CN108777343A - Substrate integration wave-guide transmission structure, antenna structure and connection method - Google Patents

Abstract

The invention discloses a substrate-integrated waveguide transmission structure, an antenna structure and a connection method, wherein the substrate-integrated waveguide transmission structure includes three metal layers and a row of first signal cutting structures, and the three metal layers are respectively from top to bottom The top metal layer, the middle metal layer and the bottom metal layer; the first signal cut-off structure starts from the top metal layer and ends at the middle metal layer; the middle metal layer and the bottom metal layer on one side of the first signal cut-off structure The first port for connecting the low-profile substrate integrated waveguide is formed between them, and the first port for connecting the high-profile substrate integrated waveguide is formed between the top metal layer and the bottom metal layer on the other side of the first signal cut-off structure. Two ports. The transmission structure proposed by the invention solves the problem of board-level high-profile substrate integrated waveguide device and radio frequency chip interconnection, and has the advantages of low cost, small size, board-level integration and the like.

Description

Substrate integrated waveguide transmission structure, antenna structure and connection method

technical field

The invention relates to the fields of electronics, microwave radio frequency, radar and the like, in particular to a transmission structure, an antenna structure and a connection method between substrate integrated waveguides with different section heights.

Background technique

Substrate integrated waveguide (SIW) is a new type of waveguide structure that can be integrated into a dielectric substrate. This structure arranges multiple metallized through holes at a certain interval in the dielectric substrate to form a smooth side wall of the waveguide. The alternative structure of the metal waveguide forms a quasi-closed waveguide structure with the metal on the upper and lower surfaces, which maintains the characteristics of low insertion loss and high power capacity of the metal waveguide. Substrate-integrated waveguides have been successfully used to design various microwave structures, such as substrate-integrated waveguide antennas, filters, duplexers, and power splitters.

The substrate-integrated waveguide belongs to the height-reducing waveguide (the height is much lower than its width, and the height of the traditional metal waveguide is generally half of the waveguide width). The use of a high-profile dielectric substrate to make the SIW is beneficial to improve its power capacity on the one hand, and on the other hand On the one hand, it is beneficial to improve the impedance bandwidth, gain and other performances of the antenna based on this design.

In actual radio frequency systems, chips often need to be placed on low-profile dielectric substrates. This is because chip pins are generally connected to other parts of the circuit through microstrip lines or coplanar waveguides. The spacing of the substrate is generally small, so the signal lines that need to be connected to it cannot be too wide; for microstrip lines and coplanar waveguides with a characteristic impedance of 50 ohms, the thinner the substrate, the thinner the signal lines will be.

Based on the above facts, in general, it is difficult for antennas or other devices designed based on high-profile substrate integrated waveguides to be directly connected to RF chips through microstrip lines or coplanar waveguides on the same substrate. The width of the waveguide will inevitably have an adverse effect on the performance of antennas and other related devices. Therefore, it is very urgent and meaningful to solve the problem of interconnection between chips and high-profile circuit boards.

Contents of the invention

The problem to be solved by the present invention is to propose a transmission structure to solve the problem of interconnection between board-level high-profile substrate integrated waveguide devices and radio frequency chips, and this solution has the advantages of low cost, small size, and board-level integration.

In order to achieve the above object, the technical solution of the present invention is achieved in that:

A substrate-integrated waveguide transmission structure, characterized in that it includes three metal layers and a row of first signal cut-off structures, and the three metal layers are respectively a top metal layer, a middle metal layer and a bottom metal layer from top to bottom; The first signal cut-off structure starts from the top metal layer and ends at the middle metal layer; between the middle metal layer and the bottom metal layer on one side of the first signal cut-off structure is formed for connecting the low-profile substrate integrated waveguide The first port is formed between the top metal layer and the bottom metal layer on the other side of the first signal cut-off structure, and a second port for connecting the high-profile substrate integrated waveguide is formed.

A low-profile substrate-integrated waveguide transmission line is connected to the first port, and the low-profile substrate-integrated waveguide transmission line includes a bottom metal layer, an intermediate metal layer, a medium between two metal layers, and a Two rows of parallel second signal cut-off structures, the arrangement direction of the second signal cut-off structures is perpendicular to the arrangement direction of the first signal cut-off structures; a high-profile substrate integrated waveguide transmission line is connected to the second port, so The high-profile substrate integrated waveguide transmission line includes a bottom metal layer, a top metal layer, a medium between the two metal layers, and two rows of parallel third signal cut-off structures passing through the two layers of metal. The third signal cut-off structure The arrangement direction is perpendicular to the arrangement direction of the first signal cut-off structure.

