WO2018171224A1 - Wideband balun structure - Google Patents

Abstract

The present invention provides a wideband balun structure. The wideband balun structure comprises a substrate, a first metal part attached to the upper surface of the substrate, and a second metal part attached to the lower surface of the substrate. The first metal part is of a tower-shaped structure; the second metal part comprises a cuboid and a concave protrusion located on a protrusion side edge of the cuboid; the first metal part and the second metal part are connected. By implementing the present invention, a phase difference between adjacent output ports can be kept stable around 180°, achieving a good phase shift effect between two output ports.

Description

Broadband balun structure Technical field

The present invention relates to the field of communications technologies, and in particular, to a broadband balun structure.

Background technique

Broadband is usually used for reasons such as power (and other common mode) noise immunity, even harmonic distortion cancellation, DC offset term elimination, increased dynamic range due to swing on the two outputs, etc. DC-coupled amplifiers are designed with differential inputs and outputs. For interconnects between a small chip, a package, or even an amplifier on a single board, the cost of differential interconnects is small compared to the advantages of differential design. However, for interconnects between modules, such as the interconnection between active probes and oscilloscopes, the cost of differential interconnects is often very high. Not only do two coaxial cables be needed instead of one (increasing cost and size and reducing flexibility), but the two coaxial cables also need to be tightly matched to prevent mode switching from differential mode to common mode and from common mode to differential mode. Mode conversion.

Various passive interconnect structures known to convert between single-ended and differential signals are often referred to as "baluns" in time domain applications and/or often referred to as "180°" in frequency domain applications. Hybrid. The wideband dc-coupled passive balun is limited by at least a 3dB loss because no energy at dc can be coupled to a capacitive or inductive coupling to the "reverse" output, and therefore half of the single-ended input power behaves as a differential The "wasted" common mode energy is output.

Typically, baluns are designed for RF applications with little or no consideration for the transient response of the balun. The transient response in such a device can have considerable pre-shoot or pre-shoot and over shoot. However, in some applications, such as signal acquisition systems with differential signal acquisition probes coupled to oscilloscopes, the phase difference between adjacent ports in existing balun designs is unstable and cannot be stabilized around 180°. Moreover, the phase shifting effect is poor, the stability of the communication signal is reduced, and the signal transmission between the communication devices is disadvantageous.

technical problem

The main object of the present invention is to provide a broadband balun structure, which aims to solve the technical problem that the phase difference between adjacent ports in the prior art is unstable and the phase shifting effect is poor.

Problem solution

Technical solution

To achieve the above object, the present invention provides a broadband balun structure including a substrate, a first metal portion attached to an upper surface of the substrate, and a lower surface of the substrate Second metal portion;

The first metal portion is a tower structure, and comprises a tower body composed of a plurality of metal sheets superposed and a tower base composed of two base metal sheets on the left and right sides of the tower body, except for the top metal piece at the top of the tower body. The other metal sheets constituting the tower body are provided with slits, and each of the slits is further provided with a blocking resistor, and one of the base metal sheets in the tower base is provided with a connection region;

The second metal portion includes a rectangular parallelepiped and a concave protruding portion located at a side of the rectangular parallelepiped protruding portion, and the connecting portion is disposed in the concave protruding portion;

A through hole is disposed in the substrate, and a metal pillar is disposed in the through hole, and the through hole corresponds to a connection region of the base metal piece and a connection region of the concave protrusion, and the connection between the metal pillar and the base metal piece a region and a connection region of the concave protrusion are connected; and

The broadband balun structure further includes an input port, a first output port, and a second output port, wherein the input port is connected to a frame of the top metal piece and the second metal part of the tower body of the first metal part The first output port is connected to a terminal of a base metal piece of the tower base of the first metal portion and a frame of the second metal portion, and the second output port and the base of the first metal portion The end of one of the base metal pieces is connected to the end of the concave protrusion of the second metal portion.

Preferably, the first metal portion and the second metal portion are both copper surfaces and have the same thickness.

