CN219893511U - Radio frequency connection structure and radio frequency front end module - Google Patents

Abstract

The utility model discloses a radio frequency connection structure, which comprises a substrate and a radio frequency transmission line, wherein the substrate comprises a signal transmission layer and at least three layers of ground layers, the signal transmission layer and the at least three layers of ground layers are arranged from top to bottom, the radio frequency transmission line is arranged on the signal transmission layer, the radio frequency transmission line comprises at least three parts of transmission line segments connected in series between a first connection port and a second connection port, the first connection port is configured to be connected with a test conversion interface, the second connection port is configured to be connected with a bonding pad interface on a chip, the line width of each part of transmission line segments in the horizontal direction is different, the reference stratum of each part of transmission line segments is one of the at least three layers of ground layers, and the reference stratum of each part of transmission line segments is different; thereby improving the problem of discontinuous impedance of the radio frequency connection structure and further optimizing the return loss of the radio frequency connection structure.

Description

Radio frequency connection structure and radio frequency front end module

Technical Field

The present utility model relates to the field of radio frequency technologies, and in particular, to a radio frequency connection structure and a radio frequency front end module.

Background

With the gradual application of WiFi 6 and 5G technologies, the frequency of Radio Frequency (RF) is higher and higher, and the radio frequency connection structure for connecting the radio frequency chip and the connector test probe row is extended to a frequency band above 5 GHz. The radio frequency connection structure is generally formed by connecting the test conversion interface with a radio frequency transmission line. When the existing radio frequency connection structure transmits radio frequency signals output by the radio frequency chip, the problem of unavoidable impedance discontinuity exists, the problem of impedance discontinuity can obstruct the transmission of the radio frequency signals, and the return loss of the radio frequency port is deteriorated, so that the system test index is affected. Therefore, avoiding impedance discontinuity in the rf connection structure, improving transmission performance, is one of the problems to be solved urgently.

Disclosure of Invention

The embodiment of the utility model provides a radio frequency connection structure and a radio frequency front end module, which are used for solving the problem of discontinuous impedance in the radio frequency connection structure.

The utility model provides a radio frequency connection structure, includes base plate and radio frequency transmission line, the base plate includes signal transmission layer and at least three-layer ground plane, signal transmission layer with at least three-layer ground plane top-down sets up, the radio frequency transmission line sets up on the signal transmission layer, the radio frequency transmission line includes the at least three partial transmission line sections of series connection between first connection port and second connection port, first connection port is configured to be connected with test conversion interface, second connection port is configured to be connected with the pad interface on the chip, and the linewidth of each partial transmission line section is different in the horizontal direction, and the reference stratum of each partial transmission line section is one of them layer ground plane in the at least three-layer ground plane, and the reference stratum of each partial transmission line section is different.

Further, the line width of the transmission line segment connected to the first connection port in the horizontal direction sequentially increases to the line width of the transmission line segment connected to the second connection port in the horizontal direction.

Further, the at least three-part transmission line section comprises a first part transmission line section, a second part transmission line section and a third part transmission line section which are connected in series, wherein the first end of the first part transmission line section is connected with the first connecting port, the second end of the first part transmission line section is connected with the first end of the second part transmission line section through a first connecting part, the second end of the second part transmission line section is connected with the first end of the third part transmission line section through a second connecting part, and the second end of the third part transmission line section is connected with the second connecting port.

Further, the line width of the first part of transmission line segment in the horizontal direction is larger than the line width of the second part of transmission line segment in the horizontal direction, and the line width of the second part of transmission line segment in the horizontal direction is larger than the line width of the third part of transmission line segment in the horizontal direction.

Further, the at least three layers of ground layers include a first ground layer, a second ground layer and a third ground layer, which are disposed from top to bottom, the third ground layer is a reference layer of the first portion of the transmission line section, the second ground layer is a reference layer of the second portion of the transmission line section, and the first ground layer is a reference layer of the third portion of the transmission line section.

Further, the line width of the third part of transmission line segment in the horizontal direction is smaller than or equal to 0.2mm, and the line width of the first part of transmission line segment in the horizontal direction is larger than or equal to 0.5mm.

Further, when the radio frequency connection structure works at 4GHz-8GHz, the impedance of the radio frequency connection structure is between [48 ohms-50 ohms ].