The high-profile substrate integrated waveguide transmission line also includes a fourth signal cut-off structure, the fourth signal cut-off structure is symmetrically distributed on both sides of the center line of the two rows of third signal cut-off structures, and the fourth signal cut-off structure starts from the first A signal cut-off structure, and the farther away from the first signal cut-off structure, the farther the distribution of the fourth signal cut-off structure is from the symmetry axis.

The first signal breaking structure is a metallized hole or a metallized groove.

The second signal cut-off structure is a metallized hole or a metallized groove; the third signal cut-off structure is a metallized hole or a metallized groove.

The fourth signal breaking structure is a metallized hole or a metallized groove.

The transmission structure is realized by a multi-layer printed circuit board process. Under the multi-layer printed circuit board process, the entire multi-layer structure from top to bottom is the top metal layer, the first dielectric substrate, the middle metal layer, and the paste sheet, the second layer of dielectric substrate, the underlying metal, and the second signal cut-off structure of the low-profile substrate integrated waveguide and the third signal cut-off structure of the high-profile substrate integrated waveguide are all metallized through-holes that penetrate the entire circuit structure A hole or a slot; the first signal cut-off structure is a blind hole or slot whose top starts from the top metal layer and ends at the middle metal layer.

A substrate-integrated waveguide slot array antenna structure capable of board-level integration directly with a radio frequency chip, characterized in that it includes an antenna input terminal and an antenna radiation terminal; the antenna input port adopts a low-profile substrate-integrated waveguide; the antenna radiation terminal A high-profile substrate-integrated waveguide is adopted, the ends of the high-profile substrate-integrated waveguide are short-circuited and a rectangular groove is opened at the top; any of the transmission methods described above is adopted between the low-profile substrate-integrated waveguide and the high-profile substrate-integrated waveguide structure to connect.

The distance between the centers of adjacent rectangular grooves along the direction of the grooves is half of the waveguide wavelength, and the adjacent rectangular grooves are alternately arranged on both sides of the central line of the integrated waveguide of the high-profile substrate.

A method for connecting a substrate-integrated waveguide slot array antenna structure and a radio frequency chip, characterized in that the low-profile substrate-integrated waveguide adopts a transition structure from a substrate-integrated waveguide to a microstrip transmission line or from a substrate-integrated waveguide to a coplanar waveguide. Fifty ohm microstrip lines or coplanar waveguides are then directly integrated with RF chips on the circuit board.

Compared with prior art, technical effect of the present invention is:

1. Because the radio frequency chip needs to be surface-mounted on a low-profile dielectric substrate to ensure that the width of the signal line that can be directly connected to its pins meets the size limit of the pins, the transmission structure provided by the present invention realizes high and low profile substrates. The transition of chip integrated waveguide can solve the problem of board-level high-profile substrate integrated waveguide device interconnection with radio frequency chips, and this solution has the advantages of low cost, small size, and board-level integration.

2. "The fourth metallized holes symmetrically distributed on both sides of the center line of the third metallized holes in the two rows" can compensate for the discontinuity at the interface, thus effectively improving the integration of low-profile substrate integrated waveguides and high-profile substrates. The influence of the signal discontinuity caused by the sudden change of profile at the chip integrated waveguide interface (that is, the first metallized hole).

Description of drawings

Fig. 1 is a schematic diagram of the transmission structure between substrate integrated waveguides with different cross-sectional heights involved in the present invention;

Fig. 2 is a schematic diagram of the transmission structure hierarchy between substrate integrated waveguides with different cross-sectional heights involved in the present invention;

Fig. 3 is a schematic diagram of the transmission structure between substrate integrated waveguides with different cross-sectional heights manufactured based on the PCB process according to the present invention;

Fig. 4 is a schematic structural diagram of a substrate-integrated waveguide slot array antenna capable of board-level integration directly with a radio frequency chip according to the present invention;

Fig. 5 is an example simulation result of the transmission structure between substrate integrated waveguides with different section heights involved in the present invention.

