CN215816342U

CN215816342U - Low-insertion-loss miniaturized millimeter wave dual-band power divider with high frequency ratio

Info

Publication number: CN215816342U
Application number: CN202122412069.3U
Authority: CN
Inventors: 陈锡聪; 林福民; 周冬跃; 李红涛; 王媛媛
Original assignee: Guangdong Fractional Dimension Wireless Technology Co ltd; Guangdong University of Technology
Current assignee: Guangdong Fractional Dimension Wireless Technology Co ltd; Guangdong University of Technology
Priority date: 2021-10-08
Filing date: 2021-10-08
Publication date: 2022-02-11
Anticipated expiration: 2031-10-08

Abstract

The utility model relates to the field of passive equipment, in particular to a low-insertion-loss miniaturized millimeter wave dual-band power divider with high frequency ratio and a design method thereof, wherein the millimeter wave dual-band power divider comprises a dielectric sheet and a plurality of one-to-two microstrip structures arranged on the dielectric sheet; the multiple one-to-two microstrip structures are connected to form a multi-stage power distribution unit, the input end of the one-to-two microstrip structure positioned in the first-stage power distribution unit is an input port of the millimeter wave dual-band power divider, and the output ends of the multiple one-to-two microstrip structures positioned in the last-stage power distribution unit are multiple output ports of the millimeter wave dual-band power divider; two one-to-two microstrip structures of two adjacent stages are connected through a second transmission microstrip line. The utility model can realize the dual-band work with high frequency ratio, and has lower insertion loss, higher isolation of each port and smaller size.

Description

Low-insertion-loss miniaturized millimeter wave dual-band power divider with high frequency ratio

Technical Field

The utility model relates to the field of passive equipment, in particular to a low-insertion-loss miniaturized millimeter wave dual-band power divider with high frequency ratio.

Background

At present, a power distributor is widely applied to systems such as microwave communication, satellite communication, testing instruments and meters, and the like, and mainly has the function of distributing microwave power of a working frequency band to lower-level cascade equipment with different paths, so that power distribution or synthesis is realized. The power divider is called a power divider for short, and is used for dividing an input signal to two or more output ports according to a certain proportion so as to realize the distribution of signal power. A plurality of single-frequency, wide-frequency and low-frequency ratio dual-frequency power dividers are available in the market, but a millimeter wave dual-frequency one-to-many power divider with a high frequency ratio is lacked.

The power divider capable of working in the millimeter wave frequency band generally adopts the technical means of waveguide or microstrip lines, adopts the waveguide mode, has a complex structure and a large volume, and is not beneficial to practical application. However, with the microstrip line technology, the insertion loss of the existing structure is very large, that is, when power is distributed, much energy is lost by various reasons when passing through the power divider, and the energy distributed to each port is less.

The power divider capable of working in the millimeter wave frequency band has to have a very delicate structure, so that the performance of the power divider in the millimeter wave frequency band is ensured, and the performance of the low frequency band in the dual frequency band is also ensured, which is a place difficult to overcome by the prior art.

Disclosure of Invention

In order to solve the technical problems in the prior art, the utility model provides a low-insertion-loss miniaturized high-frequency-ratio millimeter wave dual-band power divider and a design method thereof, which can realize high-frequency-ratio dual-band operation, and have the advantages of low insertion loss, high isolation of each port and small size.

The low-insertion-loss miniaturized millimeter wave dual-band power divider with high frequency ratio in one embodiment of the utility model comprises a dielectric sheet and a plurality of one-to-two microstrip structures arranged on the dielectric sheet; the multiple one-to-two microstrip structures are connected to form a multi-stage power distribution unit, the input end of the one-to-two microstrip structure positioned in the first-stage power distribution unit is an input port of the millimeter wave dual-band power divider, and the output ends of the multiple one-to-two microstrip structures positioned in the last-stage power distribution unit are multiple output ports of the millimeter wave dual-band power divider; two one-to-two microstrip structures of two adjacent stages are connected through a second transmission microstrip line.

