WO2021082293A1

WO2021082293A1 - Miniaturized e-plane coupler having slow-wave half-mode substrate integrated waveguide

Info

Publication number: WO2021082293A1
Application number: PCT/CN2020/072978
Authority: WO
Inventors: 刘水; 许锋
Original assignee: 南京邮电大学
Priority date: 2019-10-28
Filing date: 2020-01-19
Publication date: 2021-05-06
Also published as: CN110752430A; CN110752430B

Abstract

Disclosed is a miniaturized E-plane coupler having a slow-wave half-mode substrate integrated waveguide, comprising upper and lower layers of slow-wave half-mode substrate integrated waveguides which are stackingly placed and coupling structures thereof. The coupler introduces a slow wave effect on the basis of a common E-plane coupler, and uses the slow wave effect to further reduce the volume of the coupler. Meanwhile, the present invention cleverly combines the slow wave effect with coupling, and no additional loss to the coupler is caused due to the introduction of the slow wave effect. Therefore, the present invention is particularly suitable for strong coupling couplers which have higher miniaturization requirements. Specifically, the present invention achieves a 3-dB working bandwidth of 45% within a smaller volume; moreover, insertion loss within a working frequency band is low, phase quadrature is stable, fabrication is simple and costs are low. In comparison to existing H-plane slow-wave couplers, the present invention fills the gap in the field of substrate integrated waveguides in which E-plane slow-wave couplers do not exist and greatly broadens the application prospects of the coupler in aspects such as miniaturization and dual-polarized antennas.

Description

Miniaturized slow-wave half-mode substrate integrated waveguide E-plane coupler

Technical field

The invention relates to a miniaturized slow-wave half-mode substrate integrated waveguide E-plane coupler, which can be used in the field of microwave technology.

Background technique

With the rapid development of communication technology, people have put forward more requirements for the miniaturization, broadband, and multi-polarization of communication systems. The coupler has a wide range of applications in the field of microwave technology because it is easy to realize the power division effect of any power. As a core device, couplers are widely used in microwave wireless communication systems and radar detection systems. Among them, H-plane couplers are the most common because they can be realized by a single-layer circuit, and the design and implementation are relatively simple. However, in practical applications, the E-plane coupler has a smaller volume and more applications than the H-plane coupler, which is of great help to the improvement of the entire microwave and millimeter wave system.

The traditional substrate integrated waveguide is a fast-wave structure, and the coupling effect is mainly realized by opening holes in the wall of the common waveguide. Although the substrate-integrated waveguide pinhole coupler has a certain improvement compared with the previous three-dimensional metal waveguide structure, it still has the disadvantages of being large in a certain sense and not easy to integrate in the face of new requirements. Half-mode substrate integrated waveguide technology has made microwave devices have a broader development. The half-mode substrate integrated waveguide technology has the characteristics of small size, light weight, high quality factor, low insertion loss, high integration, and high power capacity. Compared with the substrate integrated waveguide, the circuit area is further reduced, and it is more conducive to the miniaturization of the circuit. design.

Recently, the newly proposed substrate integration technology combined with slow-wave technology further reduces the volume of the waveguide device and gives more options for coupler design. Since the H-plane slow-wave coupler is easy to realize in structure, there are many ways to realize it. Compared with the traditional fast-wave mode coupler, it has achieved a certain degree of miniaturization. The E-plane slow-wave coupler does not have a mature design due to the complexity of the structure and the influence of the performance, but its volume is smaller and the application prospect is broader, and it has very important research value.

Summary of the invention

The purpose of the present invention is to solve the above-mentioned problems in the prior art, and propose a miniaturized slow-wave half-mode substrate integrated waveguide E-plane coupler.

