U-shaped coaxial cable is connected with an inner conductor of the opposite side straight edge of the U-shaped coaxial cable in the previous layer, and the U-shaped coaxial cable is pushed up layer by layer until the top layer is reached; the straight-side inner conductor of the U-shaped coaxial cable on the same side of the topmost layer is connected with the inner conductor of the second straight coaxial cable on the opposite side;

in the U-shaped cable cluster, the straight-side outer conductors of the U-shaped coaxial cables on the same side as the second straight coaxial cable are integrally connected to form a low-impedance terminal e of T1, and the straight-side outer conductors of the U-shaped coaxial cables on the same side as the first straight coaxial cable are integrally connected to form a low-impedance terminal f of T1; one end of the inner conductor of the first straight coaxial cable, which is close to the arc section of the U-shaped coaxial cable, forms a high-impedance terminal g of T1, and one end of the inner conductor of the second straight coaxial cable, which is close to the arc section of the U-shaped coaxial cable, forms a high-impedance terminal h of T1; the outer conductors of the "U" shaped cable cluster are integrally connected together at the arcuate segments and grounded.

Furthermore, the melon inner pull type transformer T2 is positioned above the winding type transformer T1, and except for the connection between terminals, two sections of transmission lines TL T2_N+1And TL_N+2All of the conductors of (a) are not in contact with T1; the high impedance port of T2 is located on the open side of the "U" shaped cable cluster of T1 and the low impedance port of T2 is located on the arcuate end side of the "U" shaped cable cluster of T1.

Furthermore, draw formula transformer T2's transmission line TL in melon_N+1And TL_N+2Is a coaxial cable; in the two sections of the transmission line,

the inner conductor of the coaxial cable is the conductor R3, and the outer conductor is the conductor R4; or

The outer conductor of the coaxial cable is the conductor R3, and the inner conductor is the conductor R4.

Further, the melon inner pull type transformer T2 further includes an independent wire, and the length of the independent wire is the same as the length of the transmission line in the melon inner pull type transformer T2;

in the first series mode, one end of the independent wire is connected with a high-impedance terminal k of T2, and the other end of the independent wire is connected with a low-impedance terminal j of T2 and grounded;

in the second series connection, one end of the individual wire is connected to the high impedance terminal m of T2, and the other end is connected to the low impedance terminal i of T2 and grounded.

Further, the magnetic core comprises at least two through rectangular holes and at least two through circular holes; one is correspondingly arranged above each rectangular holeEach of the circular holes; the U-shaped cable cluster of the winding type transformer T1 and the first and second straight coaxial cables are arranged in the rectangular hole, and the open end and the arc end of the U-shaped cable cluster are connected with corresponding conductors outside the magnetic core; transmission line TL of melon inner pull type transformer T2_N+1And TL_N+2Located in two of the circular holes, respectively, transmission lines TL_N+1And TL_N+2The two ends of the magnetic core extend out of the magnetic core and are connected with corresponding conductors.

Further, the melon inner pull type transformer T2 further includes an independent wire, and the length of the independent wire is the same as the length of the transmission line in the melon inner pull type transformer T2;

in the first series mode, one end of the independent wire is connected with a high-impedance terminal k of T2, and the other end of the independent wire is connected with a low-impedance terminal j of T2 and grounded;

in the second series connection mode, one end of the independent wire is connected with the high-impedance terminal m of T2, and the other end is connected with the low-impedance terminal i of T2 and grounded;

the circular port has set gradually three side by side, independent wire setting is in middle circular port.

Compared with the prior art, the transmission line transformer with the non-integer square transformation ratio has the beneficial effects that: the impedance transformation ratio has the characteristics of compact structure, simplicity in implementation, flexibility in impedance transformation ratio change and the like. Specifically, the winding type transformer and the melon inner pull type transformer are combined, the winding type transformer realizes the impedance transformation of an integer part and the single-end-differential conversion, the melon inner pull type transformer completes the non-integer transformation ratio, the compact structure is ensured, the single-end-differential (balanced) impedance transformation can be realized, and the melon inner pull type transformer has the advantages of