Further, the outer contour of the first connecting portion is an isosceles trapezoid, the isosceles trapezoid comprises a first virtual parallel side and a second virtual parallel side which are parallel to each other, the length of the first virtual parallel side is identical to the line width of the first part of transmission line segment in the horizontal direction, and the length of the second virtual parallel side is identical to the line width of the second part of transmission line segment in the horizontal direction;

the outline of the second connecting part is an isosceles trapezoid, the isosceles trapezoid comprises a third virtual parallel side and a fourth virtual parallel side which are parallel to each other, the length of the third virtual parallel side is identical to the line width of the second part transmission line section in the horizontal direction, and the length of the fourth virtual parallel side is identical to the line width of the third part transmission line section in the horizontal direction.

Further, the substrate is an evaluation board.

The radio frequency front end module is characterized by comprising the radio frequency connecting structure.

The radio frequency connection structure comprises a substrate and a radio frequency transmission line, wherein the substrate comprises a signal transmission layer and at least three layers of ground layers, the signal transmission layer and the at least three layers of ground layers are arranged from top to bottom, the radio frequency transmission line is arranged on the signal transmission layer, the radio frequency transmission line comprises at least three parts of transmission line segments connected in series between a first connection port and a second connection port, the first connection port is configured to be connected with a test conversion interface, the second connection port is configured to be connected with a bonding pad interface on a chip, the line width of each part of transmission line segments in the horizontal direction is different, the reference stratum of each part of transmission line segments is one of the at least three layers of ground layers, and the reference stratum of each part of transmission line segments is different; therefore, the first connection port and the second connection port of the radio frequency transmission line can be respectively matched with the test conversion interface and the bonding pad interface on the chip, the problem of discontinuous impedance of the radio frequency connection structure can be solved, and the return loss of the radio frequency connection structure is optimized.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the description of the embodiments of the present utility model will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a cross-sectional view of an RF connection structure in accordance with one embodiment of the present utility model;

fig. 2 is a simulation diagram of a radio frequency connection structure in the related art;

FIG. 3 is a simulation diagram of a radio frequency connection structure in accordance with the present utility model;

FIG. 4 is another simulation diagram of a radio frequency connection structure in the related art;

FIG. 5 is another simulation of the RF connection structure of the present utility model;

fig. 6 is another simulation diagram of a radio frequency connection structure in the related art;

FIG. 7 is another simulation of the RF connection structure of the present utility model;

in the figure: 100. a substrate; 111. a first partial transmission line segment; 112. a second partial transmission line segment; 113. the third portion of the transmission line segment.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be understood that the present utility model may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the utility model to those skilled in the art. In the drawings, the dimensions and relative dimensions of layers and regions may be exaggerated for the same elements throughout for clarity.

It will be understood that when an element or layer is referred to as being "on" …, "" adjacent to "…," "connected to" or "coupled to" another element or layer, it can be directly on, adjacent to, connected to or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on" …, "" directly adjacent to "…," "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present utility model.

Spatially relative terms, such as "under …," "under …," "below," "under …," "above …," "above," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements or features described as "under" or "beneath" other elements would then be oriented "on" the other elements or features. Thus, the exemplary terms "under …" and "under …" may include both an upper and a lower orientation. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.

In the following description, for the purpose of providing a thorough understanding of the present utility model, detailed structures and steps are presented in order to illustrate the technical solution presented by the present utility model. Preferred embodiments of the present utility model are described in detail below, however, the present utility model may have other embodiments in addition to these detailed descriptions.

The embodiment provides a radio frequency connection structure, as shown in fig. 1 and 3, including a substrate 100 and a radio frequency transmission line, where the substrate 100 includes a signal transmission layer and at least three layers of ground layers, and the signal transmission layer and the at least three layers of ground layers are disposed from top to bottom, that is, the at least three layers of ground layers are metal layers disposed below the signal transmission layer. The radio frequency transmission line is disposed on the signal transmission layer, and includes at least three partial transmission line segments connected in series between a first connection port configured to interface with a test conversion interface and a second connection port configured to interface with a pad on a chip (e.g., a first partial transmission line segment 111, a first partial transmission line segment 112, and a third partial transmission line segment 113 shown in fig. 1). The line width of each part of the transmission line segments in the horizontal direction is different, the reference stratum of each part of the transmission line segments is one of the at least three layers of the ground layers, and the reference stratum of each part of the transmission line segments is different.