Preferably, the first metal portion includes a first isolation resistor, a second isolation resistor, a third isolation resistor, a fourth isolation resistor, a first metal piece, a second metal piece, a third metal piece, and a fourth a metal piece, a fifth metal piece, a sixth metal piece, a first base and a second base, wherein the first metal piece, the second metal piece, the third metal piece, and the fourth metal part The sheet, the fifth metal sheet and the sixth metal sheet are superposed to form a tower body, and the first base and the second base form a tower base.

Preferably, the first metal piece is a top metal piece and has a rectangular solid structure, and the second metal piece, the third metal piece, the fourth metal piece, the fifth metal piece and the sixth section The metal sheets are all rectangular and have a structure inside the slit, and the first metal piece, the second metal piece, the third metal piece, The dimensions of the fourth metal piece, the fifth metal piece and the sixth metal piece are enlarged by section, the first isolation resistor is disposed in the slit of the second metal piece, and the second isolation resistance is disposed on the third metal part In the gap of the chip, the third isolation resistor is disposed in the slit of the fourth metal piece, the fourth isolation resistor is disposed in the slit of the fifth metal piece, and the fifth isolation resistance is disposed in the gap of the sixth metal piece.

Preferably, the bottom of the first metal piece is connected to the middle of the top of the second metal piece, the bottom of the second metal piece is connected to the middle of the top of the third piece of metal, and the third piece of metal The bottom is connected to the middle of the top of the fourth metal piece, the bottom of the fourth metal piece is connected to the middle of the top of the fifth metal piece, and the bottom of the fifth metal piece is connected to the sixth piece of metal piece. The middle position of the top.

Preferably, a first base is disposed on a left side of the sixth metal piece, and a second base is disposed on a right side of the sixth metal piece.

Preferably, the second base is a metal piece having an arc shape in the middle, wherein the second base comprises a first folded metal piece and a second folded metal piece, the first folded metal piece and the second folded shape Forming a fold gap at the junction of the metal sheets;

The first folded metal piece is provided with a first connection area, and the second folded metal piece is provided with a second connection area;

The first connection area and the second connection area respectively correspond to two through holes of the substrate.

Preferably, the fold gap formed by the joint of the first folded metal piece and the second folded metal piece is a Z-shaped slit.

Preferably, the concave protrusion comprises a first concave metal piece and a second concave metal piece, and the first concave metal piece and the second concave metal piece are joined to form a folding gap, the first A concave metal piece includes a third connection region, and the second concave metal piece is provided with a fourth connection region, and the third connection region and the fourth connection region respectively correspond to the two through holes of the substrate.

Preferably, the fold-shaped slit formed by the joint of the first concave metal piece and the second concave metal piece is a Z-shaped slit.

Advantageous effects of the invention

Beneficial effect

The technical solution of the present invention adopts the above technical solution, and the technical effect of the invention is that the broadband balun structure of the present invention is in phase The phase difference between the adjacent output ports can be stabilized at around 180°, achieving a good phase shifting effect between the two output ports.

Brief description of the drawing

DRAWINGS

1 is a schematic structural view of a broadband balun structure of the present invention;

2 is a schematic structural view of a first metal portion of a preferred embodiment of the broadband balun structure of the present invention;

Figure 3 is a dimensional illustration of the components of the first metal portion of the preferred embodiment of the broadband balun structure of the present invention;

4 is a schematic structural view of a second base in a first metal portion of a preferred embodiment of the broadband balun structure of the present invention;

Figure 5 is a schematic view showing the structure of a second metal portion of a preferred embodiment of the broadband balun structure of the present invention;

6 is a schematic structural view of a concave protrusion in a second metal portion of a preferred embodiment of the broadband balun structure of the present invention;

7 is an S-parameter diagram of a preferred embodiment of the present invention after electromagnetic simulation of a broadband balun structure;

Figure 8 is a schematic illustration of a preferred embodiment of the phase difference between two output ports after electromagnetic simulation of a broadband balun structure in accordance with the present invention.

The object, features, and advantages of the invention will be further described in conjunction with the embodiments.

BEST MODE FOR CARRYING OUT THE INVENTION

BEST MODE FOR CARRYING OUT THE INVENTION

The specific embodiments, structures, features and functions of the present invention are described in detail below with reference to the accompanying drawings and preferred embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to Fig. 1, Fig. 1 is a schematic structural view of a broadband balun structure of the present invention.