The purpose of the present invention will be achieved through the following technical solutions: a miniaturized slow-wave half-mode substrate integrated waveguide E-surface coupler, including a top dielectric substrate and a bottom dielectric substrate, the top dielectric substrate and the bottom dielectric substrate are stacked Place, the upper surface of the top dielectric substrate is provided with a top metal layer, an intermediate metal layer is provided between the top dielectric substrate and the bottom dielectric substrate, and a bottom metal layer is provided on the lower surface of the bottom dielectric substrate;

The top dielectric substrate and the bottom dielectric substrate are each provided with a row of metalized through holes, and the row of metalized through holes forms the first half-mode substrate integrated waveguide with the top metal layer, the top dielectric substrate, and the middle metal layer. The metallized through hole, the intermediate metal layer, the bottom dielectric substrate, and the bottom metal layer constitute the second half-mode substrate integrated waveguide.

Preferably, the upper surface of the top dielectric substrate is provided with two first microstrip lines and second microstrip lines respectively connected to both ends of the top metal layer of the first half-mode substrate integrated waveguide; the bottom dielectric substrate Two third microstrip lines and fourth microstrip lines respectively connected to the two ends of the bottom metal layer of the second half-mode substrate integrated waveguide are arranged on the bottom surface of the second half-mode substrate integrated waveguide.

Preferably, the first microstrip line, the second microstrip line, the third microstrip line and the fourth microstrip line respectively pass through the first impedance conversion structure, the second impedance conversion structure, and the second impedance conversion structure of a trapezoidal microstrip patch. The three-impedance conversion structure and the fourth impedance conversion structure are connected to the metal layer of the integrated waveguide of the half-mode substrate and serve as the input port, the through port, the coupling port and the isolation port of the coupler.

Preferably, the coupler has a symmetrical structure, the first microstrip line and the second microstrip line are arranged in the same layer, the first microstrip line is the input end of the coupler, the second microstrip line is the through port, and the second microstrip line is the through port. The three microstrip lines and the first microstrip line are arranged in different layers on the same side, the third microstrip line is an isolated end, and the fourth microstrip line and the second microstrip line are arranged in different layers on the same side.

Preferably, the impedances of the first microstrip line, the second microstrip line, the third microstrip line and the fourth microstrip line are all 50 ohms.

Preferably, a row of complementary open resonant rings is provided on the intermediate metal layer, and the complementary open resonant ring includes at least two rectangular open annular grooves with opposite openings.

Preferably, the row of complementary open resonant rings and a row of metalized through holes are arranged in parallel with a gap, and the spacing between every two adjacent complementary open resonant rings is equal.

Preferably, the number of a row of complementary open resonant rings on the metal layer of the intermediate layer is N, and the value of N is ≥3.

Preferably, the top dielectric substrate and the bottom dielectric substrate are both Rogers 5880 dielectric plates, and the dielectric constant is 2.2.

Preferably, the thickness of each layer of the top dielectric substrate and the bottom dielectric substrate is 0.5 mm.

Compared with the prior art, the above technical solution has the following technical effects: the technical solution is based on the traditional fast wave HMSIW planar coupler structure, and overcomes the large three-dimensional structure of the traditional waveguide coupler, which is difficult to integrate. It has important application value in chemistry. At the same time, the present invention realizes the slow wave effect on the HMSIW by etching the complementary split resonant ring structure in the HMSIW and applies it to the design of the E-plane coupler, and uses the slow wave effect to further reduce the volume of the coupler; at the same time cleverly The complementary split resonant ring is used as the coupling hole between the double-layer circuits to avoid introducing additional slow-wave structures, simplifying the circuit, and achieving the purpose of improving the performance of the coupler. In the slow wave mode, the coupler has more stable performance and smaller size.

The invention expands the application of the miniaturized slow-wave half-mode substrate integrated waveguide E-plane coupler in the future miniaturization, broadband, multi-polarization microwave millimeter wave circuit integration by studying the planarized E-plane slow-wave coupler.

The invention has simple design structure and large 3-dB coupling working bandwidth. Compared with traditional three-dimensional and multilayer structure couplers, its double-layer structure is more suitable for modern microwave and millimeter wave circuit integration; meanwhile, it adopts half-mode substrate integrated waveguide Technology, the structure is very compact, which reduces the processing difficulty and reduces the processing cost.