The horizontal direction is the direction perpendicular to the radio frequency transmission line in the same space dimension. For example: assuming that one end of the radio frequency transmission line is used as an origin to establish a two-dimensional coordinate system, the X-axis direction is the direction of the radio frequency transmission line, and the Y-axis direction is the horizontal direction in the embodiment.

In one embodiment, the substrate 100 may be an evaluation board/EVB board (evaluation board) or a printed circuit board (Printed circuit board).

In one embodiment, the substrate 100 includes a plurality of metal layers. The top metal layer of the metal layers is a signal transmission layer, and the rest metal layers of the metal layers are all ground layers. The radio frequency transmission line is arranged on the signal transmission layer at the topmost layer. Alternatively, the number of the radio frequency transmission lines disposed on the signal transmission layer may be one or more.

In one embodiment, the first connection port of the RF transmission line is configured to connect with the test transition interface 200. The test conversion interface 200 is an interface where an SMA connector is connected to a radio frequency connection structure. The second connection port of the radio frequency transmission line is configured to interface with a pad on the chip. The interface of the chip is led out and connected to the test conversion interface through the radio frequency transmission line, and can be used for detecting the functions and performances (such as loss, gain, power and the like) of the chip or checking whether the chip can work normally in various severe environments. The chip may be a chip integrated with a power amplifying circuit, a low noise amplifying circuit, a switching circuit, or other radio frequency circuits.

As an example, since the first connection port of the radio frequency transmission line is configured to connect with the test conversion interface, the second connection port is configured to connect with a pad interface on the chip, and the area of the pad interface on the chip is typically much smaller than the area of the test conversion interface. Therefore, in this embodiment, in order to make the first connection port and the second connection port of the radio frequency transmission line respectively fit with the test conversion interface and the pad interface on the chip, the problem that impedance is discontinuous due to an excessively large line width difference between two adjacent transmission line segments in the radio frequency transmission line in the horizontal direction is avoided, or the problem that the impedance adjustment range is limited due to an excessively small adjustable factor of the radio frequency transmission line, so that good matching cannot be achieved is avoided. According to the embodiment, the radio frequency transmission line is divided into at least three transmission line segments connected in series, and the line width of each transmission line segment is different in the horizontal direction, so that the first connection port and the second connection port of the radio frequency transmission line can be respectively matched with the test conversion interface and the bonding pad interface on the chip, the problem of discontinuous impedance of the radio frequency connection structure can be solved, and the return loss of the radio frequency connection structure is optimized.

Alternatively, two adjacent transmission line segments in this embodiment may be directly connected, or may be connected by a connection portion. In this embodiment, the line width of each part of the transmission line section in the horizontal direction is only required to be ensured to be different, and the line width of each part of the transmission line section in the horizontal direction is not limited. Preferably, the line width of the transmission line segment connected with the test conversion interface in the horizontal direction is the largest, and the line width of the transmission line segment connected with the bonding pad interface on the chip in the horizontal direction is the smallest.

Referring to fig. 2 and 3 below, fig. 2 is a diagram showing the simulation result of the impedance when the radio frequency transmission line includes two transmission line segments connected in series in the related art, and fig. 3 is a diagram showing the simulation result of the impedance when the radio frequency transmission line includes at least three transmission line segments connected in series in the present embodiment. As can be seen from fig. 2 and fig. 3, compared with the impedance of the radio frequency connection structure including only two transmission line segments connected in series in the whole operating frequency band in the related art, the impedance of the radio frequency connection structure including at least three transmission line segments connected in series in the whole operating frequency band is closer to 50Ω, and therefore, in this embodiment, by dividing the radio frequency transmission line into at least three transmission line segments connected in series, the line width of each transmission line segment in the horizontal direction is different, so that the problem of discontinuous impedance of the radio frequency connection structure can be improved.