The broadband balun structure 1 of the present invention includes a first metal portion 10, a substrate 20, and a second metal portion 30. In this embodiment, the broadband balun structure 1 is a rectangular parallelepiped structure having a length M, a width N, and a thickness X (not shown), wherein M is preferably 72.7 mm, and N is preferably 59.2 mm. , X is preferably 1 mm.

The first metal portion 10 is attached to the upper surface of the substrate 20, and the second metal portion 30 is attached to the lower surface of the substrate 20. Two through holes 5 (that is, holes whose front faces vertically penetrate the substrate 20) are further disposed in the substrate 20, and the through holes 5 are provided with connecting the first metal portion 10 and the second metal portion 30. Metal column (not shown). The first metal portion 10 and the second metal portion 30 are both copper surfaces and have the same thickness. Preferably, the first metal portion 10 and the second metal portion 30 have a thickness of 0.5 ounces.

In this embodiment, the substrate 20 is a printed circuit board. The substrate 20 preferably has a dielectric constant of 3.45.

The first metal portion 10 is a tower structure, and comprises a tower composed of a plurality of sections (for example, four, five or six sections) and a tower composed of two base metal sheets on the left and right sides of the tower body. base. Wherein, the top metal piece at the top of the tower body is a solid long strip structure, and other metal sheets constituting the tower body except the top metal piece at the top of the tower body are provided with slits, and each of the metal sheets is provided A barrier resistor is also provided between the slits. A connection area is provided in one of the base metal sheets in the base of the base.

The second metal portion 30 includes a rectangular parallelepiped and a concave protruding portion located at a side of the rectangular parallelepiped protruding portion, and the concave protruding portion is provided with a connecting region.

A through hole 5 (ie, a hole whose front surface vertically penetrates the substrate 20) is further disposed in the substrate 20, and a metal pillar is disposed in the through hole, and the through hole 5 corresponds to a connection region and a recess in the base metal piece. A connecting region in the protruding portion, the metal post is connected to a connecting region in the base metal piece and a connecting region in the concave protruding portion.

The broadband balun structure 1 further includes three ports, which are an input port 2, a first output port 3, and a second output port 4. The input port 2 is used for signal input, and the first output port 3 and the second output port 4 are used for signal output.

The input port 2 is connected to the top metal piece of the tower body of the first metal part 10 and the frame of the second metal part 30, and the first output port 3 and a base metal of the tower base of the first metal part 10 The end of the sheet is connected to the frame of the second metal portion 30, and the second output port 4 is connected to the end of one base metal piece of the tower base of the first metal portion 10 and the end of the concave protrusion 300 of the second metal portion 30. .

The structure of the broadband balun structure 1 will be described in detail below with reference to Figs. 2-6, wherein the first metal portion 10 includes six metal sheets.

Specifically, as shown in FIGS. 2 to 3, the first metal portion 10 includes a first isolation resistor R1 and a second isolation. a resistor R2, a third isolation resistor R3, a fourth isolation resistor R4, a first metal piece 100, a second metal piece 110, a third metal piece 120, a fourth metal piece 130, a fifth metal piece 140, The sixth section of the metal piece 150, the first base 160 and the second base 170.

The first metal portion 10 is a tower structure including a tower body and a tower base. The first metal piece 100, the second metal piece 110, the third metal piece 120, the fourth metal piece 130, the fifth metal piece 140, and the sixth metal piece 150 are stacked to form a tower body, and the first A base 160 and a second base 170 form a tower base.

The first metal piece 100 is a rectangular solid structure. The second metal piece 110, the third metal piece 120, the fourth metal piece 130, the fifth metal piece 140, and the sixth metal piece 150 are all rectangular and have a slit (rectangular slit) therein. The dimensions of the first metal piece 100, the second metal piece 110, the third metal piece 120, the fourth metal piece 130, the fifth metal piece 140, and the sixth metal piece 150 are enlarged by section.

