Transition structure from radio frequency chip to substrate integrated waveguide and its application method

Abstract

The present invention provides a transition structure from a radio frequency chip to a substrate integrated waveguide, the transition structure comprising: a substrate integrated waveguide and a radio frequency chip. The substrate integrated waveguide comprises a substrate, a first through hole, a second through hole, and a coupling structure, wherein the second through hole is the grounding end of the substrate integrated waveguide; the coupling structure is located between two rows of first through holes; and the radio frequency chip is located above the coupling structure. During the application of the transition structure, the radio frequency signal of the radio frequency chip enters the substrate integrated waveguide, the coupling structure changes the surface current to excite multi-mode resonance, and couples the radio frequency signal to the substrate integrated waveguide in the form of an electromagnetic wave. Since the second through hole is grounded, the electromagnetic wave is impedance matched through the second through hole during transmission along the arrangement direction of the first through holes. The present invention provides a transition structure with broadband and low loss characteristics through the coordination between the coupling structure, the first through hole, and the second through hole, and does not provide a microstrip line, thereby avoiding radiation loss.

Description

Technical Field

[0001] The present invention relates to the field of millimeter wave electronic technology, and in particular to a transition structure from a radio frequency chip to a substrate integrated waveguide and an application method thereof. Background Art

[0002] Substrate Integrated Waveguide (SIW) is a novel transmission line structure that combines traditional rectangular waveguides with microstrip technology. It has a wide range of applications in microwave and millimeter wave communications, antenna design, and radio frequency integrated circuits.

[0003] In the existing technology, although the combination of substrate integrated waveguide and microstrip line technology can transmit radio frequency signals to the antenna end, microstrip lines are prone to radiation loss during the application of millimeter wave communication, resulting in reduced signal transmission efficiency. Summary of the Invention

[0004] In view of this, the present invention provides a transition structure from a radio frequency chip to a substrate integrated waveguide, which has the characteristics of broadband and low loss, avoids radiation loss, and improves signal transmission efficiency.

[0005] A transition structure from a radio frequency chip to a substrate integrated waveguide, comprising:

[0006] a substrate integrated waveguide, and a radio frequency chip connected to the substrate integrated waveguide via at least one welding block;

[0007] The substrate integrated waveguide comprises a substrate, two rows of first through holes arranged in parallel and equidistantly, a second through hole perpendicular to the two rows of the first through holes, and a coupling structure, wherein the second through hole serves as a ground terminal of the substrate integrated waveguide;

[0008] Wherein, the first through hole and the second through hole pass through the substrate;

[0009] The coupling structure is located between two rows of the first through holes;

[0010] The radio frequency chip is located above the coupling structure.

[0011] The above-mentioned transition structure from the RF chip to the substrate integrated waveguide, optionally, the substrate is a RF PCB board.

[0012] The above-mentioned transition structure from the RF chip to the substrate integrated waveguide, optionally, the RF chip is a chip packaged in a Fanout manner.

[0013] In the above-mentioned transition structure from the radio frequency chip to the substrate integrated waveguide, optionally, the welding block is a BGA solder ball, and the BGA solder ball is a cylinder.

[0014] In the above-mentioned transition structure from the RF chip to the substrate integrated waveguide, optionally, the BGA solder balls include first-type BGA solder balls and second-type BGA solder balls;

[0015] The radio frequency chip is connected to the substrate of the substrate integrated waveguide through the first type BGA solder balls;

[0016] The radio frequency chip is connected to the coupling structure of the substrate integrated waveguide through the second type BGA solder balls.

[0017] The above-mentioned transition structure from the RF chip to the substrate integrated waveguide, optionally, the coupling structure includes a coupling patch and a coupling gap, and the coupling patch is completely fitted with the bottom of the second type BGA solder ball.

[0018] In the above-mentioned transition structure from the RF chip to the substrate integrated waveguide, optionally, the inner diameter of the coupling slot is consistent with the diameter of the coupling patch, and the outer diameter of the coupling slot is smaller than the shortest distance between the two rows of the first through holes.