Referring to fig. 4 and 5 below, fig. 4 is a graph of return loss simulation results when the radio frequency transmission line includes two transmission line segments connected in series in the related art, and fig. 5 is a graph of return loss simulation results when the radio frequency transmission line includes at least three transmission line segments connected in series in the present embodiment. As can be seen from fig. 4 and fig. 5, compared with the return loss of the radio frequency connection structure including only two transmission line segments connected in series in the whole working frequency band in the related art, the return loss of the radio frequency connection structure including at least three transmission line segments connected in series in the whole working frequency band is better, especially the effect is particularly obvious when the radio frequency connection structure is in a high frequency band, and therefore, in the present embodiment, the return loss of the radio frequency connection structure can be improved by dividing the radio frequency transmission line into at least three transmission line segments connected in series, and the line width of each transmission line segment is different in the horizontal direction.

In this embodiment, the radio frequency connection structure includes a substrate and a radio frequency transmission line, where the substrate includes a signal transmission layer and at least three layers of ground layers, the signal transmission layer and the at least three layers of ground layers are disposed from top to bottom, the radio frequency transmission line is disposed on the signal transmission layer, the radio frequency transmission line includes at least three parts of transmission line segments connected in series between a first connection port and a second connection port, the first connection port is configured to be connected with a test conversion interface, the second connection port is configured to be connected with a pad interface on a chip, a line width of each part of transmission line segments in a horizontal direction is different, a reference layer of each part of transmission line segments is one of the at least three layers of ground layers, and a reference layer of each part of transmission line segments is different; therefore, the first connection port and the second connection port of the radio frequency transmission line can be respectively matched with the test conversion interface and the bonding pad interface on the chip, the problem of discontinuous impedance of the radio frequency connection structure can be solved, and the return loss of the radio frequency connection structure is optimized.

In a specific embodiment, preferably, the line width of the transmission line segment connected to the first connection port in the horizontal direction sequentially increases to the line width of the transmission line segment connected to the second connection port in the horizontal direction.

As an example, since the first connection port is configured to connect with a test conversion interface, the second connection port is configured to interface with a pad on a chip. Therefore, in order to make the first connection port and the second connection port fit with the test conversion interface and the pad interface on the chip, respectively, the area of the first connection port should be larger than that of the second connection port. Further, in order to adapt the portion of the transmission line segment directly connected to the first connection port and the portion of the transmission line segment directly connected to the second connection port, the line width of the transmission line segment connected to the first connection port in the horizontal direction should be larger than the line width of the transmission line segment connected to the second connection port in the horizontal direction. In order to further avoid that the width difference between two adjacent transmission line segments in the horizontal direction is not too large, the width of the transmission line segment connected with the first connection port in the horizontal direction is sequentially increased to the width of the transmission line segment connected with the second connection port in the horizontal direction, so that the problem of discontinuous impedance of the radio frequency connection structure can be further improved, and the return loss of the radio frequency connection structure is further optimized.

In a specific embodiment, the at least three transmission line segments include a first transmission line segment, a second transmission line segment and a third transmission line segment connected in series, where a first end of the first transmission line segment is connected to the first connection port, a second end of the first transmission line segment is connected to a first end of the second transmission line segment through a first connection portion, a second end of the second transmission line segment is connected to a first end of the third transmission line segment through a second connection portion, and a second end of the third transmission line segment is connected to the second connection port.

As an example, the line widths of the different partial transmission line segments in the horizontal direction are different, and the reference strata of each partial transmission line segment are different. Since the metal layers included in the substrate are limited and cannot include an infinite number of metal layers, the number of the included partial transmission line segments of the radio frequency transmission line is limited. In the practical application process, the number of the transmission line segments of the radio frequency transmission line can be determined according to the number of the practical metal layers of the substrate and the difference between the area of the bonding pad interface and the area of the test conversion interface on the chip.

Specifically, referring to fig. 1, the radio frequency transmission line in this embodiment is described by taking the example that the radio frequency transmission line includes three transmission line segments. The first end of the first part transmission line section is connected with the first connecting port, the second end of the first part transmission line section is connected with the first end of the second part transmission line section through a first connecting part, the second end of the second part transmission line section is connected with the first end of the third part transmission line section through a second connecting part, and the second end of the third part transmission line section is connected with the second connecting port. Alternatively, the first connection portion and the second connection portion may be connection structures of arbitrary shapes.