In a preferred embodiment, the one-to-two microstrip structure includes a first transmission microstrip line, an impedance transformation microstrip line and an isolation resistor, wherein the first transmission microstrip line is located at an input end of the one-to-two microstrip structure, the isolation resistor is bridged at an end of the impedance transformation microstrip line, and an output end of the one-to-two microstrip structure is led out from the end of the impedance transformation microstrip line.

In a preferred embodiment, the final power distribution unit is also connected to the output port of the millimeter wave dual-band power divider through a second microstrip transmission line.

Compared with the prior art, the utility model has the following advantages and beneficial effects:

1. the utility model realizes the millimeter wave double-frequency one-to-eight power divider with high frequency ratio only by adopting double impedance conversion microstrip lines.

2. In each one-to-two microstrip structure, the two-section impedance conversion microstrip line has a dual-frequency-band impedance matching function and can generate resonance points in two frequency bands, and the two patch resistors arranged on the two-section impedance conversion microstrip line have an isolation function, so that two output ports have a certain isolation degree, and mutual coupling is reduced.

3. The power divider realizes the overall miniaturization through the optimization of the structure and length design, shortens the length of the microstrip line, and has lower double-frequency insertion loss except for a chip resistor for isolation and no other loss components.

Drawings

Fig. 1 is a schematic diagram of an overall structure of an one-to-eight power divider according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a one-to-two microstrip structure according to an embodiment of the present invention;

fig. 3 is a distribution diagram of microstrip lines and chip resistors of an one-to-eight power divider according to an embodiment of the present invention;

FIG. 4 is an equivalent circuit diagram of an one-to-eight power divider according to an embodiment of the present invention;

FIG. 5 is an equivalent circuit diagram of a dual-frequency Wilkinson power divider according to an embodiment of the present invention;

FIG. 6 is a circuit diagram of an even mode analysis in an embodiment of the present invention;

FIG. 7 is a circuit diagram of an odd mode analysis in an embodiment of the utility model;

FIG. 8 is a diagram of a test of the return loss S11 of the dual-band one-to-eight power divider at 4.9GHz in an embodiment of the present invention;

fig. 9 is a test chart of the return loss S11 of the dual-band one-to-eight power divider 26GHz in the embodiment of the present invention;

FIG. 10 is a diagram of the test of the return loss S22-S99 of the dual-band one-eight power divider at 4.9GHz in accordance with an embodiment of the present invention;

FIG. 11 is a diagram of the test of the return loss S22-S99 of the dual-band one-eight power divider 26GHz in the embodiment of the present invention;

FIG. 12 is a diagram of the test of the 4.9GHz insertion loss S21-S91 of the dual-band one-eight power divider in the embodiment of the present invention;

FIG. 13 is a graph of the dual band one-to-eight power divider 26GHz insertion loss S21-S91 in an embodiment of the present invention;

fig. 14 is a diagram illustrating an isolation test between 4.9GHz output ports of a dual-band one-to-eight power divider according to an embodiment of the present invention;

fig. 15 is a graph illustrating an isolation diagram between the output ports of the dual-band one-to-eight power divider 26GHz according to an embodiment of the present invention;

fig. 16 is a phase test diagram of the 4.9GHz output port of the dual-band one-eight power divider according to the embodiment of the present invention;

fig. 17 is a phase test diagram of the 26GHz output port of the dual-band one-eight power divider according to the embodiment of the present invention.

Detailed Description

The technical solutions of the present invention will be described in further detail with reference to the accompanying drawings and examples, and it is obvious that the described examples are some, but not all, examples of the present invention, and the embodiments of the present invention are not limited thereto. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The utility model is mainly used in the technical field of radio, can be applied to a radio frequency communication system of double-frequency bands of Sub-6GHz and millimeter wave of 5G mobile communication, and can be used as a multi-port power divider particularly in a large-scale array antenna with a plurality of ports.