The step pitch of the impedance transformation ratio is thinned by the non-integer square transformation ratio of (2); in addition, the series connection wire sequence of the high-resistance port of the winding type transformer and the low-resistance port of the melon pull-in type transformer is changed, so that the winding type transformer can be conveniently and flexibly realized

And

switching of transformation ratio; the scheme is particularly suitable for the miniaturization design of the short-wave high-power amplifier and the optimization of performance indexes; because two conductors in the transmission line that two transformers adopted in this scheme keep length the same throughout, transmission line outside magnetic field intensity is offset, after shortwave or ultrashort wave frequency channel introduce the magnetic core, to magnetic saturation intensity and the loss characteristic requirement greatly reduced of magnetic material, can not lead to the loss to increase because of magnetic material's introduction, and then solved the high problem of loss.

[ description of the drawings ]

FIG. 1 is a schematic diagram of a prior art Raseph-type transformer;

fig. 2 is a schematic diagram of a melon pull-in transformer in the prior art;

FIG. 3 is a schematic diagram of a prior art wound transformer;

FIG. 4 is a schematic diagram of a typical prior art implementation of a wound transformer;

fig. 5 is a schematic diagram of a 2.25:1 transformer based on the principle of melon pull in the prior art;

fig. 6 is a principle of melon pulling in the prior art

A schematic diagram of a transformer;

FIG. 7 is a block diagram of a first embodiment of the present invention;

FIG. 8 is a schematic diagram of a first serial connection in accordance with a first embodiment of the present invention;

FIG. 9 is a schematic diagram of a second series arrangement in accordance with a first embodiment of the present invention;

fig. 10 is a schematic structural diagram of an implementation of the first scheme in the first embodiment of the present invention;

fig. 11 is a schematic structural diagram of an implementation of the second scheme in the first embodiment of the present invention;

fig. 12 is a schematic structural diagram of an implementation of the third aspect in the first embodiment of the present invention;

fig. 13 is a schematic structural diagram of an implementation of a fourth scheme in the first embodiment of the present invention;

FIG. 14 is a schematic structural diagram of an implementation of a second embodiment of the present invention;

FIG. 15 is a schematic diagram of a magnetic core structure according to a third embodiment of the present invention;

FIG. 16 is an open end view of a "U" shaped cable cluster according to a third embodiment of the present invention;

FIG. 17 is a view of an arc segment of a "U" -shaped cable cluster according to a third embodiment of the present invention;

FIG. 18 is a side view of a third embodiment of the present invention;

FIG. 19 is the real part frequency response of the differential mode impedance of the third embodiment of the present invention;

FIG. 20 is the imaginary frequency response of the differential mode impedance of example three of the present invention;

fig. 21 shows the amplitude frequency response of the common mode impedance according to the third embodiment of the present invention.

[ detailed description ] embodiments

The first embodiment is as follows:

this embodiment is a transmission line transformer with non-integer square transformation ratio, as shown in FIG. 7, which includes an impedance transformation ratio of 1: N²A winding transformer T1 (N is an integer of 2 or more) and a melon inner pull type transformer T2 having an impedance transformation ratio of 4: 1. The low impedance port 11 of the T1 is connected in parallel with the high impedance port 21 of the transformer T2, and after parallel connection, an external low impedance terminal a and an external low impedance terminal b of the non-integer square transformation ratio transformer are formed, and an external low impedance port is formed between the external low impedance terminal a and the external low impedance terminal b. The high impedance port 12 of the T1 is connected in series with the low impedance port 22 of the T2, and after being connected in series, the total external high impedance terminal c and the external high impedance terminal d of the non-integer square ratio transformer are formed, and the external high impedance port is formed between the external high impedance terminal c and the external high impedance terminal d.

The principle of an embodiment of the invention is shown in fig. 8 and 9.

In which the wound transformer T1 consists of N transmission lines TL₁～TL_NAnd (4) forming. Each transmission line segment includes two equal length conductors, conductor R1 and conductor R2. TL₁～TL_NThe N sections of conductors R1 are connected in series end to end in sequence, TL₁The starting end 1311 of the conductor R1 forms the high impedance terminal g, TL of the wound transformer T1_NThe terminal end 1312 of the conductor R1 forms the high impedance terminal h of the wound transformer T1. The first ends 1321 of all the N-segment conductors R2 are connected in parallel together as the low impedance terminal e of the winding transformer T1, and the second ends 1322 of all the N-segment conductors R2 are connected in parallel together as the low impedance terminal f of the winding transformer T1. The center points of all conductors R2 are grounded. The low impedance terminal e and the low impedance terminal f form a low impedance port 11 of T1, and the high impedance terminal g and the high impedance terminal h form a high impedance port 12 of T1.