Fig. 6 is an example |S11| simulation result of a substrate-integrated waveguide slot array antenna structure that can be directly integrated with a radio frequency chip at the board level according to the present invention.

FIG. 7 is a simulation result of an E-plane pattern of an example of a substrate-integrated waveguide slot array antenna structure that can be directly integrated with a radio frequency chip at the board level according to the present invention.

Fig. 8 is a simulation result of an H-plane pattern of an example of a substrate-integrated waveguide slot array antenna structure that can be directly integrated with a radio frequency chip at the board level according to the present invention.

Among them: 1. Low-profile substrate-integrated waveguide transmission line; 2. Transition structure; 3. High-profile substrate-integrated waveguide transmission line; 4. Top metal layer; 5. Middle metal layer; 6. Bottom metal layer; 7-10. Metallized hole; 11. interface; 12. metallized hole; 13. first layer of dielectric substrate; 14. adhesive sheet; 15. second layer of dielectric substrate; 16. slot array antenna; 17. rectangular slot; . Transition structure from substrate integrated waveguide to microstrip transmission line; 19. Fifty ohm microstrip line; 20. Symmetry axis.

Detailed ways

Below in conjunction with accompanying drawing, the present invention is described in further detail:

As shown in accompanying drawings 1 and 2, the substrate-integrated waveguide transition structure 2 of the present invention is the same as connecting two substrate-integrated waveguides with different profiles, including three metal layers and a row of metallized holes 12 (metal The side view structure of the metallized hole 12 is shown in Figure 2), the three metal layers from top to bottom are the top metal layer 4, the middle metal layer 5 and the bottom metal layer 6, and the metallized hole 12 starts from the top metal layer 4 , terminated at the middle metal layer 5 . Two ports are formed on both sides of the metallized hole 12, one port is located between the middle metal layer 5 and the bottom metal layer 6, and is a low-profile substrate-integrated waveguide structure, connected to the low-profile substrate-integrated waveguide transmission line 1; one port Located between the upper metal layer 4 and the bottom metal layer 6 is a high-profile substrate-integrated waveguide structure connected to the high-profile substrate-integrated waveguide transmission line 3 . The low-profile substrate-integrated waveguide transmission line 1 is parallel to the high-profile substrate-integrated waveguide transmission line 3, and the intermediate metal layer 5 exists only on the side of the low-profile substrate-integrated waveguide in the entire circuit board (that is, the low-profile substrate-integrated waveguide transmission line 1 within the area).

Vertical metallized holes 12 (the aperture and hole spacing meet the corresponding requirements of aperture and hole spacing in the traditional substrate integrated waveguide design) are used as the interface 11 of the substrate integrated waveguide with two profile heights. This row of metallized holes 12 is in the section The direction starts from the top metal layer 4 and ends at the middle metal layer 5 (the side view structure of the metallized hole 12 is shown in Figure 2. The center of this row of metallized holes is located in the middle metal layer in the integration of high and low profile substrates. On the interface 11 in the transfer structure area between the waveguides. The transfer structure is located within a certain length of this side of the high-profile substrate integrated waveguide transmission line 3 (this length is related to the operating frequency of the designed transmission structure, and the length is about It is half of the waveguide wavelength, optimized by commercial simulation software, so that both |S11| and |S22| are less than -15dB in the required frequency range), and there are some metallized holes symmetrically distributed along the symmetry axis of the transfer structure 9 (The aperture and hole spacing of the metallized holes 9 meet the corresponding requirements of the aperture and hole spacing in the traditional substrate integrated waveguide design, and the inclination angle is related to the distribution length of the fourth metallized blind holes along the distribution direction of the third metallized holes, this The distribution length is related to the working frequency of the designed transmission structure, the initial value can be set to half the waveguide wavelength, and then optimized by commercial simulation software to achieve the best transmission effect in the required frequency band), these metallized holes 9 starts at the interface 11, and the farther away from the interface 11, the farther the centers of these metallized holes 9 are from the axis of symmetry. In the transition structure 2 between the high and low profile substrate integrated waveguides, there are no holes distributed along the axis of symmetry The area of the metallized blind hole has a shape similar to a triangle.