The invention integrates the slow-wave effect into the coupler. Compared with the traditional fast-wave coupler technology, the invention has the advantages of small size and low insertion loss, which fills the gap in the research of the slow-wave E-surface coupler. Compared with the relatively mature slow-wave H-plane coupler technology that is currently internationally studied, the present invention realizes the energy coupling of the E-plane between slow-wave transmission lines for the first time. At the same time, compared with the H-plane coupling single-layer circuit, the volume is smaller and the application is also Wider.

Description of the drawings

Fig. 1 is a schematic diagram of a double-layer half-mode substrate integrated waveguide of the present invention.

2 is a schematic diagram of the structure of a complementary split resonant ring etched on the metal layer of the intermediate layer of the present invention.

3 is a schematic diagram of the three-dimensional structure of the miniaturized slow-wave half-mode substrate integrated waveguide E-plane coupler of the present invention.

Fig. 4 is a three-dimensional sectional view of the miniaturized slow-wave half-mode substrate integrated waveguide E-plane coupler of the present invention.

Fig. 5 is a top view of the miniaturized slow-wave half-mode substrate integrated waveguide E-plane coupler of the present invention.

Fig. 6 is the S parameter simulation result of the coupler of the present invention.

Fig. 7 is the actual measurement result of the S parameter of the coupler of the present invention.

Fig. 8 is a comparison between simulation and actual measurement results of the phase difference between the through end and the coupling end of the coupler of the present invention.

Detailed ways

The purpose, advantages and characteristics of the present invention will be illustrated and explained through the following non-limiting description of preferred embodiments. These embodiments are only typical examples of applying the technical solutions of the present invention, and any technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of protection claimed by the present invention.

The present invention discloses a miniaturized slow-wave half-mode substrate integrated waveguide E-surface coupler, as shown in Figure 1, Figure 2, Figure 3, Figure 4 and Figure 5, comprising a top dielectric substrate 2 and a bottom dielectric substrate 3. The top dielectric substrate 2 and the bottom dielectric substrate 3 are stacked.

The upper surface of the top dielectric substrate 2 is provided with a top metal layer 6, an intermediate metal layer 5 is provided between the top dielectric substrate 2 and the bottom dielectric substrate 3, and the bottom surface of the bottom dielectric substrate 3 is provided with a bottom metal layer. Layer 7.

Each of the top dielectric substrate 2 and the bottom dielectric substrate 3 is provided with a row of metallized through holes 1, and the row of metalized through holes 1 and the top metal layer 6, the top dielectric substrate 2, the middle metal layer 5 constitute a second The half-mode substrate integrated waveguide, the row of metallized through holes 1 and the intermediate metal layer 5, the bottom dielectric substrate 3, and the bottom metal layer 7 constitute a second half-mode substrate integrated waveguide.

The upper surface of the top dielectric substrate 2 is provided with two first microstrip lines 12 and second microstrip lines 15 respectively connected to the two ends of the top metal layer of the first half-mode substrate integrated waveguide; the bottom dielectric substrate The lower surface of 3 is provided with two third microstrip lines 13 and fourth microstrip lines 14 respectively connected to the two ends of the bottom metal layer of the second half-mode substrate integrated waveguide.

The first microstrip line 12, the second microstrip line 15, the third microstrip line 13, and the fourth microstrip line 14 respectively pass through a first impedance conversion structure 8 and a second impedance conversion structure of a trapezoidal microstrip patch 9. The third impedance conversion structure 10 and the fourth impedance conversion structure 11 are connected to the metal layer of the integrated waveguide of the half-mode substrate and serve as the input port, the through port, the coupling port and the isolation port of the coupler.