The melon pull-in transformer T2 is composed of two sections of transmission lines TL with equal length_N+1And TL_N+2And (4) forming. Each transmission line segment includes conductors R3 and R4 of equal length. At TL_N+1And TL_N+2At one end (right side of T2 in the figure), TL_N+1Conductor R3 and TL_N+2Is connected in parallel to form a low impedance terminal i, TL of T2_N+1Conductor R4 and TL_N+2Is connected in parallel to form a low impedance terminal j of T2; at TL_N+1And TL_N+2At the other end (left side of T2 in the figure), TL_N+1Conductor R3 as the high impedance terminal k, TL of T2_N+1Conductor R4 and TL_N+2Is connected to conductor R3, TL_N+2The conductor R4 of (a) serves as the high impedance terminal m of T2. The low impedance terminal i and the low impedance terminal j form a low impedance port 21 of T2, and the high impedance terminal k and the high impedance terminal m form a high impedance port 22 of T2.

The low impedance terminals e and f of the winding transformer T1 are connected in parallel with the high impedance terminals k and m of the melon pull-in transformer T2, so that the low impedance port 11 and the high impedance port 22 are connected in parallel.

In fig. 8, the low impedance port 21 of T2 and the high impedance port 12 of T1 are connected in a first series, i.e., the low impedance terminal i of T2 is connected to the high impedance terminal h of T1, and the low impedance terminal j of T2 is grounded, so as to implement

The impedance transformation ratio of (1). The principle is as follows:

if the voltages to the external low-resistance terminals a and b of the non-integer-square-ratio transformer are + V/2 and-V/2, respectively, the voltage to the ground at the low-resistance terminal i of T2 is + V/2. The first terminal 1321 of all conductors R2 of T1 is + V/2 ground and the second terminal 1322 is-V/2 ground. From TL_NThe terminal 1312 of the conductor R1 in the transmission line starts each time it passes through a section TL of the transmission line_iThen the voltage at the beginning of conductor R1 increases by V, eventually to ground at the T1 high impedance terminal g

I.e. the voltage to ground of the transformer's overall external high resistance terminal c.

If the total external high-impedance terminal c of the non-integer-square-ratio transformer has an outward current I, the currents of all the conductors R1 of the winding transformer T1 are I, and the current at the high-impedance terminal h of T1 is also I and flows into the high-impedance terminal h. The magnitude of the current on all conductors R2 of T1 is also I, and the direction is from the first terminal 1321 to the second terminal 1322, then the magnitude of the current at the low impedance terminal e of T1 is NI, and the direction is to flow into the low impedance terminal e. At the high impedance terminal g of T1, the current magnitude is I/2 and the direction is into the high impedance terminal g. Therefore, at the total external high-resistance terminals c and d of the non-integer square ratio transformer, the current amplitude is

The direction flows into the external high-resistance terminal c and flows out of the external high-resistance terminal d.

If the load impedance of the total external high-resistance terminal c to the ground is Z, the following conditions are satisfied:

at the total external low impedance port, the equivalent input impedance is:

the high and low impedance transformation ratios are therefore:

referring to fig. 9, the low impedance port 21 of T2 and the high impedance port 12 of T1 shown in fig. 9 are connected in a second series manner, i.e., the low impedance terminal j of the melon pull-in transformer T2 is connected to the high impedance terminal h of T1, and the low impedance terminal i of T2 is grounded, so as to implement the connection

The impedance transformation ratio of (1). The principle is similar to the first series arrangement, except that the voltage to ground at the low impedance terminal j of T2 (i.e., at the high impedance terminal h of T1) is-V/2; the magnitude of the current at the high impedance terminal k of T2 is I/2 and the direction is the direction out of the high impedance terminal k, resulting in the sign of the final 1/2 transformation ratio term becoming negative.