The low-profile substrate integrated waveguide transmission line 1 is composed of the bottom metal layer 6, the middle metal layer 5, the medium between the two metal layers and two rows of parallel metallized holes 7 passing through the two layers of metal (the metallized holes 7 holes The side view structure is shown in Figure 2); the high-profile substrate integrated waveguide transmission line 3 consists of a bottom metal layer 6, a top metal layer 4, a medium between the two metal layers and two parallel rows of The metallized hole 10 is formed (the side view structure of the metallized hole 10 is shown in FIG. 2 );

The transmission structure can be realized by a multilayer printed circuit board process. Under the multilayer printed circuit board process, the entire multilayer structure is the top metal layer 4, the first dielectric substrate 13, and the middle metal layer 5 from top to bottom. , the adhesive sheet 14, the second dielectric substrate 15, the bottom metal 6, and the metallized holes that constitute the low-profile substrate-integrated waveguide and the high-profile substrate-integrated waveguide are all metallized through-holes 10, that is, the metallized holes penetrate the entire circuit structure. The metallized hole 12 in the transfer structure is a blind hole structure, the top of the blind hole starts from the top metal layer 4 , and the bottom of the blind hole ends at the middle metal layer 5 . The signal flow in the entire transmission structure is shown by the dotted line in Fig. 3 .

All the aforementioned metallized holes (7, 9, 10, 12) forming the integrated waveguide of the substrate can also adopt the structure of metallized grooves.

A substrate-integrated waveguide slot array antenna structure that can be directly integrated with a radio frequency chip at the board level. The input port of the antenna adopts a low-profile substrate-integrated waveguide 1, and the radiation part of the antenna adopts a high-profile substrate-integrated waveguide with a short-circuited top opening. In the form of rectangular slots 17, the distance between the centers of adjacent rectangular slots 17 along the slot direction is half the waveguide wavelength, and the adjacent rectangular slots are alternately arranged on both sides of the center line of the integrated waveguide of the high-profile substrate; the input port The low-profile substrate-integrated waveguide adopts the transmission structure 2 between the substrate-integrated waveguides with different section heights of the present invention to connect with the slot array antenna 16 designed with the high-profile substrate-integrated waveguide; the low-profile substrate-integrated waveguide of the input port adopts the base The transition structure 18 from chip integrated waveguide to microstrip transmission line (or the transition structure from substrate integrated waveguide to coplanar waveguide) transitions to fifty ohm microstrip line 19 (or coplanar waveguide), and then can be directly integrated with the radio frequency chip in the circuit board.

In order to verify the transmission structure between substrate-integrated waveguides with different cross-sectional heights provided by the invention and the performance of a substrate-integrated waveguide slot array antenna structure that can be directly integrated with radio frequency chips at the board level, based on the above structure and PCB technology, respectively An example of a transmission structure working near 77GHz and a substrate-integrated waveguide slot array antenna structure based on this transmission structure is designed. The transmission structure and the substrate-integrated waveguide slot antenna hierarchy are shown in Figure 3, the substrate-integrated waveguide slot antenna The structure is shown in Figure 4, wherein the first layer of dielectric substrate 16 adopts a microwave plate with a dielectric constant of 3.0 and a thickness of 0.254 mm, the adhesive sheet 17 adopts a material with a dielectric constant of 3.54 and a thickness of 0.1 mm, and the second layer of dielectric The substrate 18 is a microwave plate with a dielectric constant of 3.0 and a thickness of 0.127 mm. The case simulation results of the transmission structure between substrate-integrated waveguides with different cross-sectional heights are shown in Figure 5, a related performance simulation of an example of a substrate-integrated waveguide slot array antenna structure that can be directly integrated with a radio frequency chip at the board level The result is shown in accompanying drawing 6-accompanying drawing 8. The simulation results of Figure 5 show that in the range of 75-80GHz, the |S11| and |S22| of the case transmission structure are both less than -15dB, and the insertion loss is less than 1dB; The |S11| of the substrate-integrated waveguide slot antenna is less than -10dB in the range of 76.8-79.5GHz. The results of accompanying drawings 7 and 8 show that the example substrate integrated waveguide slot antenna obtains a normal radiation pattern; the results of related simulation experiments all prove the validity of the proposed structure of the invention.

The above embodiments are only to illustrate the technical ideas of the present invention, and can not limit the protection scope of the present invention with this. All technical ideas proposed in accordance with the present invention, any changes made on the basis of technical solutions, all fall within the protection scope of the present invention. Inside.