[0019] An application method based on the above-mentioned radio frequency chip to substrate integrated waveguide transition structure comprises:

[0020] The radio frequency chip outputs a radio frequency signal to the coupling structure of the substrate integrated waveguide through the welding block, and the radio frequency signal forms a current on the surface when passing through the coupling structure;

[0021] The coupling structure changes the current-excited multi-mode resonance and transmits the radio frequency signal in the form of electromagnetic waves along the arrangement direction of the first through holes of the substrate integrated waveguide;

[0022] The second through hole of the substrate integrated waveguide intercepts the electromagnetic wave to perform impedance matching.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] The present invention provides a transition structure from a radio frequency chip to a substrate integrated waveguide, comprising: a substrate integrated waveguide and a radio frequency chip. The substrate integrated waveguide comprises a substrate, two rows of parallel and equidistant first through holes, a second through hole perpendicular to the two rows of first through holes, and a coupling structure, wherein the second through hole serves as the ground terminal of the substrate integrated waveguide. The first and second through holes extend through the substrate; the coupling structure is located between the two rows of first through holes; and the radio frequency chip is located above the coupling structure. During application of the transition structure, the radio frequency signal from the radio frequency chip enters the substrate integrated waveguide through the coupling structure. When the radio frequency signal passes through the coupling structure, a current is generated on the surface. The coupling structure changes the surface current to excite multimode resonance, thereby coupling the radio frequency signal to the substrate integrated waveguide in the form of an electromagnetic wave. Since the second through hole in the substrate integrated waveguide is grounded, serving as the ground terminal of the substrate integrated waveguide, the electromagnetic wave is short-circuited at one end through the second through hole during transmission along the arrangement direction of the first through holes for impedance matching. The present invention enables the transition structure of the present invention to have broadband and low-loss characteristics through the coordination between the coupling structure, the first through hole and the second through hole, and does not require the provision of a microstrip line, thereby avoiding radiation loss and improving signal transmission efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0026] Figure 1 A three-dimensional view of a transition structure from a radio frequency chip to a substrate integrated waveguide provided in an embodiment of the present invention;

[0027] Figure 2 (a) and (b) are respectively a three-dimensional view and a top view of the substrate integrated waveguide structure provided by an embodiment of the present invention;

[0028] Figure 3 A three-dimensional view of a radio frequency chip provided in an embodiment of the present invention;

[0029] Figure 4 A transmission loss diagram of a transition structure from a radio frequency chip to a substrate integrated waveguide provided in an embodiment of the present invention;

[0030] Figure 5 A schematic diagram of the standing wave ratio of the transition structure from the RF chip to the substrate integrated waveguide provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] In this application, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. The terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or apparatus comprising the element.

[0033] The present invention can be used in a variety of general-purpose or special-purpose computing device environments or configurations, such as personal computers, server computers, handheld or portable devices, tablet devices, multi-processor devices, and distributed computing environments including any of the above.

[0034] The embodiment of the present invention provides a transition structure from a radio frequency chip to a substrate integrated waveguide, referring to Figure 1 The transition structure includes an RF chip A and a substrate integrated waveguide B. The RF chip A is used to transmit RF signals. After the RF signal is transmitted to the substrate integrated waveguide B, it is transmitted in the substrate integrated waveguide B in the form of electromagnetic waves. The electromagnetic waves are transmitted along the arrangement direction of the two rows of first through holes. The electromagnetic waves are cut off at a row of second through holes perpendicular to the two rows of first through holes. The first through holes and the second through holes pass through the substrate. Both the first through holes and the second through holes are grounded through holes. The second through hole is the grounding end of the substrate integrated waveguide. Since the coupling structure of the substrate integrated waveguide B is located between the two rows of first through holes, the RF signal emitted by the RF chip A located above the coupling structure is directly transmitted to the coupling structure. After receiving the RF signal, the coupling structure generates excitation to form an electromagnetic wave that is transmitted in the arrangement direction of the first through holes.

[0035] In an embodiment of the present invention, the coupling structure consists of a coupling patch and a coupling slot. The coupling slot does not penetrate the substrate, and the coupling patch is a metal patch. The RF signal is transmitted via the RF chip to the coupling patch of substrate-integrated waveguide B. The coupling slot modifies the surface current, exciting multimode resonance and coupling the electromagnetic wave into substrate-integrated waveguide B.

[0036] In an embodiment of the present invention, during the process of coupling the electromagnetic wave to the substrate integrated waveguide B through the coupling slot, the electromagnetic wave transmitted along the first through hole is cut off when it reaches the location of the second through hole. The second through hole is the short-circuit end in the substrate integrated waveguide B, and the short-circuit end is used for impedance matching.