As an example, the line width of the first portion of the transmission line segment in the horizontal direction is greater than the line width of the second portion of the transmission line segment in the horizontal direction, and the line width of the second portion of the transmission line segment in the horizontal direction is greater than the line width of the third portion of the transmission line segment in the horizontal direction; alternatively, the line width of the first part of transmission line segment in the horizontal direction is larger than the line width of the third part of transmission line segment in the horizontal direction, and the line width of the third part of transmission line segment in the horizontal direction is larger than the line width of the second part of transmission line segment in the horizontal direction.

Specifically, the second connection port is configured to be connected with a pad interface on the chip, i.e. the second pad interface is configured to be solder-arranged on the chip. The first connection port is configured to connect with a test switching interface, i.e. the first pad interface is configured to connect with a test switching interface (SMA) by means of soldering. The chip is integrated with a power amplifying circuit, a low noise amplifying circuit, a switching circuit or other radio frequency circuits. The test conversion interface is an interface for connecting with external test equipment. Testing of various properties (e.g., loss, gain, power, etc.) of a radio frequency interface circuit or chip may be accomplished through a test conversion interface (SMA).

As an example, to ensure that the characteristic impedance of the first connection port is the same as the characteristic impedance of the first portion transmission line segment 111 and the characteristic impedance of the second connection port is the same as the characteristic impedance of the third portion transmission line segment 113, the implementation makes the line width of the first portion transmission line segment 111 in the horizontal direction configured to be matched with the area size of the first connection port, and the line width of the third portion transmission line segment 113 in the horizontal direction configured to be matched with the area size of the second connection port, so as to reduce the characteristic impedance difference between the first connection port and the second connection port, that is, ensure that the characteristic impedance of the first connection port and the characteristic impedance of the second connection port are the same, so as to reduce the return loss and the insertion loss of the radio frequency connection structure.

In a specific embodiment, the line width of the first part of the transmission line segment in the horizontal direction is larger than the line width of the second part of the transmission line segment in the horizontal direction, and the line width of the second part of the transmission line segment in the horizontal direction is larger than the line width of the third part of the transmission line segment in the horizontal direction.

As an example, the first connection interface is configured to connect with a test transition interface due to the first end of the first portion transmission line segment being connected with the first connection interface; the second end of the third portion transmission line segment is connected to the second connection interface, and the second connection interface is configured to be disposed on the first chip, so, in order to make the line width of the first portion transmission line segment 111 in the horizontal direction be configured to be matched with the area size of the first pad interface, the line width of the third portion transmission line segment 113 in the horizontal direction is configured to be matched with the area size of the second pad interface, and the line width of the first portion transmission line segment in the horizontal direction should be greater than the line width of the third portion transmission line segment in the horizontal direction. And the second part transmission line section is used as a part transmission line section connected between the first part transmission line section and the third part transmission line section, and the line width of the second part transmission line section in the horizontal direction is larger than that of the third part transmission line section in the horizontal direction and smaller than that of the first part transmission line section in the horizontal direction; thereby, the line width of the first transmission line segment connected with the first connection port in the horizontal direction is sequentially increased to the line width of the third transmission line segment connected with the second connection port in the horizontal direction; the problem of discontinuous impedance of the radio frequency connection structure is further improved, and the return loss of the radio frequency connection structure is further optimized.

In a specific embodiment, the at least three layers of ground layers include a first ground layer, a second ground layer and a third ground layer that are disposed from top to bottom, where the third ground layer is a reference layer of the first portion of the transmission line segment, the second ground layer is a reference layer of the second portion of the transmission line segment, and the first ground layer is a reference layer of the third portion of the transmission line segment.

Specifically, since the line width of the third partial transmission line 113 in the horizontal direction is smaller than the line width of the second partial transmission line 112 in the horizontal direction, which is smaller than the line width of the first partial transmission line 111 in the horizontal direction, the impedance of the third partial transmission line 113 is larger than the impedance of the second partial transmission line 112, and the impedance of the second partial transmission line 112 is larger than the impedance of the first partial transmission line 111, resulting in impedance mismatch among the third partial transmission line 113, the second partial transmission line 112, and the first partial transmission line 111. I.e. the smaller the line width of the transmission line segment, the larger the impedance. Therefore, in order to achieve impedance matching between the first partial transmission line segment, the second partial transmission line segment, and the third partial transmission line segment in the present embodiment, the smaller the transmission line segment with a smaller line width is, the smaller the distance from the reference stratum in the vertical direction is, and the larger the transmission line segment with a larger line width is, the larger the distance from the reference stratum in the vertical direction is.