Claims (10)

1. A substrate-integrated waveguide transmission structure, characterized in that: it includes three metal layers and a row of first signal cut-off structures, and the three metal layers are respectively a top metal layer, an intermediate metal layer and a bottom metal layer from top to bottom ; The first signal cut-off structure starts from the top metal layer and ends at the middle metal layer; between the middle metal layer and the bottom metal layer on one side of the first signal cut-off structure is formed for connecting the low-profile substrate integration The first port of the waveguide is formed between the top metal layer and the bottom metal layer on the other side of the first signal cut-off structure, and a second port for connecting the high-profile substrate integrated waveguide is formed. 2. The substrate-integrated waveguide transmission structure according to claim 1, characterized in that: a low-profile substrate-integrated waveguide transmission line is connected to the first port, and the low-profile substrate-integrated waveguide transmission line includes a bottom metal layer, The middle metal layer, the medium between the two metal layers, and two rows of parallel second signal cut-off structures passing through the two layers of metal, the arrangement direction of the second signal cut-off structures is the same as that of the first signal cut-off structures The direction is vertical; a high-profile substrate-integrated waveguide transmission line is connected to the second port, and the high-profile substrate-integrated waveguide transmission line includes a bottom metal layer, a top metal layer, a medium between two metal layers, and a medium passing through the two There are two parallel rows of third signal cut-off structures on the layer metal, and the arrangement direction of the third signal cut-off structures is perpendicular to the arrangement direction of the first signal cut-off structures. 3. The substrate-integrated waveguide transmission structure according to claim 2, characterized in that: the high-profile substrate-integrated waveguide transmission line further includes a fourth signal cut-off structure, and the fourth signal cut-off structure is symmetrically distributed in two rows On both sides of the center line of the three signal cut-off structures, the fourth signal cut-off structure starts from the first signal cut-off structure, and the farther away from the first signal cut-off structure, the farther the distribution of the fourth signal cut-off structure is from the symmetry axis. 4. The substrate-integrated waveguide transmission structure according to claim 1, wherein the first signal cutting structure is a metallized hole or a metallized groove. 5. The substrate-integrated waveguide transmission structure according to claim 2, characterized in that: the second signal cut-off structure is a metallized hole or a metallized groove; the third signal cut-off structure is a metallized hole or a metallized groove groove. 6. The substrate-integrated waveguide transmission structure according to claim 3, wherein the fourth signal cutting structure is a metallized hole or a metallized groove. 7. The substrate-integrated waveguide transmission structure according to any one of claims 1 to 6, characterized in that: the transmission structure is realized by a multi-layer printed circuit board process, and under the multi-layer printed circuit board process, the entire multi-layer The layer structure from top to bottom is the top metal layer, the first layer of dielectric substrate, the middle metal layer, the paste sheet, the second layer of dielectric substrate, the bottom metal, and constitute the second signal cut-off structure of the low-profile substrate integrated waveguide The third signal cut-off structure of the high-profile substrate integrated waveguide is a metallized through hole or slot that penetrates the entire circuit structure; the first signal cut-off structure starts from the top metal layer at the top and ends at the middle metal layer at the bottom Blind holes or slots. 8. A substrate-integrated waveguide slot array antenna structure capable of board-level integration directly with a radio frequency chip, characterized in that it includes an antenna input terminal and an antenna radiation terminal; the antenna input port adopts a low-profile substrate-integrated waveguide; the antenna The radiating end adopts a high-profile substrate-integrated waveguide, the end of the high-profile substrate-integrated waveguide is short-circuited and a rectangular groove is opened at the top; claims 1-7 are adopted between the low-profile substrate-integrated waveguide and the high-profile substrate-integrated waveguide. Any of the transport structures described above are connected. 9. The substrate-integrated waveguide slot array antenna structure according to claim 8, characterized in that the distance between the centers of adjacent rectangular slots along the slot direction is half a waveguide wavelength, and the adjacent rectangular slots are staggered at a height Profile the substrate on both sides of the centerline of the integrated waveguide. 10. A method for connecting a substrate integrated waveguide slot array antenna structure and a radio frequency chip as claimed in claim 8 or 9, wherein the low profile substrate integrated waveguide adopts substrate integrated waveguide to microstrip transmission line or substrate integrated The transition structure from the waveguide to the coplanar waveguide transitions to a fifty-ohm microstrip line or a coplanar waveguide, and then directly integrates with the radio frequency chip on the circuit board.