Radio frequency front end and electronic equipment including same

Abstract

The embodiment of the present invention relates to the field of radio frequency technology, and discloses a radio frequency front end and an electronic device including the same. The radio frequency front end includes: a radio frequency substrate, a through metal line, and a coupling metal line; the through metal line and the coupling metal line are both arranged on the same routing layer of the radio frequency substrate, and the through metal line and the coupling metal line form a directional coupler in an inductive electromagnetic coupling manner. In this embodiment, the through metal line and the coupling metal line of the directional coupler are formed on the same routing layer of the radio frequency substrate, so that the cost of the radio frequency front end can be further reduced while satisfying the coupling performance.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of radio frequency technology, and in particular to a radio frequency front end and an electronic device comprising the same. Background Art

[0002] A directional coupler is a radio frequency microwave passive device that places two transmission lines in close proximity so that the power on one transmission line can be transmitted to another transmission line through electromagnetic coupling. As a universal radio frequency device, the radio frequency directional coupler can be used for signal isolation, separation and mixing, such as power monitoring, source output power stabilization, signal source isolation, transmission and reflection sweep frequency testing, etc. The main technical indicators of radio frequency directional couplers are directivity, standing wave ratio, coupling degree, and insertion loss. Directional couplers are composed of transmission lines. Coaxial lines, rectangular waveguides, circular waveguides, strip lines, and microstrip lines can all constitute directional couplers, so from the structural point of view, there are many types of directional couplers, and the differences are very large. However, from the perspective of its coupling mechanism, it can be mainly divided into four types, namely small hole coupling, parallel coupling, branch coupling, and matched double T.

[0003] Since the space is relatively limited in the RF front-end of mobile phones such as LTE (Long Term Evolution, LTE for short) and 5G, it has always been a design difficulty in the industry to ensure small size and insertion loss while meeting the excellent coupler performance. In today's large-scale mass-produced LTE RF front-end modules, there are three main types of couplers: independent devices implemented by LTCC (Low Temperature Co-fired Ceramic, LTCC for short) packaging technology, couplers implemented by multi-layer metal on the chip, and couplers implemented by multi-layer metal on the PCB. However, since the LTCC RF coupler is an independent packaged device, it is generally large in size and difficult to integrate into RF front-end modules such as LTE and 5G. At the same time, after integration, the loss is generally high due to the long interconnection between different devices. The coupler function can be realized through on-chip design, but the chip area is expensive and it is easy to interfere with other circuits in the chip. The couplers implemented in wireless modules today are mostly couplers implemented by winding multi-layer metal (generally four layers or more). This type of coupler has better performance and lower cost than other existing solutions.

[0004] The inventors have discovered that there are at least the following problems in the prior art: as the commercialization of wireless modules becomes increasingly advanced, the demand for cost control is still increasing, and existing implementation methods of directional couplers are not conducive to further reducing the cost of implementing the RF front end. Summary of the invention

[0005] The purpose of an embodiment of the present invention is to provide a radio frequency front end and an electronic device comprising the same. By forming a straight-through metal line and a coupling metal line of a directional coupler on the same routing layer of a radio frequency substrate, the cost of the radio frequency front end can be further reduced while satisfying the coupling performance.

[0006] To solve the above technical problems, an embodiment of the present invention provides a radio frequency front end, comprising: a radio frequency substrate, a through metal line and a coupling metal line; the through metal line and the coupling metal line are both arranged on the same routing layer of the radio frequency substrate, and the through metal line and the coupling metal line form a directional coupler in an inductive electromagnetic coupling manner.

[0007] An embodiment of the present invention further provides an electronic device, comprising the radio frequency front end as described above.

[0008] Compared with the prior art, the embodiment of the present invention sets the through metal line and the coupling metal line of the directional coupler on the same routing layer of the RF substrate, that is, the directional coupler is realized through a layer of substrate. Therefore, this embodiment breaks through the existing directional coupler design method, combines the directional coupler with the RF substrate in the RF front end, and forms them on the same routing layer of the RF substrate, thereby reducing complexity and cost while meeting the performance of the RF front end.