In this embodiment, since the first ground layer, the second ground layer and the third ground layer are disposed from top to bottom, that is, the distance from the first ground layer to the signal transmission layer in the vertical direction is smaller than the distance from the second ground layer to the signal transmission layer in the vertical direction; the distance from the second grounding layer to the signal transmission layer in the vertical direction is smaller than the distance from the third grounding layer to the signal transmission layer in the vertical direction. Therefore, in this embodiment, the third ground layer is a reference layer of the first portion of the transmission line segment, the second ground layer is a reference layer of the second portion of the transmission line segment, and the first ground layer is a reference layer of the third portion of the transmission line segment; therefore, the smaller the line width is, the smaller the distance from the line width to the reference stratum is, and the larger the line width is, the larger the distance from the line width to the reference stratum is, so that impedance matching among the first part of the line width, the second part of the line width and the third part of the line width is realized.

In a specific embodiment, the line width of the third part of the transmission line segment in the horizontal direction is less than or equal to 0.2mm, and the line width of the first part of the transmission line segment in the horizontal direction is greater than or equal to 0.5mm.

As an example, when the line width of the third portion transmission line segment in the horizontal direction is equal to or less than 0.2mm and the line width of the first portion transmission line segment in the horizontal direction is equal to or greater than 0.5mm, that is, the line width size of the first portion transmission line segment in the horizontal direction differs from the line width size of the third portion transmission line segment in the horizontal direction by more than 0.3mm, by adopting the radio frequency connection structure in the present embodiment, the radio frequency transmission line in the radio frequency connection structure includes at least three portion transmission line segments connected in series between the first connection port and the second connection port, and the line widths of each portion transmission line segment in the horizontal direction are different, so that the impedance of the radio frequency connection structure can be made closer to the target impedance (for example: 50Ω), thereby optimizing the return loss of the radio frequency connection structure.

When the radio frequency connection structure works at 4GHz-8GHz, the impedance of the radio frequency connection structure is between [48 ohm-50 ohm ].

Referring to fig. 6 and 7 below, fig. 6 is a graph of impedance simulation results when the radio frequency transmission line includes two transmission line segments connected in series in the related art, and fig. 7 is a graph of impedance simulation results when the radio frequency transmission line includes at least three transmission line segments connected in series in the present embodiment. As can be seen from fig. 6 and 7, compared with the impedance of the related art radio frequency connection structure including only two transmission line segments connected in series in the whole working frequency band, the impedance of the radio frequency connection structure including at least three transmission line segments connected in series in the 4GHz-8GHz frequency band is closer to 50Ω, namely, between [48 ohms-50 ohms ], so that the return loss of the radio frequency connection structure is improved by dividing the radio frequency transmission line into at least three transmission line segments connected in series, each transmission line segment has different line widths in the horizontal direction, so that the impedance can still be kept close to 50Ω when the radio frequency connection structure is operated in the high frequency band (4 GHz-8 GHz), namely, between [48 ohms-50 ohms ]

In a specific embodiment, the outer contour of the first connection portion is an isosceles trapezoid, the isosceles trapezoid includes two first virtual parallel sides and a second virtual parallel side that are parallel to each other, the length of the first virtual parallel side is the same as the line width of the first portion transmission line segment in the horizontal direction, and the length of the second virtual parallel side is the same as the line width of the second portion transmission line segment in the horizontal direction.

As an example, the outer contour of the first connecting portion is an isosceles trapezoid, and the isosceles trapezoid includes two first virtual parallel sides parallel to each other, and the length of the first virtual parallel side is the same as the line width of the first portion transmission line segment 111 in the horizontal direction, and the length of the second virtual parallel side is the same as the line width of the second portion transmission line segment 112 in the horizontal direction.