Examples

The embodiment provides a dual-frequency low-insertion-loss miniaturized one-to-eight power divider with a double-section impedance transformation microstrip line and two isolation resistors, the dual-frequency band work with a high frequency ratio can be realized by reasonably designing the length and the width of the microstrip line, the structure and the size of a chip resistor, the insertion loss is low, the isolation degree of each port is high, and the whole size is small.

As shown in fig. 1 to 3, the millimeter wave dual-band power divider of this embodiment includes a dielectric sheet 1, a copper sheet 4, a plurality of female connectors 2, and a plurality of one-to-two microstrip structures 3 disposed on the dielectric sheet 1. The plurality of one-to-two microstrip structures 3 are connected to form a multi-stage power distribution unit, an input end of the one-to-two microstrip structure located in the first-stage power distribution unit is an input port of the millimeter wave dual-band power divider of this embodiment, and output ends of the plurality of one-to-two microstrip structures located in the last-stage power distribution unit are a plurality of output ports of the millimeter wave dual-band power divider of this embodiment. The plurality of female connectors 2 are respectively disposed at the input port and the plurality of output ports of the millimeter wave dual-band power divider of this embodiment. Copper sheet 4 is a 1 ounce thick sheet of copper that is placed immediately beneath the media sheet 1. The copper sheet 4 is used as the grounding surface of the integral 1-in-8 dual-frequency power divider and is welded with the outer layer metal of the 2.92mm female connector. Each one-to-two microstrip structure 3 has the same structure and includes a first transmission microstrip line 301, an impedance transformation microstrip line 302 and a chip resistor 303, wherein the first transmission microstrip line 301 is located at the input end of the one-to-two microstrip structure, the chip resistor 303 is located above the tail end of the impedance transformation microstrip line 302, and the output end of the one-to-two microstrip structure is led out from the tail end of the impedance transformation microstrip line 302. Two one-to-two microstrip structures 3 of two adjacent stages are connected through a second transmission microstrip line, and the final-stage power distribution unit is also connected with the output port of the millimeter wave dual-band power divider through the second transmission microstrip line. In this embodiment, the millimeter wave dual-band power divider is provided with three stages of power distribution units, the formed one-to-eight power divider is integrally symmetric about a symmetric axis 316, the one-stage one-to-two microstrip structure includes one-to-two microstrip structure, the two-stage one-to-two microstrip structure includes two-to-two microstrip structures, the three-stage one-to-two microstrip structure includes four-to-two microstrip structures, the first stage power distribution unit is connected with the one-to-two microstrip structure of the second stage power distribution unit through a second transmission microstrip line 304-.

In this embodiment, the first transmission microstrip line 301, the second transmission microstrip line 304, the impedance transformation microstrip line 302 are all implemented by copper-clad microstrip lines, and the transmission microstrip line and the impedance transformation microstrip line all belong to copper microstrip lines, but the characteristic impedances are different. The impedance transformation microstrip line 302 of the one-in-two microstrip structure 3 is a double-section impedance transformation microstrip line which is used for double-frequency-band impedance matching and can generate resonance points in two frequency bands; each section of the impedance transformation microstrip line is pasted with a chip resistor which plays an isolation role and is bridged at the tail end of the two sections of the impedance transformation microstrip lines, a certain isolation degree is kept between two output ports, mutual coupling is reduced, and the two chip resistors can adopt resistors with different resistance values, preferably 0402 chip resistor. The female connector is preferably a 2.92mm female connector, and the three-stage power distribution unit has one input port and 8 output ports in common, so that the present embodiment is provided with 9 female connectors.

In this embodiment, because a certain degree of isolation must be ensured for eight channels of the one-to-eight power divider, chip resistors R1 and R2 for isolation are welded at the ends of the upper and lower two sections of impedance transformation microstrip lines in each group of two-to-one microstrip structure, and cross over the upper surface of the upper and lower two sections of impedance transformation microstrip lines, so that a total of 7 groups of chip resistors R1 and R2 need to be welded.