[0009] In addition, the through metal line includes M through segments, and the coupled metal line includes N coupling segments; M and N are both natural numbers greater than or equal to 1; the M through segments and the N coupling segments are arranged at intervals, and the mutually spaced through segments or coupling segments are respectively connected by jumpers; the RF front end also includes a load impedance device and a RF chip; the load impedance device is arranged on the RF substrate or the RF chip, and is connected to the load end of the directional coupler, which is conducive to further reducing costs.

[0010] In addition, the through metal line is a through section, and the coupling metal line includes a first coupling section and a second coupling section; the through section is U-shaped, the first coupling section is U-shaped and is located on the outside of the through section, the second coupling section is located on the inside of the through section, and the first coupling section and the second coupling section are connected through a jumper; the first end of the through section forms the input end of the directional coupler, the second end of the through section forms the output end of the directional coupler, the idle end of the first coupling section forms the coupling end of the directional coupler, and the idle end of the second coupling section forms the load end of the directional coupler, thereby providing an implementation method for the present invention.

[0011] In addition, the through metal line includes a first through section and a second through section; the first through section and the second through section are both U-shaped, and one end of the first through section and the second through section are connected by a jumper; the coupling metal line includes a third coupling section, a fourth coupling section and a fifth coupling section; the third coupling section, the fourth coupling section and the fifth coupling section are all U-shaped; one end of the third coupling section, the fourth coupling section and the fifth coupling section are respectively connected by a jumper; wherein the second through section is located outside the first through section, the third coupling section is located inside the first through section, the fourth coupling section is located between the first through section and the second through section, the fifth coupling section is located outside the second through section, the idle end of the first through section forms the input end of the directional coupler, and the idle end of the second through section forms the output end of the directional coupler; the idle end of the third coupling section forms the coupling end of the directional coupler, and the idle end of the fifth coupling section forms the load end of the directional coupler, thereby providing another implementation of the present invention.

[0012] In addition, the through metal line is a straight through section, and the coupling metal line includes a sixth coupling section and a seventh coupling section; the sixth coupling section and the seventh coupling section both extend in a straight direction, and the sixth coupling section and the seventh coupling section are distributed in parallel on both sides of the straight through section, and one end of the sixth coupling section and the seventh coupling section are connected by a jumper; wherein the first end of the straight through section forms the input end of the directional coupler, the second end of the straight through section forms the output end of the directional coupler, and the idle ends of the sixth coupling section and the seventh coupling section respectively form the coupling end and the load end of the directional coupler, thereby providing another implementation method for the present invention.

[0013] In addition, the through metal line includes a third through section and a fourth through section; the third through section and the fourth through section both extend in a straight direction and are parallel to each other; the coupling metal line includes an eighth coupling section, a ninth coupling section and a tenth coupling section; the eighth coupling section, the ninth coupling section and the tenth coupling section are arranged in parallel and spaced apart from the third through section and the fourth through section; one end of the third through section and the fourth through section are connected by a jumper, and the idle ends of the third through section and the fourth through section respectively form the input end and the output end of the directional coupler; one end of the eighth coupling section, the ninth coupling section and the tenth coupling section are respectively connected by a jumper, wherein the ninth coupling section is located between the third through section and the fourth through section, and the idle ends of the eighth coupling section and the tenth coupling section respectively form the coupling end and the load end of the directional coupler, thereby providing another implementation of the present invention.

[0014] In addition, the width of the through metal line is greater than the width of the coupling metal line, and the thickness of the through metal line is the same as the thickness of the coupling metal line, which is beneficial to reducing insertion loss.

[0015] In addition, the RF substrate is a double-layer structure consisting of a top layer and a bottom layer, wherein the top layer is a signal layer and the bottom layer is a ground layer, which has lower cost than the existing structure with more than two layers.