In a specific embodiment, the outer contour of the first connecting portion is an isosceles trapezoid, and the isosceles trapezoid includes two first virtual parallel sides and a second virtual parallel side that are parallel to each other. The first virtual parallel edge can be used as a first end of the first connecting portion, and the second virtual parallel edge can be used as a second end of the first connecting portion. In the present embodiment, since the line width of the first partial transmission line segment 111 in the horizontal direction is different from the line width of the second partial transmission line segment 112 in the horizontal direction, for example, the line width of the first partial transmission line segment 111 in the horizontal direction is larger than the line width of the second partial transmission line segment 112 in the horizontal direction, and since there is a line width difference between the line width of the first partial transmission line segment 111 in the horizontal direction and the line width of the second partial transmission line segment 112 in the horizontal direction, the present embodiment facilitates matching the impedances of the first partial transmission line segment 111 and the second partial transmission line segment 112 to the target impedance by making the length of the first virtual parallel side the same as the line width of the first partial transmission line segment 111 in the horizontal direction and the line width of the second virtual parallel side the same as the line width of the second partial transmission line segment 112 in the horizontal direction, and making the line width of the first partial transmission line segment 111 in the horizontal direction and the line width of the second partial transmission line segment 112 in the horizontal direction be connected and transited by the first connection portion. Preferably, the target impedance is 50 ohms.

The outline of the second connecting part is an isosceles trapezoid, the isosceles trapezoid comprises a third virtual parallel side and a fourth virtual parallel side which are parallel to each other, the length of the third virtual parallel side is identical to the line width of the second part transmission line section in the horizontal direction, and the length of the fourth virtual parallel side is identical to the line width of the third part transmission line section in the horizontal direction.

As an example, the outer contour of the second connection portion is an isosceles trapezoid, and the isosceles trapezoid includes two third virtual parallel sides parallel to each other, the length of the third virtual parallel side is the same as the line width of the second portion transmission line segment 112 in the horizontal direction, and the length of the fourth virtual parallel side is the same as the line width of the third portion transmission line segment 113 in the horizontal direction.

In a specific embodiment, the outer contour of the second connecting portion is an isosceles trapezoid, and the isosceles trapezoid includes two third virtual parallel sides and a fourth virtual parallel side that are parallel to each other. The third virtual parallel edge can be used as the first end of the second connecting part, and the fourth virtual parallel edge can be used as the second end of the first connecting part. In the present embodiment, since the line width of the second portion transmission line segment 112 in the horizontal direction is different from the line width of the third portion transmission line segment 113 in the horizontal direction, for example, the line width of the second portion transmission line segment 112 in the horizontal direction is larger than the line width of the third portion transmission line segment 113 in the horizontal direction, and since there is a line width difference between the line width of the second portion transmission line segment 112 in the horizontal direction and the line width of the third portion transmission line segment 113 in the horizontal direction, the present embodiment facilitates matching the impedances of the second portion transmission line segment 112 and the third portion transmission line segment 113 to the target impedance by making the length of the third virtual parallel side the same as the line width of the second portion transmission line segment 112 in the horizontal direction and making the length of the fourth virtual parallel side the same as the line width of the third portion transmission line segment 113 in the horizontal direction, and making the line width of the second portion transmission line segment 112 in the horizontal direction and the line width of the third portion transmission line segment 113 in the horizontal direction in the second connection transition through the second connection portion. Preferably, the target impedance is 50 ohms.

In one embodiment, the substrate is an evaluation board. The evaluation board is an EVB board (evaluation board). The interface of the chip is led out and connected to the test conversion interface 200 through the radio frequency transmission line 110 arranged on the evaluation board, and can be used for detecting the functions and performances (such as loss, gain, power and the like) of the chip or checking whether the chip can work normally in various severe environments. The chip may be a chip integrated with a power amplifying circuit, a low noise amplifying circuit, a switching circuit, or other radio frequency circuits.