Based on the above principle, the schematic implementation structure of the present embodiment is shown in fig. 10 to 13, and includes a winding transformer T1 and a melon pull transformer T2.

The wound transformer T1 of the present embodiment includes N-1 "U" shaped coaxial cables 511 and 2 straight coaxial cables 512 and 513. N-1U-shaped coaxial cables 512 are arranged in parallel in a stacking mode, and the outer conductors of two adjacent U-shaped coaxial cables 512 are in close contact with each other to form a U-shaped cable cluster together. In this embodiment, a first straight coaxial cable 512 is laid parallel and closely adjacent to the right (when viewed from the open end) straight edge of the "U" shaped cable cluster from below, and a second straight coaxial cable 513 is laid parallel and closely adjacent to the left straight edge of the "U" shaped cable cluster from above. The outer conductors of the two straight coaxial cables are both in close contact with the outer conductor of the U-shaped cable cluster. At the open end of the U-shaped cable cluster, one end 5121 of the inner conductor of the first straight coaxial cable 512 is connected with the inner conductor 5111 at the left straight edge of the lowest U-shaped coaxial cable, and the inner conductor 5112 at the right straight edge of the U-shaped cable is connected with the inner conductor 5113 at the left straight edge of the U-shaped coaxial cable at the previous layer, and pushed up layer by layer until reaching the topmost layer. The right straight inner conductor 5114 of the topmost "U" shaped coaxial cable is connected to the inner conductor end 5131 of the second straight coaxial cable 513 on the left. At the opening end of the U-shaped cable cluster, the outer conductors 514 and 515 of the two straight sides of the U-shaped coaxial cable are respectively used as a low-impedance terminal e and a low-impedance terminal f of the T1 to form a differential low-impedance port; in the arc section of the "U" -shaped cable cluster, the outer conductor 516 of the "U" -shaped cable cluster is grounded, the other end 5122 of the inner conductor of the first straight coaxial cable 512 serves as the high impedance terminal g of the high impedance port of the wound transformer T1, and the other end 5132 of the inner conductor of the second straight coaxial cable 513 serves as the other high impedance terminal h of the high impedance port of the wound transformer T1.

In a first embodiment of this embodiment, as shown in fig. 10, a bidirectional transformer T2 is composed of two straight coaxial cables 521 and 522. When viewed from the opening end of the U-shaped cable cluster, the straight coaxial cable 521 is placed above the straight edge on the right side of the U-shaped cable cluster in parallel; the straight coaxial cable 522 is parallelly arranged above the straight edge on the left side of the U-shaped cable cluster; the outer conductors of the straight coaxial cables 521 and 522 do not contact the outer conductor of the "U" shaped cable cluster.

In the embodiment of the present embodiment, the outer conductor of the coaxial cable is defined as the conductor R1 or the conductor R3, and the inner conductor is defined as the conductor R2 or the conductor R4, according to the principle of fig. 8, the inner conductor end 5211 of the straight coaxial cable 521 and the inner conductor end 5221 of the straight coaxial cable 522 are connected to each other, and the outer conductor end 5222 of the straight coaxial cable 522 and the outer conductor end 5212 of the straight coaxial cable 521 are respectively used as the high-impedance terminal k and the high-impedance terminal m of the T2, so as to form a high-impedance port of the T2. In the arc segment of the "U" shaped cable cluster, the other end 5223 of the inner conductor of the straight coaxial cable 522 is connected to the other end 5214 of the outer conductor of the straight coaxial cable 521 as the low impedance terminal j of T2; the other end 5213 of the inner conductor of the straight coaxial cable 521 is connected to the other end 5224 of the outer conductor of the straight coaxial cable 522, and serves as a low impedance terminal i of T2, and the low impedance terminal j and the low impedance terminal i constitute a low impedance port of T2.

The embodiment scheme of fig. 10 uses a first series arrangement, i.e., low impedance terminal i of T2 is connected to high impedance terminal h of T1, and low impedance terminal j of T2 is connected to the outer conductor 516 of the arc segment of the "U" shaped cable cluster to achieve ground.