The first microstrip line 12 and the second microstrip line 15 are arranged in the same layer, the first microstrip line 12 is the input end of the coupler, the second microstrip line 15 is a through port, and the third microstrip line 13 is connected to the The first microstrip line 12 is arranged in different layers on the same side, the third microstrip line 13 is an isolated end, and the fourth microstrip line 14 and the second microstrip line 15 are arranged in different layers on the same side. The coupler has a symmetrical structure. If the input port changes, the remaining ports refer to the above distribution and so on.

The impedances of the first microstrip line 12, the second microstrip line 15, the third microstrip line 13 and the fourth microstrip line 14 are all 50 ohms. The middle metal layer 5 is provided with a row of complementary open resonant rings 4, and the complementary open resonant ring 4 includes at least two rectangular open annular grooves with opposite openings.

The row of complementary open resonant rings 4 and a row of metallized through holes 1 are arranged in parallel with gaps, and the spacing between every two adjacent complementary open resonant rings 4 is equal. The center position of the complementary split resonant ring 4 on the intermediate metal layer 7 has a certain influence on the performance and size of the coupler, and its best position is located above the center of the integrated waveguide of the half-mode substrate.

The number of a row of complementary split resonant rings 4 on the intermediate metal layer 7 is N, and the value of N is ≥3. The first half-mode substrate integrated waveguide and the second half-mode substrate integrated waveguide are aligned up and down. As shown in Figure 3, the double-layer half-mode substrate integrated waveguide includes the top metal layer, dielectric substrate, The middle metal layer, the dielectric substrate and the bottom metal layer have a row of metalized through holes evenly distributed on the long sides of the first half-mode substrate integrated waveguide and the second half-mode substrate integrated waveguide. The top metal layer, the middle metal layer and the bottom metal layer are all made of copper. The first half-mode substrate integrated waveguide and the second half-mode substrate integrated waveguide are closely stacked and share the middle metal layer to form a double-layer board circuit. .

Each layer of half-mode substrate integrated waveguide is built on a piece of dielectric substrate. The upper and lower surfaces of the dielectric substrate are covered with metal layers. There is a row of metalized through holes inside the dielectric substrate. All structures on the dielectric substrate together form a layer of half-mode substrate. Integrated waveguide. The top dielectric substrate 2 and the bottom dielectric substrate 3 are both Rogers 5880 dielectric plates with a dielectric constant of 2.2, and the thickness of each layer of the top dielectric substrate 2 and the bottom dielectric substrate 3 is 0.5 mm.

As shown in Figures 4 and 5, three complementary open resonant rings are etched on the metal layer of the middle layer to form a slow wave structure, and the slow wave effect is simultaneously introduced into the upper and lower half-mode substrate integrated waveguides; at the same time, complementary open resonant rings It can also be considered as a hole opened on the common surface of the double-layer half-mode substrate integrated waveguide, and the energy in the upper and lower half-mode substrate integrated waveguides is coupled through the complementary open resonant ring.

In the coupler of the present invention, the complementary split resonant ring is placed approximately at the center of the integrated waveguide of the entire half-mode substrate on the basis of maintaining a fixed interval, so as to achieve the optimal slow-wave effect and coupling effect. Four microstrip lines are respectively connected to the two ends of the integrated waveguide of the two half-mode substrates as the input end, the through end, the coupling end and the isolation end of the coupler. The four microstrip lines and the half-mode substrate integrated waveguide are connected by a trapezoidal microstrip patch to achieve impedance matching, and the impedance of the four microstrip lines are all 50 ohms.

Fig. 6 and Fig. 7 are the simulation and actual measurement results of the coupler of the present invention. The abscissa of Fig. 6 and Fig. 7 both represent the frequency, and the ordinate both represent the S-parameter performance of the coupler. From the results of Fig. 6 and Fig. 7, it can be seen that the measured 3-dB coupling bandwidth of the coupler of the present invention is 6.2 GHz-10 GHz, the center frequency is 8.1 GHz, and the relative bandwidth is 45%. The return loss of the input port is greater than 20dB, and the isolation between the input end and the isolation end is more than 20dB, and the isolation effect is very good.