[0016] In addition, the through metal line and the coupling metal line are both microstrip lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0018] Figure 1 is a schematic structural diagram of a directional coupler in a radio frequency front end according to a first embodiment of the present invention;

[0019] Figure 2 is a schematic structural diagram of a second coupling section of a directional coupler in a radio frequency front end according to a first embodiment of the present invention;

[0020] Figure 3 is a schematic structural diagram of a directional coupler in a radio frequency front end according to a second embodiment of the present invention;

[0021] Figure 4 is a schematic structural diagram of a directional coupler in a radio frequency front end according to a third embodiment of the present invention;

[0022] Figure 5 4 is a schematic diagram of the structure of a directional coupler in a radio frequency front end according to a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the following will be described in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present invention, many technical details are provided in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can be implemented.

[0024] The first embodiment of the present invention relates to a radio frequency front end. Figure 1, the RF front end includes: an RF substrate 1, a straight-through metal line 2 and a coupling metal line 3. The straight-through metal line 2 and the coupling metal line 3 are both arranged on the same routing layer of the RF substrate 1, and the straight-through metal line 2 and the coupling metal line 3 form a directional coupler in an inductive electromagnetic coupling manner. Compared with the prior art, the embodiment of the present invention sets the straight-through metal line and the coupling metal line of the directional coupler on the same routing layer of the RF substrate, that is, the directional coupler is realized through a layer of substrate. Therefore, this embodiment breaks through the existing directional coupler design method, combines the directional coupler with the RF substrate in the RF front end, and forms them on the same routing layer of the RF substrate, thereby reducing complexity and cost while satisfying the performance of the RF front end. The implementation details of the RF front end of this embodiment are described in detail below. The following content is only the implementation details provided for the convenience of understanding, and is not necessary for the implementation of this solution.

[0025] Specifically, the straight-through metal line includes M straight-through segments, and the coupled metal line includes N coupled segments. M and N are both natural numbers greater than or equal to 1. The M straight-through segments and the N coupled segments are arranged at intervals, and the mutually spaced straight-through segments or coupled segments are connected by jumpers respectively. The RF front end also includes a load impedance device and an RF chip. The load impedance device is arranged on the RF substrate or the RF chip and is connected to the load end of the directional coupler. Among them, the RF substrate 1 can be used for circuit interconnection of various functional devices in the RF front end. This embodiment does not impose specific restrictions on the shape, number and specific arrangement of the straight-through metal line and the coupled metal line, as long as the coupling performance required by the design can be met. In practical applications, the load impedance device is generally a resistor with an impedance of 50 ohms. The load impedance device can be implemented in the RF chip, thereby further saving the RF substrate area. At the same time, the load end Z of the directional coupler is connected through the second jumper 41. L In one example, the resistor can also be soldered on the surface of the RF substrate wiring layer by surface mount technology (SMT). This embodiment does not impose any specific restrictions on the implementation and installation of the load impedance device.

[0026] Please continue reading Figure 1 The directional coupler shown is integrated on the RF substrate 1 in the RF front end. The through metal line 2 is a through section, which is a continuous through section, that is, the through section itself is continuous in spatial distribution and is not disconnected. The coupling metal line 3 includes a first coupling section 301 and a second coupling section 302. The through section is roughly U-shaped, for example Figure 1The first coupling section 301 is also U-shaped and is located outside the straight-through section, so that the coupling degree can be improved while saving PCB area. It should be noted that in practical applications, the straight-through metal line 2 and the coupling metal line 3 can also adopt other shapes, and the present invention does not make specific restrictions on this, as long as the coupling performance required by the design can be met. Figure 1 The opening of the U-shaped straight-through section faces rightward, but the opening position of the straight-through section is not specifically limited. The second coupling section 302 is located inside the straight-through section. The first coupling section 301 and the second coupling section 302 are connected by a jumper. Specifically, Figure 1 The first coupling section 301 and the second coupling section 302 are connected by a first jumper 40. The first end of the through section forms the input end In of the directional coupler, the second end of the through section forms the output end Out of the directional coupler, the idle end of the first coupling section 301 forms the coupling end CPL_O of the directional coupler, and the idle end of the second coupling section 302 forms the load end Z of the directional coupler. L The idle end of the first coupling section 301, ie, the coupling end CPL_O of the directional coupler, is adjacent to the input end In of the through section.