[0037] In the embodiment of the present invention, reference Figure 2 , Figure 2 (a) is a three-dimensional view of substrate-integrated waveguide B. Figure 2 (b) is a top view of the substrate integrated waveguide B. The substrate in the substrate integrated waveguide B is an RF PCB board, and its material can be Rogers' RO3003 board. The coupling structure on the RF PCB board includes a coupling patch B1 and a coupling slot B2. At the same time, two rows of parallel first through holes are opened. At one end of the two rows of through holes away from the edge of the substrate, a row of second through holes B3 perpendicular to the two rows of first through holes is opened. Between the two rows of first through holes and on the side close to the second through hole B3, a coupling structure consisting of a coupling slot B2 and a coupling patch B1 is opened. Therefore, the RF PCB board, the first through hole, the second through hole B3, the coupling patch B1 and the coupling slot B2 in the present invention constitute the substrate integrated waveguide B. Among them, the aperture of the second through hole B3 can be consistent with the aperture of the first through hole, and the first through hole and the second through hole B3 are both grounding through holes; the inner diameter of the coupling gap B2 is consistent with the diameter of the coupling patch B1, and the outer diameter of the coupling gap B2 is smaller than the shortest distance between the two rows of first through holes. The width of the coupling gap B2 in the coupling structure affects the coupling efficiency of the electromagnetic wave; the coupling patch B1 is a circular metal patch attached to the surface of the substrate.

[0038] In an embodiment of the present invention, the packaging method of the RF chip A connected to the substrate integrated waveguide B is a Fanout packaging method, that is, the RF chip is a Fanout packaged RF chip, such as Figure 3 As shown, the Fanout packaged RF chip includes a package housing and a chip body. The chip body is encapsulated by the package housing and soldered to the substrate integrated waveguide via solder bumps A1 and A1-1. The solder bumps are cylindrical BGA solder balls (e.g., a cylinder with a diameter of 2mm and a height of 1.58mm). The height and diameter of the cylindrical BGA solder balls can be adjusted based on the RF chip packaging requirements. The BGA solder balls are taller than the RF chip package housing.

[0039] In each BGA solder ball of the Fanout packaged RF chip, in addition to soldering the Fanout packaged RF chip to the substrate integrated waveguide, each BGA solder ball can also realize the functions of conducting electricity and transmitting signals. Figure 3 A1 in the figure is a first-class BGA solder ball, and A1-1 is a second-class BGA solder ball. The first-class BGA solder ball connects the Fanout packaged RF chip to the substrate and is used to supply power and ground the substrate-integrated waveguide B. The second-class BGA solder ball connects the Fanout packaged RF chip to the coupling patch of the coupling structure and is used to transmit the RF signal from the Fanout packaged RF chip to the substrate-integrated waveguide B. The diameter of the coupling patch B1 is consistent with that of the BGA solder ball, and the coupling patch B1 is completely aligned with the bottom of the second-class BGA solder ball.

[0040] The transition structure achieves broadband, low-loss characteristics through the coordinated use of coupling patch B1, coupling slot B2, and second through-hole B3. It should be noted that the dimensions of coupling patch B1, coupling slot B2, and the short-circuit matching end of substrate-integrated waveguide B vary with the operating frequency and type of the Fanout packaged RF chip.

[0041] When the Fanout packaged RF chip is soldered to the substrate integrated waveguide B via BGA solder balls, the Fanout packaged RF chip can be completely adhered to the substrate integrated waveguide B, or a gap can be formed between the Fanout packaged RF chip and the substrate integrated waveguide B. In the transition structure of the present invention, the size of the Fanout packaged RF chip, the position of the coupling structure on the substrate integrated waveguide B, the size of the substrate, and the shortest distance between the two rows of first through-holes are related to the frequency of the signal transmitted by the Fanout packaged RF chip.

[0042] In an embodiment of the present invention, an application method based on the above-mentioned transition structure from the RF chip to the substrate integrated waveguide is as follows:

[0043] The RF chip outputs an RF signal to the coupling structure of the substrate integrated waveguide through the welding block. When the RF signal passes through the coupling structure, a current is formed on the surface; the coupling structure changes the current to excite multi-mode resonance, and transmits the RF signal in the form of an electromagnetic wave along the arrangement direction of the first through hole of the substrate integrated waveguide; the second through hole of the substrate integrated waveguide intercepts the electromagnetic wave for impedance matching.