The transformer is generally outwardThe low-resistance terminal is an external low-resistance terminal a which is directly led out from a low-impedance terminal e of T1, an external low-resistance terminal b is directly led out from a low-impedance terminal f of T1, and a total external high-resistance terminal c of the transformer is directly led out from a high-impedance terminal g of T1. The scheme of the embodiment can be realized (N +1/2)²1 impedance transformation ratio.

A second solution of the embodiment of the present invention is shown in fig. 11, which is different from the solution of fig. 10 in that a second series connection manner is adopted, that is, a low impedance terminal j of a melon pull-in transformer T2 (i.e., the other end 5214 of the outer conductor of the straight coaxial cable 521) is connected with a high impedance terminal h of a winding transformer T1 (i.e., the other end 5132 of the inner conductor of the second straight coaxial cable 513); the low impedance terminal i of T2 (i.e., the other end 5224 of the outer conductor of the straight coaxial cable 522) is connected to the arc segment outer conductor 516 of the "U" shaped cable cluster to achieve ground. The other connection method is the same as the first scheme. This embodiment scheme can be implemented (N-1/2)²1 impedance transformation ratio.

A third version of example 1 of the invention is shown in figure 12. The second series connection mode is adopted in this embodiment, and is different from the second scheme in fig. 11 in that the inner conductors of two straight coaxial cables 521 and 522 of the melon pull-in transformer T2 are defined as a conductor R3, and the outer conductor is defined as a conductor R4, so that at the high-impedance end of T2, one end 5221 of the inner conductor of the straight coaxial cable 522 is a high-impedance terminal k, and one end 5211 of the inner conductor of the straight coaxial cable 521 is a high-impedance terminal m; the outer conductor end 5222 of the straight coaxial cable 522 is connected to the outer conductor end 5212 of the straight coaxial cable 521. At the low impedance end of T2, the other end 5223 of the inner conductor of the straight coaxial cable 522 serves as the low impedance terminal i of T2, and the other end 5213 of the inner conductor of the straight coaxial cable 521 serves as the low impedance terminal j of T2. The other connection is the same as the second scheme. This embodiment scheme can be implemented (N-1/2)²1 impedance transformation ratio.

A fourth version of example 1 of the invention is shown in figure 13. The present embodiment adopts the first series connection manner, and is different from the first scheme of fig. 10 in that the inner conductors of the two straight coaxial cables 521 and 522 defining the melon pull-in transformer T2 are the conductors R3, and the outer conductor is the conductor R4. The high impedance terminal of T2 is connected in the same manner as in the third scheme (fig. 12). Low impedance of T2The other end 5223 of the inner conductor of the straight coaxial cable 522 is connected as a low impedance terminal i to the high impedance terminal h of the winding transformer T1 (i.e., the other end 5132 of the inner conductor of the second straight coaxial cable 513). The other end 5213 of the inner conductor of the straight coaxial cable 521 serves as a low impedance terminal j which is connected to the "U" shaped cable cluster arc 516 of T1 for grounding purposes. The scheme of the embodiment can be realized (N +1/2)²1 impedance transformation ratio.

Example two:

the transmission line transformer with non-integer square transformation ratio of the present embodiment has a structure as shown in fig. 14, and includes an impedance transformation ratio of 1: N²Winding transformer T1 and a melon pull-in transformer T2 with a 4:1 impedance transformation ratio. The first solution is basically similar to the first solution of the first embodiment, but the difference between the two solutions is that a separate wire 623 is added to the melon pull-in transformer T2. At the high impedance port of T2, one end 6231 of the individual wire 623 is connected to the high impedance terminal k of T2; at the low impedance port of T2, the other end 6232 of individual conductor 623 is connected to the "U" shaped cable cluster arc 516 and thus to ground. Other structures and connection relations in this embodiment are the same as those in the first embodiment, and the impedance transformation ratio is also the same. The addition of the separate wire 623 improves the balance of the external low-resistance terminal a and the external low-resistance terminal b.