The principle of power distribution in this embodiment is as follows: the first transmission microstrip line 301 equally divides energy to the second

transmission microstrip lines

304 and 305 through the two sections of impedance transformation microstrip lines 302 and the two 0402 chip resistors 303, the second transmission microstrip line 304 equally divides self power to the second

transmission microstrip lines

306 and 307 through the two sections of impedance transformation microstrip lines and the two 0402 chip resistors, and similarly, the second

transmission microstrip lines

306 and 307 also equally divide self power to the second

transmission microstrip lines

308 and 311 respectively. At this time, the overall effect appears as 1-in-4 power division from the second transmission microstrip line 304. The one-to-eight power divider of this embodiment is symmetrical about the symmetry axis 316, and the upper and lower portions are completely symmetrical. Therefore, the second transmission microstrip line 305 can also perform 1-to-4 power division as well as the second transmission microstrip line 304. Finally, the total energy enters from the first transmission microstrip line 301 and flows out from the second transmission microstrip line 308-. In each one-to-two microstrip structure, the two impedance conversion microstrip lines have a dual-band impedance matching function and can generate resonance points in two frequency bands, and the two 0402 chip resistors have an isolation function, so that a certain isolation degree is kept between two output ports, and mutual coupling is reduced.

An equivalent circuit of a one-to-eight power divider is shown in FIG. 4, and the impedance can be calculated by the transmission line basic theory and the odd-even mode analysis methodanti-Z₁、Z₂Length l of microstrip line₁、l₂And the magnitude of the resistance values R1, R2:

1. s parameter analysis

For an one-to-eight power divider, we require that its S parameter satisfies:

S₁₁＝S₂₂＝S₃₃＝S₄₄＝S₅₅＝S₆₆＝S₇₇＝S₈₈＝S₉₉＝0

S₂₁＝S₃₁＝S₄₁＝S₅₁＝S₆₁＝S₇₁＝S₈₁＝S₉₁

S_ij＝0，i、j≠1，i≠j

S₁₁to S₉₉I.e. S_ij0, j, indicating that the 9 ports are impedance matched and that the energy transfer is not reflected. S₂₁To S₉₁I.e. S_i1I ≠ 1, which represents the insertion loss of the energy transmission incident from the 1 port to each output port, and the values are equal due to reciprocity. S_ij0, i, j ≠ 1, i ≠ j, S_ijRepresenting the degree of isolation between the two output ports i and j, where the value is zero, representing complete isolation between the two ports with no coupling.

2. Equivalent circuit analysis

Fig. 4 is an equivalent circuit diagram of an eight-to-one power divider. The one-to-eight power divider is designed on the basis of the theory of one-to-two power divider. For convenient design and understanding, the dual-band power divider is designed theoretically in a one-to-two power divider.

Taking a one-to-two wilkinson power divider as an example, the present embodiment adopts a structure of a dual-section impedance transformation microstrip line and two isolation patch resistors to construct a dual-frequency wilkinson power divider, as shown in fig. 5.

Wherein Z₀Is a characteristic impedance of 50 omega, and Z and l are the impedance and length of the impedance transformation microstrip line, respectively, wherein subscripts 1 and 2 represent a first section of the impedance transformation microstrip line and a second section of the impedance transformation microstrip line, respectively, and frequency f₁、f₂Respectively representing the operating frequencies (f) of the dual-frequency power divider₂＞f₁). And performing odd-mode and even-mode analysis on the Wilkinson power divider.

And (3) even mode analysis:

fig. 6 shows the even-mode analysis of the one-to-two power divider:

let Z_П ^ev＝Z₀The content of beta and l can be obtained₁、l₂Z of variable₁And Z₂. Wherein

The variable β is a propagation constant, related to the operating frequency f. l₁、l₂Value of (d) and frequency of operation f₁And f₂It is related. u is the frequency ratio and is f₁And f₂The ratio therebetween.