[0044] During the application of this transition structure, the RF signal of the RF chip enters the substrate integrated waveguide through the coupling structure. When the RF signal passes through the coupling structure, a current is formed on the surface. The coupling structure changes the surface current to excite multi-mode resonance, and then couples the RF signal to the substrate integrated waveguide in the form of an electromagnetic wave. Since the second through-hole in the substrate integrated waveguide is grounded and serves as the grounding end of the substrate integrated waveguide, the electromagnetic wave is transmitted along the arrangement direction of the first through-hole. The second through-hole is used as a short circuit at one end for impedance matching. The present invention provides the transition structure of the present invention with broadband and low-loss characteristics through the coordination between the coupling structure, the first through-hole and the second through-hole. The transition structure of the present invention can perform signal transmission and impedance matching in a broadband and low-loss situation without the need to set up a microstrip line. What is different from the semi-open electromagnetic characteristics of the microstrip line is that the electromagnetic shielding characteristics based on the substrate integrated waveguide can effectively improve the signal-to-noise ratio of the Fanout packaged RF chip.

[0045] Figure 4 and Figure 5 The simulation and test results of the transition structure of the present invention based on the above embodiment are shown in FIG. Figure 4 This is a transmission loss diagram of the transition results between simulation and test results. The horizontal axis represents frequency and the vertical axis represents loss. Figure 5 The figure shows the transition between the simulation and test results. The horizontal axis represents the frequency and the vertical axis represents the standing wave ratio. Figure 4 and Figure 5 It can be seen that the transmission loss of the transition structure of the present invention is less than 1.5dB at 80GHz~100GHz (e.g. Figure 4 The frequency range marked by points m1 and m2 shown in the figure has a transmission loss of less than 1.5dB), and the standing wave ratio is less than 2 in the range of 80GHz to 100GHz.

[0046] Each embodiment in this specification is described in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple. For relevant parts, refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without expending creative work.

[0047] Those skilled in the art may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein may be implemented by electronic hardware, computer software, or a combination of both.

[0048] To clearly illustrate the interchangeability of hardware and software, the above descriptions have generally described the components and steps of each example by function. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Professionals may use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the present invention.

[0049] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A transition structure from a radio frequency chip to a substrate integrated waveguide, characterized in that: include: a substrate integrated waveguide, and a radio frequency chip connected to the substrate integrated waveguide via at least one welding block; The substrate integrated waveguide comprises a substrate, two rows of first through holes arranged in parallel and equidistantly, a second through hole perpendicular to the two rows of the first through holes, and a coupling structure, wherein the second through hole serves as a ground terminal of the substrate integrated waveguide; Wherein, the first through hole and the second through hole pass through the substrate; The coupling structure is located between two rows of the first through holes; the coupling structure includes a coupling patch and a coupling gap; the coupling patch is a circular metal patch attached to the surface of the substrate; the inner diameter of the coupling gap is consistent with the diameter of the coupling patch; The radio frequency chip is located above the coupling structure; The welding block is a BGA solder ball, and the BGA solder ball is a cylinder; the BGA solder ball includes a first type BGA solder ball and a second type BGA solder ball; The radio frequency chip is connected to the substrate of the substrate integrated waveguide through the first type BGA solder balls; The radio frequency chip is connected to the coupling structure of the substrate integrated waveguide through the second type BGA solder balls; The coupling patch is completely fitted with the bottom of the second type BGA solder ball.

2. The transition structure from radio frequency chip to substrate integrated waveguide according to claim 1, characterized in that: The substrate is a radio frequency PCB board.

3. The transition structure from radio frequency chip to substrate integrated waveguide according to claim 1, characterized in that: The radio frequency chip is a chip in a Fanout packaging manner.

4. The transition structure from radio frequency chip to substrate integrated waveguide according to claim 3, characterized in that: An outer diameter of the coupling gap is smaller than the shortest distance between two rows of the first through holes.

5. An application method of the transition structure from radio frequency chip to substrate integrated waveguide according to any one of claims 1 to 4, characterized in that: include: The radio frequency chip outputs a radio frequency signal to the coupling structure of the substrate integrated waveguide through the welding block, and the radio frequency signal forms a current on the surface when passing through the coupling structure; The coupling structure changes the current-excited multi-mode resonance and transmits the radio frequency signal in the form of electromagnetic waves along the arrangement direction of the first through holes of the substrate integrated waveguide; The second through hole of the substrate integrated waveguide intercepts the electromagnetic wave to perform impedance matching.

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