Fig. 8 is the simulation and actual measurement results of the phase difference between the through port and the coupling port of the present invention, where the abscissa represents the frequency, and the ordinate represents the phase difference. From the simulation results in Fig. 8, it can be seen that the phase difference between the through end and the coupling end in the working frequency band is 88°±3° (90° is normal orthogonality), and the measured results are basically consistent with the simulation results, satisfying the 3-dB coupling Quadrature output requirements of the converter.

The present invention realizes the double-layer E-plane coupler in the slow wave mode for the first time, and realizes the combination of the slow-wave effect and the E-plane coupling technology, and achieves 3-dB broadband slow-wave coupling with only three complementary split resonant rings in a single row The effect; the complementary split resonant ring on the metal layer of the middle layer introduces the slow wave effect in the integrated waveguide of the upper and lower half-mode substrates, and at the same time, the coupling hole as a coupler participates in the energy coupling between the upper and lower layers.

The present invention utilizes a complementary split resonant ring structure to introduce a slow wave effect, which helps to further reduce the number of coupling holes, thereby achieving the purpose of miniaturization of the coupler. At the same time, the complementary split resonant ring itself can also be used as the coupling hole of the coupler. , Reducing the extra insertion loss of the slow wave effect to the coupler structure. The coupler of the invention realizes a 45% 3-dB working bandwidth in a smaller volume, and has stable performance in the working frequency band. Compared with the more common H-plane slow-wave coupler, the application prospects of the coupler in miniaturization and dual polarization are greatly expanded.

The size of the complementary split resonant ring affects both the slow wave effect of HMSIW and the coupling energy of the coupler. The larger the size of the complementary split resonant ring, the greater the slow wave effect, the higher the coupling energy, and the smaller the volume of the coupler. .

Among them, the half-mode substrate integrated waveguide is realized by designing a series of metalized through holes on the dielectric substrate. The size of the half-mode substrate integrated waveguide, the size of the metalized through hole and the distance between the through holes are determined by the working frequency band. Decided. The invention can smoothly realize the 3-dB energy coupling between the two layers of half-mode substrate integrated waveguides working in the slow wave mode, and at the same time realize the 90° phase shift between the through end and the coupling end, which is compared with the current common The H-plane coupler based on slow wave technology has a smaller volume and a wider application.

The invention has compact structure, superior performance, easy processing and integration, realizes the planarization of circuits and the integration of multilayer hybrid circuits, and is used in microwave and millimeter wave circuits and systems that require strict miniaturization, broadbandization, and multi-polarization. , Has a broader application prospect.

The present invention etches a row of complementary split resonant rings in the middle common metal layer of the half-mode substrate integrated waveguide to introduce the slow wave effect, and at the same time achieves the purpose of E-plane coupling, and finally realizes the small-volume wide-band strong coupling effect; The die-substrate integrated waveguide is realized by designing a series of metal vias on the printed circuit board.

The invention can smoothly realize the performance of a broadband and strong coupling E-plane coupler and achieve orthogonal output; more importantly, the invention has a good slow wave effect. Compared with the substrate integrated waveguide coupler of the same technology, the structure of the present invention is more compact. Compared with the existing slow wave coupler, the application of the coupler in the multi-polarization system is expanded, the volume is smaller, the insertion loss is lower, the manufacturing process is simple, and the cost is low.

There are many embodiments of the present invention, and all technical solutions formed by equivalent transformations or equivalent transformations fall within the protection scope of the present invention.