β₁l₁±β₂l₁＝nπ

β₁l₂±β₂l₂＝mπ

Wherein n and m are any positive integer.

Here, the present embodiment is a dual-band power divider for 4.9GHz and 26GHz, so here u ≈ 5.3.

And (3) odd mode analysis:

fig. 7 shows the odd-mode analysis of the one-to-two power divider:

Z_I ^od＝jZ₁tan(βl₁)

let Z_Ⅳ ^od＝Z₀While beta, l are known from even-mode analysis₁、l₂、Z₁And Z₂Finally, R can be obtained₁And R₂。

3. Low insertion loss and miniaturization analysis

Secondly, to achieve low-cost millimeter wave performance, a microstrip line length that reduces one-to-eight of the whole must be designed, so according to the formula:

let us order Z₁Less than Z₂Thus there must be:

in order to establish the formula, tan (. beta.l) must be present₁) With tan (. beta.l)₂) While the value is relatively small.

Then according to the formula:

β₁l₁±β₂l₁＝nπ

β₁l₂±β₂l₂＝mπ

these two equations take the positive sign:

β₁l₁+β₂l₁＝nπ

β₁l₂+β₂l₂＝mπ

wherein, beta₁、β₂The propagation constants are respectively the propagation constant of the first working frequency and the propagation constant of the second working frequency of the dual-frequency power divider, and the propagation constants are determined according to two working frequencies of the dual-frequency power divider to be obtained. In this way, a smaller first-section impedance transformation microstrip line length l can be obtained₁And a second length l of impedance transformation microstrip line₂The length of the microstrip line can be greatly reduced, so that the insertion loss of the power divider can be greatly reduced, and the size of the power divider is also reduced. By calculating and considering the coupling factor influence brought by the compressed size, the following design parameters can be obtained finally:

l₁＝4.6mm，l₂＝5.9mm，Z₁＝65Ω，Z₂＝80Ω，Z₀＝50Ω，R₁130 Ω and R₂＝70Ω。

Wherein Z is₁Is the impedance of the first section of the impedance transforming microstrip line, Z₂Is the impedance of the second section of the impedance transforming microstrip line, R₁、R₂Respectively, the resistance values of the two isolation resistors.

And then, through ADS (automatic device specification) software, the structural design of the millimeter wave dual-band power divider is carried out, and the length and the width of the microstrip line and the size of the chip resistor are adjusted and optimized. Meanwhile, the microstrip line distribution of the double-section impedance is reasonably designed, so that the size of the power divider can be greatly reduced, and the miniaturization result is achieved. In the two-section impedance matching circuit determining the double-frequency operation, the length W6 of the two-section impedance matching is compressed to 6.2mm in a compression compact mode. Thus, a one-to-eight power divider with double frequency, low insertion loss and miniaturization can be achieved.

In addition, this embodiment still rationally designs medium piece thickness. Because of the relation between the microstrip line transmission impedance and the plate, the plate is thinner, but the plate can directly use a domestic high-frequency plate F4B with the thickness of 0.5mm and the relative dielectric constant of 2.55 without manufacturing a metal shell for packaging. Thus can even makeThe microstrip line has small width and small insertion loss, and the board can have certain thickness and is convenient for direct application. After the thickness and the type of the dielectric sheet are determined, the impedance Z of the microstrip line is converted according to the calculated first section impedance₁65 omega, the second section impedance transformation microstrip line impedance Z₂Microstrip line impedance calculation and analysis are carried out for 80 omega to obtain the microstrip line widths of the first section of impedance conversion microstrip line and the second section of impedance conversion microstrip line, and Z can be obtained₁The width W2 of 65 omega microstrip line is 0.74mm, Z₂The width W3 of the 80 Ω microstrip line is 0.5 mm; with Z being₀The 50 Ω microstrip line width W1 corresponds to 1.17 mm.