Similarly, the additional independent wire 623 of the present embodiment can also be added to the second, third, and fourth solutions of the first embodiment. In the second scheme, one end 6231 of the independent wire 623 is connected with the high impedance terminal m (fig. 11) of T2; in the third scenario, one end 6231 of the individual wire 623 is connected to the high impedance terminal m (fig. 12) of T2; in the fourth scenario, one end 6231 of the individual wire 623 is connected to the high impedance terminal k (fig. 13) of T2. In the above arrangement, the other ends 6232 of the individual conductors are each connected to the "U" shaped cable cluster arcuate segment 516 and thus grounded.

Example three:

the transmission line transformer with non-integer square transformation ratio of the embodiment has the same principle, structure and connection relation with the second scheme of the first embodiment, except that: in this embodiment, a magnetic core 71 shown in fig. 15 is further added, the magnetic core is a rectangular parallelepiped structure, two through rectangular holes 711 and 712 are formed in the middle of the magnetic core, circular holes 713 and 714 are formed in the tops of the rectangular holes 711 and 712, and all the circular holes penetrate through the entire magnetic core 71. The third embodiment is composed of a winding type transformer T1 and a zener type transformer T2, as shown in fig. 16. The U-shaped cable cluster, the first straight coaxial cable 512 and the second straight coaxial cable 513 of the winding transformer T1 are correspondingly installed in the two rectangular holes 711 and 712, and the straight coaxial cables 521 and 522 of the melon inner pull type transformer T2 are respectively installed in the two round holes 713 and 714 at the top, as shown in fig. 17. The ends of all the cables are exposed outside the core 71 and are connected in the areas 74 and 75, respectively, shown in fig. 18, according to the second embodiment.

In the present embodiment, two circular holes are provided, and in other embodiments, three circular holes may be provided side by side, wherein the independent wire 623 in the second embodiment is disposed in the circular hole in the middle.

In the third embodiment, 3mm diameter 25 Ω coaxial cables are used to manufacture the cable sections in the winding type transformer and the melon inner pull type transformer respectively. The number of the U-shaped cables in the winding type transformer is 2. The ferrite relative permeability of the core 71 is 100, and the length direction thereof is 40 to 60 mm. In the arc-shaped section of the U-shaped cable cluster, for convenient connection, the end of the first straight coaxial cable 512 is bent downwards, and the inner conductor of the first straight coaxial cable can be connected with an external circuit system to be used as a high-impedance terminal; the end of the second straight coaxial cable 513 is bent along the arc line of the U-shaped bottom, and then is connected to the straight coaxial cables 521 and 522 of the melon pull-in transformer, respectively. This example can theoretically achieve 2.5²1 impedance transformation ratio.

The third embodiment is subjected to a full-network S parameter test, and then the differential impedance of the two low impedance ports to the ground is calculated, as shown in fig. 19 and 20. According to the theoretical transformation ratio relation, the differential impedance is 50/6.25-8 Ω when the high-impedance termination is 50 Ω load, and after the high-impedance termination is split into 2 ground resistors, each of the resistors is 4 Ω. The actual measurement result shows that in a short wave frequency band of 2 MHz-30 MHz, the real part of the differential mode impedance is 4 +/-0.12 omega, and the deviation between two ports is less than 0.1 omega; the imaginary part is weak inductive, and better tuning can be realized by connecting capacitive reactance in parallel with the port. Fully describing the characteristics of the differential port, attention is also paid to the common-mode impedance to the ground, and the measured result is shown in fig. 21, wherein the amplitude of the lowest common-mode impedance exceeds 40 Ω, which is 10 times of the differential-mode impedance. The measured results show that the impedance transformation ratio of the transmission line transformer of the embodiment meets the non-integer square relation of 6.25:1, the differential mode impedance is good in balance, the reactance is small, the common mode impedance is 10 times of the differential mode impedance at the minimum, and the common mode rejection is good.

It should be noted that, in the above embodiments, all the cable conductors may be connected by direct cable butt joint, wire connection, Printed Circuit Board (PCB), and the like, and the connection means does not belong to the technical features of the present invention.

What has been described above are merely some embodiments of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept thereof, and these changes and modifications can be made without departing from the spirit and scope of the invention.