Further, the bottom of the first metal piece 100 is connected to the middle of the top of the second metal piece 110, and the bottom of the second metal piece 110 is connected to the middle of the top of the third metal piece 120. The bottom of the three-section metal piece 120 is connected to the middle of the top of the fourth-section metal piece 130, the bottom of the fourth-section metal piece 130 is connected to the middle of the top of the fifth-section metal piece 140, and the fifth-section metal piece 140 The bottom is connected to the middle of the top of the sixth metal sheet 150.

The second metal piece 110, the third metal piece 120, the fourth metal piece 130, the fifth metal piece 140, and the sixth metal piece 150 are all rectangular and have a metal patch in the middle. The first isolation resistor R1 is disposed in the gap of the second metal piece 110, the second isolation resistor R2 is disposed in the gap of the third metal piece 120, and the third isolation resistor R3 is disposed in the gap of the fourth metal piece 130. The fourth isolation resistor R4 is disposed in the slit of the fifth metal piece 140, and the fifth isolation resistor R5 is disposed in the gap of the sixth metal piece 150.

A first base 160 is disposed on a left side of the sixth metal piece 150, and a second base 170 is disposed on a right side of the sixth metal piece 150. The first base 160 is a metal piece with a rectangular solid structure. The second base 170 is an elongated structure.

As shown in FIG. 3, the width of the first isolation resistor R1 is S1, the width of the second isolation resistor R2 is S2, the width of the third isolation resistor R3 is S3, and the width of the fourth isolation resistor R4 is S4.

The first metal piece 100 has a length L0 and a width W0;

The length of the second metal piece 110 is L1, the width of the second metal piece 110 is 2*W1+S1, and the width of the gap in the second metal piece 110 is S1. In other words, the second metal piece 110 is equivalent. In two parallel metal sheets, each metal has a length L1 and a width W1, and a gap width between the two metal sheets arranged in parallel is S1;

The length of the third metal piece 120 is L2, the width of the third metal piece 120 is 2*W2+S2, and the width of the slit in the third metal piece 120 is S2. In other words, the third metal piece 120 is equivalent. In two parallel metal sheets, each metal has a length L2 and a width W2, and a gap width between the two metal sheets arranged in parallel is S2;

The length of the fourth metal piece 130 is L3, the width of the fourth metal piece 130 is 2*W3+S3, and the width of the slit in the fourth metal piece 130 is S3. In other words, the fourth metal piece 130 is equivalent. In two parallel metal sheets, each metal has a length L3 and a width W3, and a gap width between the two metal sheets arranged in parallel is S3;

The length of the fifth metal piece 140 is L4, the width of the fifth metal piece 140 is 2*W4+S4, and the width of the slit in the fifth metal piece 140 is S4. In other words, the fifth metal piece 140 is equivalent. In the two metal sheets juxtaposed, each metal has a length of L4 and a width of W4, and a gap width between the two metal sheets arranged in parallel is S4;

The length of the sixth metal piece 150 is L5, the width of the sixth metal piece 150 is 2*W5+S5, and the width of the gap in the sixth metal piece 150 is S5. In other words, the sixth metal piece 150 is equivalent. In the two metal sheets juxtaposed, each metal has a length L5 and a width W5, and a gap width between the two metal sheets arranged in parallel is S5;

The first base 160 has a length L7 and a width W0; the second base 170 has a length L7 and a width at both ends of W0.

As shown in FIG. 4, the second base 170 is a metal piece having an arc shape in the middle. The second base 170 includes a first folded metal piece 1701 and a second folded metal piece 1703, wherein the first folded metal piece 1701 and the second folded metal piece 1703 form a fold gap at the joint ( Not marked in the figure).

Further, the first folded metal piece 1701 is provided with a first connection region 1702, and the second folded metal piece 1703 is provided with a second connection region 1704.

The first connection region 1702 and the second connection region 1704 respectively correspond to the two through holes 5 of the substrate 20 .