The embodiment also provides a radio frequency front end module, which comprises the radio frequency connection structure, wherein the radio frequency connection structure comprises a substrate and a radio frequency transmission line, the substrate comprises a signal transmission layer and at least three layers of ground layers, the signal transmission layer and the at least three layers of ground layers are arranged from top to bottom, the radio frequency transmission line is arranged on the signal transmission layer, the radio frequency transmission line comprises at least three parts of transmission line segments connected in series between a first connection port and a second connection port, the first connection port is configured to be connected with a test conversion interface, the second connection port is configured to be connected with a bonding pad interface on a chip, the line width of each part of transmission line segments in the horizontal direction is different, the reference stratum of each part of transmission line segments is one of the at least three layers of ground layers, and the reference stratum of each part of transmission line segments is different; therefore, the first connection port and the second connection port of the radio frequency transmission line can be respectively matched with the test conversion interface and the bonding pad interface on the chip, the problem of discontinuous impedance of the radio frequency connection structure can be solved, and the return loss of the radio frequency connection structure is optimized.

The above embodiments are only for illustrating the technical solution of the present utility model, and not for limiting the same; although the utility model has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present utility model, and are intended to be included in the scope of the present utility model.

Claims (10)

1. The radio frequency connection structure is characterized by comprising a substrate and a radio frequency transmission line, wherein the substrate comprises a signal transmission layer and at least three layers of ground layers, the signal transmission layer and the at least three layers of ground layers are arranged from top to bottom, the radio frequency transmission line is arranged on the signal transmission layer, the radio frequency transmission line comprises at least three parts of transmission line segments connected in series between a first connection port and a second connection port, the first connection port is configured to be connected with a test conversion interface, the second connection port is configured to be connected with a bonding pad interface on a chip, line widths of each part of transmission line segments in the horizontal direction are different, a reference stratum of each part of transmission line segments is one of the at least three layers of ground layers, and a reference stratum of each part of transmission line segments is different.

2. The radio frequency connection structure according to claim 1, wherein a line width in a horizontal direction of a transmission line segment connected to the first connection port sequentially increases to a line width in a horizontal direction of a transmission line segment connected to the second connection port.

3. The radio frequency connection structure according to claim 1, wherein the at least three transmission line segments include a first transmission line segment, a second transmission line segment, and a third transmission line segment connected in series, the first end of the first transmission line segment being connected to the first connection port, the second end of the first transmission line segment being connected to the first end of the second transmission line segment by a first connection, the second end of the second transmission line segment being connected to the first end of the third transmission line segment by a second connection, the second end of the third transmission line segment being connected to the second connection port.

4. The radio frequency connection structure according to claim 3, wherein a line width of the first partial transmission line segment in a horizontal direction is larger than a line width of the second partial transmission line segment in a horizontal direction, and a line width of the second partial transmission line segment in a horizontal direction is larger than a line width of the third partial transmission line segment in a horizontal direction.

5. The radio frequency connection structure according to claim 4, wherein the at least three layers of ground layers include a first ground layer, a second ground layer, and a third ground layer disposed from top to bottom, the third ground layer being a reference layer for the first portion of the transmission line segment, the second ground layer being a reference layer for the second portion of the transmission line segment, and the first ground layer being a reference layer for the third portion of the transmission line segment.

6. The radio frequency connection structure according to claim 5, wherein a line width of the third partial transmission line section in a horizontal direction is 0.2mm or less, and a line width of the first partial transmission line section in a horizontal direction is 0.5mm or more.

7. The radio frequency connection according to claim 1, wherein the impedance of the radio frequency connection is between [48 ohm-50 ohm ] when the radio frequency connection is operating at 4GHz-8 GHz.

8. The radio frequency connection structure according to claim 3, wherein the outer contour of the first connection portion is in the shape of an isosceles trapezoid, the isosceles trapezoid includes two first virtual parallel sides and a second virtual parallel side that are parallel to each other, the length of the first virtual parallel side is the same as the line width of the first partial transmission line segment in the horizontal direction, and the length of the second virtual parallel side is the same as the line width of the second partial transmission line segment in the horizontal direction;

the outline of the second connecting part is an isosceles trapezoid, the isosceles trapezoid comprises a third virtual parallel side and a fourth virtual parallel side which are parallel to each other, the length of the third virtual parallel side is identical to the line width of the second part transmission line section in the horizontal direction, and the length of the fourth virtual parallel side is identical to the line width of the third part transmission line section in the horizontal direction.

9. The radio frequency interconnect structure of claim 1, wherein the substrate is an evaluation board.

10. A radio frequency front end module comprising a radio frequency connection structure according to any of claims 1-9.