Claims (11)

1. A transmission line transformer having a non-integer square transformation ratio, characterized by: it comprises an impedance transformation ratio of 1: N²Winding type transformer T1 and melon pull-in type transformer T2 with impedance transformation ratio of 4:1, N is an integer more than or equal to 2; the winding transformer T1 and the melon pull-in transformer T2 are both provided with a low impedance port and a high impedance port; the low-impedance port of the winding transformer T1 is connected in parallel with the high-impedance port of the melon pull-in transformer T2 to form a total outward low-impedance port of the transmission line transformer; winding formula transformer T1's high impedance port with draw formula transformer T2's low impedance port is established ties in the melon, forms after establishing ties the general external high impedance port of transmission line transformer.

2. The transmission line transformer with non-integer square transformation ratio of claim 1, wherein:

the low-impedance port of the winding transformer T1 is composed of a low-impedance terminal e and a low-impedance terminal f;

the high-impedance port of the winding type transformer T1 is composed of a high-impedance terminal g and a high-impedance terminal h;

the low impedance terminal e of the winding transformer T1 is in phase with the high impedance terminal g;

the low-impedance port of the melon pull-in transformer T2 is composed of a low-impedance terminal i and a low-impedance terminal j;

the low-impedance port of the melon pull-in transformer T2 is composed of a high-impedance terminal k and a high-impedance terminal m;

the low impedance terminal i of the melon pull-in transformer T2 is in phase with the high impedance terminal k.

3. The transmission line transformer with non-integer square transformation ratio of claim 2, wherein: the high-impedance port of the winding transformer T1 and the low-impedance port of the melon pull-in transformer T2 are connected in series in a first series mode

The impedance transformation ratio of (1); the first series mode is as follows: the low impedance terminal i of T2 is connected with the high impedance terminal h of T1, and the low impedance terminal j of T2 is grounded; or

The high-impedance port of the winding transformer T1 and the low-impedance port of the melon inner pull type transformer T2 are connected in series in a second series connection mode to realize

The impedance transformation ratio of (2); the second series connection mode is as follows: the low impedance terminal j of T2 is connected to the high impedance terminal h of T1, and the low impedance terminal i of T2 is grounded.

4. The transmission line transformer with non-integer square transformation ratio of claim 2 or 3, wherein: the winding transformer T1 comprises N transmission lines TL₁～TL_N(ii) a Each segment of the transmission line comprises a conductor R1 and a conductor R2 which are equal in length; the conductors R1 in the N-section transmission lines are sequentially connected in series end to end, and the transmission line TL₁The starting terminal of (A) constitutes the high impedance terminal g, TL of T1_NToThe terminal constitutes a high impedance terminal h of T1; one end of a conductor R2 in the N-segment transmission line is connected in parallel to form a low-impedance terminal e of the T1, the other end of the conductor R2 is connected in parallel to form a low-impedance terminal f of the T1, and the central points of all conductors R2 are grounded.

5. The transmission line transformer with non-integer square transformation ratio of claim 3, wherein: melon pull-in transformer T2 includes two sections isometric transmission lines TL_N+1And TL_N+2(ii) a Each segment of the transmission line comprises conductors R3 and R4 with equal length; transmission line TL_N+1One end of the conductor R3 and the transmission line TL_N+2One end of the conductor R4 in the T2 is connected in parallel to form a low-impedance terminal i of a transmission line TL_N+1One end of the conductor R4 and the transmission line TL_N+2One end of the conductor R3 in the T2 is connected in parallel to form a low impedance terminal j; transmission line TL_N+1The other end of the conductor R3 forms the high impedance terminal k of T2, the transmission line TL_N+1The other end of the middle conductor R4 and the transmission line TL_N+2The other end of the middle conductor R3 is connected to the transmission line TL_N+2The other end of the conductor R4 in (1) constitutes a high impedance terminal m of T2.