As shown in FIG. 5 , the second metal portion 30 includes a concave protrusion 300 and a rectangular parallelepiped 310 , and the concave protrusion 300 is disposed at a side of the rectangle 310 . As shown in FIG. 6, the concave protrusion 300 includes a first concave metal piece 301 and a second concave metal piece 303, wherein the first concave metal piece 301 and the second concave metal piece 303 are connected. A fold-shaped slit is formed (not labeled in the figure). Further, the first concave metal piece 301 is provided with a third connection region 302, and the second concave metal piece 303 is provided with a fourth connection. Area 304. The third connection region 302 and the fourth connection region 304 respectively correspond to the two through holes 5 of the substrate 20 . The length of the rectangular parallelepiped 310 is M (ie, the same length as the substrate), and the width is N-L6, wherein the L6 is the length of the concave protrusion 300. The width of both ends of the concave protrusion 300 is W6.

Further, a metal post (or a wire) in the substrate 20 is disposed in the through hole 5 and connected to the first connection region 1702 and the second connection region 1704. The metal pillars (or wires) in the substrate 20 are also connected to the third connection region 302 and the fourth connection region 304.

The broadband balun structure 1 further includes three ports, which are an input port 2, a first output port 3, and a second output port 4. The input port 2 is used for signal input, and the first output port 3 and the second output port 4 are used for signal output.

The input port 2 is connected to the top of the first metal piece 100 and the second metal part 30. The first output port 3 is connected to the end of the first base 160 and the second metal part 30, and the second output port 4 is connected. The end of the second base 170 and the concave protrusion 300 are connected.

With the wide-band balun of the above structure, the antenna can operate in the range of 1 GHz to 8 GHz, and a good 180° phase shifting effect can be achieved in this range.

In this embodiment, the broadband balun structure is simulated by the following parameters, and the specific parameters are as follows:

[Table 1]

L0	W0	L1	W1	S1	L2
10mm	2.18mm	10.3mm	1mm	0.45mm	10.3mm
W2	S2	L3	W3	S3	L4
1.2mm	0.34mm	10.1mm	1.57mm	0.34mm	10mm
W4	S4	L5	W5	S5	L6
1.95mm	0.31mm	12mm	2.22mm	0.43mm	15.8mm
W6	L7	R1	R2	R3	R4
8mm	28.3mm	52Ω	108Ω	180Ω	300Ω
R5
800Ω

As shown in Fig. 7, Fig. 7 is the S-parameter result simulated by the electromagnetic simulation software. It can be seen from Fig. 7 that the reflection coefficient (|S11|) of the balun is below -10 dB in the range of 1 GHz to 8 GHz, indicating that the balun It can work in 1GHz to 8GHz to achieve broadband characteristics. |S23| Below -19dB in the operating band, this balun has good isolation characteristics. |S21| is nearly equal to |S31|, all around -3dB, indicating that energy can be divided into nearly two equal parts from port 1 to port 2 and port 3.

The phase difference between the first output port 3 and the second output port 4 is shown in Fig. 8, and it can be seen that the phase difference between adjacent ports is stable at around 180°. This shows that there is an excellent phase shift between the two output ports of the balun. In combination with Figure 7, since the energy between the two output ports is equal amplitude and the phase difference is 180°, this balun can be widely used in the feeding of wideband differential antennas, and can also be applied in the field of radio frequency, which requires uniform phase shifting. The effect of the RF device.

The above are only the preferred embodiments of the present invention, and are not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformations made by the description of the present invention and the contents of the drawings, or indirectly or indirectly in other related technical fields. The same is included in the scope of patent protection of the present invention.

Industrial applicability

The technical solution of the present invention adopts the above technical solution, and the technical effect of the invention is that the broadband balun structure of the present invention is in phase The phase difference between the adjacent output ports can be stabilized at around 180°, achieving a good phase shifting effect between the two output ports.