In addition to reducing the length of the microstrip line, the present embodiment optimizes the structural distribution of the power divider, and compresses the length W6 of the two-section impedance matching to 6.2mm in a compact compression manner in the two-section impedance matching circuit that determines the dual-frequency operation.

Preferably, in the one-eight power divider, as shown in fig. 2, W1-1.17 mm, W2-0.74 mm, W3-0.5 mm, W4-0.6 mm, W5-13.6 mm, W6-6.2 mm, l₁＝4.6mm，l₂5.9mm, 130 Ω for R1 and 70 Ω for R2. Then, according to the one-to-eight equivalent circuit diagram shown in fig. 4, a plurality of one-to-two structures are connected together, so that the one-to-eight power divider with dual frequency, low insertion loss and miniaturization can be achieved.

Meanwhile, in order to obtain higher port isolation, two chip resistors are added into each one-to-two microstrip structure, and the isolation between ports is improved in a mode of 14 chip resistors in the whole one-to-eight power divider. The microstrip line between the two sections of impedance matching circuits requires a smaller distance, so that the distribution parameter effect caused by millimeter waves can be solved by matching with the 0402 chip resistor with the length of only 1 mm. Therefore, the port can be controlled to have higher isolation, and the performance of the dual-frequency power divider is improved.

The performance test result of the microwave and millimeter wave dual-band one-to-eight power divider of this embodiment is shown in fig. 8-17, and the one-to-eight power divider can be used in a 4.9GHz band (1090 MHz bandwidth), S11 < -20dB, return loss of an output port < -15dB, isolation between output ports > 19.3dB, and insertion loss between-9.25 dB and-9.29 dB. The amplitude difference between the 8 output ports is less than 0.04dB, and the phase difference is less than 0.5 degrees; in a 26GHz frequency band (with a bandwidth of 390MHz), S11 is less than-15 dB, the return loss of an output port is less than-16 dB, the isolation between the output ports is more than 20dB, and the insertion loss is between-12 and-12.8 dB. The amplitude difference between the 8 output ports is less than 0.8dB, and the phase difference is less than 3.8 degrees.

After the structure and the length of the one-to-eight power divider are optimally designed, the whole miniaturization is realized, the transverse dimension of the one-to-eight power divider is 30.3 multiplied by 108.8mm, and the thickness of the one-to-eight power divider is 0.5 mm; because the miniaturization technology shortens the length of the microstrip line, and other loss components are not added except for the isolation patch resistor, the dual-frequency insertion loss is lower, the insertion loss of the 4.9GHz frequency band is 9.25-9.29dB, and the insertion loss of the millimeter wave frequency band is only 12-12.8 dB.

Based on the same inventive concept, the design method of the millimeter wave dual-band power divider of the embodiment includes the following steps:

on the basis of the one-to-two power divider, a double-section impedance transformation microstrip line and two isolation resistors are adopted to construct the double-frequency one-to-two power divider as a one-to-two microstrip structure, and a plurality of one-to-two microstrip structures are further obtained;

connecting a plurality of one-to-two microstrip structures to form a multi-stage power distribution unit;

the impedance and the length of a first section of impedance transformation microstrip line and a second section of impedance transformation microstrip line in the two sections of impedance transformation microstrip lines are calculated by performing even mode and odd mode analysis and low insertion loss and miniaturization analysis on the one-to-two power divider, so that the length of the microstrip line of the whole millimeter wave dual-band power divider is reduced, and the size of the whole millimeter wave dual-band power divider is reduced; the impedance and length calculation relationship of the first section of impedance transformation microstrip line and the second section of impedance transformation microstrip line is as follows:

β₁l₁+β₂l₁＝nπ

β₁l₂+β₂l₂＝mπ

l₁、l₂a first section of impedance transformation microstrip line and a second section of impedance transformationChanging the length of the microstrip line; beta is a₁、β₂Respectively is the propagation constant of the first working frequency and the propagation constant of the second working frequency of the double-frequency power divider; n and m are any positive integer;

the structural design of the millimeter wave dual-band power divider is carried out, the length and the width of a microstrip line and the size of an isolation resistor are adjusted and optimized, and the distribution of the microstrip line of a double-section impedance transformation microstrip line is designed;

and determining the thickness and the type of the dielectric sheet, and performing calculation analysis on the microstrip line impedance according to the calculated first section of impedance transformation microstrip line impedance and the calculated second section of impedance transformation microstrip line impedance to obtain the microstrip line widths of the first section of impedance transformation microstrip line and the second section of impedance transformation microstrip line.

In addition to the way mentioned in this embodiment, the following changes can be made: the 0402 chip resistor can be replaced by other types of chip resistors or even film resistors, and the connector can also be other types of connectors. Meanwhile, the type of the plate can be changed by the medium sheet, and the size of the whole plate can be adjusted.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. The low-insertion-loss miniaturized millimeter wave dual-band power divider with high frequency ratio is characterized by comprising a dielectric sheet and a plurality of one-to-two microstrip structures arranged on the dielectric sheet; the multiple one-to-two microstrip structures are connected to form a multi-stage power distribution unit, the input end of the one-to-two microstrip structure positioned in the first-stage power distribution unit is an input port of the millimeter wave dual-band power divider, and the output ends of the multiple one-to-two microstrip structures positioned in the last-stage power distribution unit are multiple output ports of the millimeter wave dual-band power divider; two one-to-two microstrip structures of two adjacent stages are connected through a second transmission microstrip line.

2. The millimeter wave dual-band power divider according to claim 1, wherein the one-to-two microstrip structure comprises a first transmission microstrip line, an impedance transformation microstrip line and an isolation resistor, wherein the first transmission microstrip line is located at an input end of the one-to-two microstrip structure, the isolation resistor is bridged at a tail end of the impedance transformation microstrip line, and an output end of the one-to-two microstrip structure is led out from the tail end of the impedance transformation microstrip line.

3. The millimeter wave dual-band power divider according to claim 2, wherein the last power distribution unit is also connected to the output port of the millimeter wave dual-band power divider through a second microstrip transmission line.

4. The millimeter wave dual-band power divider according to claim 2, wherein the first transmission microstrip line, the second transmission microstrip line and the impedance transformation microstrip line are all copper-clad microstrip lines.

5. The millimeter wave dual-band power divider according to claim 2, wherein the impedance transformation microstrip line is a dual-section impedance transformation microstrip line, and each section of the impedance transformation microstrip line is provided with an isolation resistor.

6. The millimeter wave dual-band power divider according to claim 1, wherein the millimeter wave dual-band power divider is provided with three stages of power distribution units, the one-to-eight power divider is formed as a symmetrical structure as a whole, the one-to-two microstrip structure at the first stage comprises a one-to-two microstrip structure, the two-stage one-to-two microstrip structure comprises two-to-two microstrip structures, and the three-stage one-to-two microstrip structure comprises four one-to-two microstrip structures.

7. The millimeter wave dual-band power divider according to any one of claims 2 to 5, wherein the isolation resistor is a chip resistor.

8. The millimeter wave dual-band power divider according to any one of claims 2 to 6, wherein the millimeter wave dual-band power divider further comprises a copper sheet and a plurality of female connectors, and the plurality of female connectors are respectively disposed at an input port and a plurality of output ports of the millimeter wave dual-band power divider; the copper sheet is closely attached to the lower surface of the medium sheet, and the outer layer metal of the female connector is connected with the copper sheet.

9. The millimeter wave dual-band power divider according to claim 1, wherein two chip resistors are added as isolation resistors in a one-to-two microstrip structure at each point.

10. The millimeter wave dual band power divider according to any one of claims 2-5 and 9, wherein the length of the isolation resistor is 1 mm.