Claims

The miniaturized slow-wave half-mode substrate integrated waveguide E-surface coupler is characterized in that it comprises a top layer dielectric substrate (2) and a bottom layer dielectric substrate (3), the top layer dielectric substrate (2) and the bottom layer medium The substrates (3) are stacked,

The upper surface of the top dielectric substrate (2) is provided with a top metal layer (6), an intermediate metal layer (5) is provided between the top dielectric substrate (2) and the bottom dielectric substrate (3), and the bottom layer The bottom surface of the dielectric substrate (3) is provided with a bottom metal layer (7);

The top dielectric substrate (2) and the bottom dielectric substrate (3) are each provided with a row of metalized through holes (1), and the row of metalized through holes (1) is connected to the top metal layer (6) and the top dielectric The substrate (2) and the intermediate metal layer (5) constitute the first half-mode substrate integrated waveguide, and the row of metallized through holes (1) are connected with the intermediate metal layer (5), the bottom dielectric substrate (3), and the bottom layer. The metal layer (7) constitutes the second half-mode substrate integrated waveguide.
The miniaturized slow-wave half-mode substrate integrated waveguide E-surface coupler according to claim 1, characterized in that: the upper surface of the top layer dielectric substrate (2) is provided with two pairs of The first microstrip line (12) and the second microstrip line (15) connected at the two ends of the top metal layer of the integrated waveguide; the bottom surface of the bottom dielectric substrate (3) is provided with two second half-modes respectively The third microstrip line (13) and the fourth microstrip line (14) are connected at both ends of the bottom metal layer of the substrate integrated waveguide.
The miniaturized slow-wave half-mode substrate integrated waveguide E-plane coupler according to claim 2, characterized in that: the first microstrip line (12), the second microstrip line (15), and the third microstrip line The line (13) and the fourth microstrip line (14) respectively pass through the first impedance conversion structure (8), the second impedance conversion structure (9), the third impedance conversion structure (10), and the second impedance conversion structure of a trapezoidal microstrip patch. The four-impedance conversion structure (11) is connected with the metal layer of the integrated waveguide of the half-mode substrate and serves as the input port, the through port, the coupling port and the isolation port of the coupler.
The miniaturized slow-wave half-mode substrate integrated waveguide E-plane coupler according to claim 3, characterized in that: the coupler has a symmetric structure, and the first microstrip line (12) and the second microstrip line ( 15) is set in the same layer, the first microstrip line (12) is the input end of the coupler, the second microstrip line (15) is the through port, and the third microstrip line (13) is the same as the first microstrip line (12). ) Is set in different layers on the same side, the third microstrip line (13) is an isolated end, and the fourth microstrip line (14) and the second microstrip line (15) are set in different layers on the same side.
The miniaturized slow-wave half-mode substrate integrated waveguide E-plane coupler according to claim 3, characterized in that: the first microstrip line (12), the second microstrip line (15), and the third microstrip line The impedance of the line (13) and the fourth microstrip line (14) are both 50 ohms.
The miniaturized slow-wave half-mode substrate integrated waveguide E-plane coupler according to claim 1, characterized in that: the middle metal layer (5) is provided with a row of complementary open resonant rings (4), and the complementary open resonant The ring (4) includes at least two rectangular open annular grooves with opposite openings.
The miniaturized slow-wave half-mode substrate integrated waveguide E-plane coupler according to claim 6, characterized in that: the row of complementary open resonant rings (4) and a row of metalized through holes (1) are arranged in parallel with gaps , And the spacing between every two adjacent complementary open resonant rings (4) is equal.
The miniaturized slow-wave half-mode substrate integrated waveguide E-plane coupler according to claim 6, characterized in that the number of a row of complementary split resonant rings (4) on the intermediate metal layer (7) is N, The value of N is ≥3.
The miniaturized slow-wave half-mode substrate integrated waveguide E-plane coupler according to claim 1, characterized in that: the upper dielectric substrate (2) and the bottom dielectric substrate (3) are both Rogers 5880 dielectric plates , The dielectric constant is 2.2.
The miniaturized slow-wave half-mode substrate integrated waveguide E-surface coupler according to claim 9, characterized in that: the thickness of each layer of the upper dielectric substrate (2) and the bottom dielectric substrate (3) is 0.5 Mm.