Claims (10)

1. A broadband balun structure, characterized in that the broadband balun structure comprises a substrate, a first metal portion attached to an upper surface of the substrate, and a second metal portion attached to a lower surface of the substrate; The first metal portion is a tower structure, and comprises a tower body composed of a plurality of metal sheets superposed and a tower base composed of two base metal sheets on the left and right sides of the tower body, except for the top metal piece at the top of the tower body. The other metal sheets constituting the tower body are provided with slits, and each of the slits is further provided with a blocking resistor, and one of the base metal sheets in the tower base is provided with a connection region; the second metal portion includes a rectangular parallelepiped and a concave protrusion located at a side of the protrusion of the rectangular parallelepiped, wherein the concave protrusion is provided with a connection region; a through hole is disposed in the substrate, and a metal pillar is disposed in the through hole, and the through hole corresponds to the base a connection region of the metal piece and a connection region of the concave protrusion, the metal post is connected to the connection region of the base metal piece and the connection region of the concave protrusion; and the broadband balun structure further includes an input port, the first An output port and a second output port, wherein the input port is connected to a top metal piece of the tower body of the first metal portion and a frame of the second metal portion, the first output port and the first metal The end of one base metal piece of the tower base and the frame of the second metal part are connected, the second output port and the end of the base metal piece of the base of the first metal part and the second metal part The ends of the concave projections are connected.
2. The broadband balun structure according to claim 1, wherein the first metal portion and the second metal portion are both copper faces and have the same thickness.
3. The broadband balun structure according to claim 1, wherein the first metal portion comprises a first isolation resistor, a second isolation resistor, a third isolation resistor, a fourth isolation resistor, a first metal piece, and a first Two metal sheets, a third metal sheet, a fourth metal sheet, a fifth metal sheet, a sixth metal sheet, a first base and a second base, wherein the first metal piece and the second section The metal piece, the third metal piece, the fourth metal piece, the fifth metal piece and the sixth metal piece are superposed to form a tower body, and the first base and the second base form a tower base.
4. The broadband balun structure of claim 3 wherein said first section metal The sheet is a top metal sheet and has a rectangular solid structure, and the second metal sheet, the third metal sheet, the fourth metal sheet, the fifth metal sheet and the sixth metal sheet are rectangular and have a slit inside. The size of the first metal piece, the second metal piece, the third metal piece, the fourth metal piece, the fifth metal piece, and the sixth metal piece are enlarged by a section, the first The isolation resistor is disposed in the slit of the second metal piece, the second isolation resistor is disposed in the slit of the third metal piece, the third isolation resistance is disposed in the gap of the fourth metal piece, and the fourth isolation resistance is disposed in the first In the slit of the five-section metal piece, the fifth isolation resistor is disposed in the slit of the sixth metal piece.
5. The broadband balun structure according to claim 4, wherein a bottom portion of the first metal piece is connected to an intermediate position of a top portion of the second metal piece, and a bottom portion of the second metal piece is connected to the third portion. The middle position of the top of the metal piece, the bottom of the third metal piece is connected to the middle of the top of the fourth piece of metal piece, and the bottom of the fourth piece of metal piece is connected to the middle of the top of the fifth piece of metal piece, the fifth The bottom of the metal piece is connected to the middle of the top of the sixth metal piece.
6. The broadband balun structure according to claim 4, wherein a first base is disposed on a left side of the sixth metal piece, and a second base is disposed on a right side of the sixth metal piece.
7. The broadband balun structure according to claim 6, wherein the second base is a metal piece having an arc shape in the middle, wherein the second base comprises a first folded metal piece and a second folded metal piece. Forming a fold-shaped slit at the junction of the first folded metal piece and the second folded metal piece; the first folded metal piece is provided with a first connecting region, and the second folded metal piece is provided with a second a connection area; the first connection area and the second connection area respectively correspond to two through holes of the substrate.
8. The broadband balun structure according to claim 7, wherein the fold-shaped slit formed by the joint of the first folded metal piece and the second folded metal piece is a Z-shaped slit.
9. The broadband balun structure of claim 1 wherein said concave projection comprises a first concave metal sheet and a second concave metal sheet, said first concave metal sheet and said second concave shape Forming a fold-shaped slit at the junction of the metal sheets, the first concave metal sheet includes a third connection region, and the second concave metal sheet is provided with a fourth connection region, The third connection region and the fourth connection region respectively correspond to the two through holes of the substrate.
10. The broadband balun structure according to claim 9, wherein the fold-shaped slit formed by the joint of the first concave metal piece and the second concave metal piece is a Z-shaped slit.

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