6. The transmission line transformer with non-integer square transformation ratio of claim 5, wherein: the winding type transformer T1 comprises N-1U-shaped coaxial cables and two straight coaxial cables; the N-1U-shaped coaxial cables are stacked in parallel and the outer conductors of the U-shaped coaxial cables are in close contact to form a U-shaped cable cluster, wherein a first straight coaxial cable is tightly attached to a straight edge on one side of the U-shaped cable cluster from the lower side in parallel, a second straight coaxial cable is tightly attached to a straight edge on the opposite side of the U-shaped cable cluster from the upper side in parallel, and the outer conductors of the two straight coaxial cables are in close contact with the outer conductor of the U-shaped cable cluster;

at the opening end of the U-shaped cable cluster, an inner conductor of a first straight coaxial cable is connected with an inner conductor of the opposite side straight edge of the lowest U-shaped coaxial cable in the U-shaped cable cluster, an inner conductor of the same side straight edge of the U-shaped coaxial cable is connected with an inner conductor of the opposite side straight edge of the U-shaped coaxial cable in the previous layer, and the U-shaped coaxial cable is pushed up layer by layer until the top layer is reached; the straight-side inner conductor of the U-shaped coaxial cable on the same side of the topmost layer is connected with the inner conductor of the second straight coaxial cable on the opposite side;

in the U-shaped cable cluster, the straight-side outer conductors of the U-shaped coaxial cables on the same side as the second straight coaxial cable are integrally connected to form a low-impedance terminal e of T1, and the straight-side outer conductors of the U-shaped coaxial cables on the same side as the first straight coaxial cable are integrally connected to form a low-impedance terminal f of T1; one end of the inner conductor of the first straight coaxial cable, which is close to the arc section of the U-shaped coaxial cable, forms a high-impedance terminal g of T1, and one end of the inner conductor of the second straight coaxial cable, which is close to the arc section of the U-shaped coaxial cable, forms a high-impedance terminal h of T1; the outer conductors of the "U" shaped cable cluster are integrally connected together at the arcuate segments and grounded.

7. The transmission line transformer with non-integer square transformation ratio of claim 6, wherein: melon inner pull type transformer T2 is located winding formula transformer T1 top, except the connection between the terminal, two sections transmission line TL of T2_N+1And TL_N+2Does not contact T1; the high impedance port of T2 is located on the open side of the "U" shaped cable cluster of T1 and the low impedance port of T2 is located on the arcuate end side of the "U" shaped cable cluster of T1.

8. The transmission line transformer with non-integer square transformation ratio of claim 6, wherein: transmission line TL of melon inner pull type transformer T2_N+1And TL_N+2Is a coaxial cable; in the two sections of the transmission line,

the inner conductor of the coaxial cable is the conductor R3, and the outer conductor is the conductor R4; or alternatively

The outer conductor of the coaxial cable is the conductor R3, and the inner conductor is the conductor R4.

9. The transmission line transformer with non-integer square transformation ratio of claim 5, wherein: the melon inner pull type transformer T2 further comprises an independent lead, and the length of the independent lead is the same as that of a transmission line in the melon inner pull type transformer T2;

in the first series mode, one end of the independent wire is connected with a high-impedance terminal k of T2, and the other end of the independent wire is connected with a low-impedance terminal j of T2 and grounded;

in the second series connection, one end of the individual wire is connected to the high impedance terminal m of T2, and the other end is connected to the low impedance terminal i of T2 and grounded.

10. The transmission line transformer with non-integer square transformation ratio of claim 6, wherein: the magnetic core comprises at least two through rectangular holes and at least two through circular holes; the circular hole is correspondingly arranged above each rectangular hole; the U-shaped cable cluster of the winding type transformer T1 and the first and second straight coaxial cables are arranged in the rectangular hole, and the open end and the arc end of the U-shaped cable cluster are connected with corresponding conductors outside the magnetic core; transmission line TL of melon inner pull type transformer T2_N+1And TL_N+2Located in two of the circular holes, respectively, transmission lines TL_N+1And TL_N+2The two ends of the magnetic core extend out of the magnetic core and are connected with corresponding conductors.

11. The transmission line transformer with non-integer square transformation ratio of claim 10, wherein: the melon inner pull type transformer T2 further comprises an independent lead, and the length of the independent lead is the same as that of a transmission line in the melon inner pull type transformer T2;

in the first series mode, one end of the independent wire is connected with a high-impedance terminal k of T2, and the other end of the independent wire is connected with a low-impedance terminal j of T2 and grounded;

in the second series connection mode, one end of the independent wire is connected with the high-impedance terminal m of T2, and the other end is connected with the low-impedance terminal i of T2 and grounded;

the circular port has set gradually three side by side, independent wire setting is in middle circular port.

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