[0027] See also Figure 2 The second coupling section 302 includes: a first subsection 3021, a second subsection 3022, a third subsection 3023, a fourth subsection 3024, and a fifth subsection 3025, which are sequentially connected in a counterclockwise direction. The second subsection 3022 is vertically connected to the first subsection 3021, the fourth subsection 3024 is parallel to the second subsection 3022, the third subsection 3023 is vertically connected to the second subsection 3022 and one end of the fourth subsection 3024, and the fifth subsection 3025 is parallel to the third subsection 3023 and connected to the other end of the fourth subsection 3024. In this embodiment, the idle end of the fifth subsection 3025 is connected to an end adjacent to the first coupling section 301 through the first jumper 40.

[0028] In this embodiment, the distances between the first coupling section 301 and the second coupling section 302 and the portions of the through metal line 2 that are parallel to each other are the same.

[0029] In this embodiment, the through metal line 2 and the coupled metal line 3 are both implemented by microstrip lines, that is, the microstrip lines are arranged on the same routing layer of the RF substrate 1. This embodiment does not specifically limit the implementation method of the through metal line 2 and the coupled metal line 3. In practical applications, the through metal line 2 and the coupled metal line 3 can also be implemented by strip lines, as long as the performance required by the design can be met.

[0030] The widths of the through metal line 2 and the coupling metal line 3 have a certain influence on the performance of the directional coupler. In this embodiment, the width of the through metal line 2 is greater than the width of the coupling metal line 3, thereby making the insertion loss of the directional coupler lower.

[0031] The thickness of the through metal line 2 and the coupling metal line 3 has a certain influence on the performance of the directional coupler. In an example, the thickness of the through metal line 2 and the coupling metal line 3 are the same, so that the directional coupler in the RF front end has better coupling performance.

[0032] In this embodiment, in order to meet the RF front-end application requirements of the frequency band between 500Mhz and 2.7Ghz (i.e., LTE and 5G frequency bands), the inventor further proposed the preferred size of the directional coupler based on the aforementioned directional coupler structure based on the same layer of RF substrate. Specifically, the width of the straight metal wire 2 is 80 microns, and the width of the coupling metal wire 3 is 50 microns, that is, the width of the first coupling section 301 and the second coupling section 302 are both 50 microns, the thickness of the straight metal wire 2 and the coupling metal wire 3 are both 20 microns, the distance between the first coupling section 301 and the second coupling section 302 and the straight metal wire 2 is 50 microns, and the total length of the straight metal wire 2 is 1.5 millimeters (mm). The directional coupler with the above preferred size can fully meet the application requirements of the LTE and 5G frequency bands and has better performance. Among them, since the transmission path of the straight metal wire 2 is only one and the length is very short, the loss is very low. For example, the insertion loss of the directional coupler of the RF front end is only 0.1dB (decibel), and the insertion loss is very low. At the same time, the directivity of the directional coupler is 15-20dB and the coupling degree is 20-25dB. Therefore, the directional coupler is a low-cost, high-performance device, especially suitable for the RF front end of LTE and 5G frequency bands.

[0033] In practical applications, the RF substrate can be a double-layer structure consisting of a top layer and a bottom layer. The top layer is a signal layer and the bottom layer is a ground layer, but the present invention does not specifically limit the structure of the RF substrate. In this way, the through metal line 2 and the coupling metal line 3 of the directional coupler are both formed on the signal layer of the RF substrate. This implementation method can further reduce the cost of the RF front end, and greatly reduce the integration and implementation complexity of the directional coupler, and has a strong application prospect.

[0034] Compared with the prior art, this embodiment forms the through metal line and the coupling metal line of the directional coupler on the same routing layer of the RF substrate, so that the directional coupler can be realized with fewer layers of the RF substrate, which is conducive to reducing the cost of the RF front end. At the same time, compared with the directional coupler of the LTCC structure, it is not only easier to integrate, but also has better performance. Compared with the directional coupler integrated in the chip, the cost is lower. Therefore, when the directional coupler is integrated, the RF front end of this embodiment has lower cost and higher performance, and has great application prospects.

[0035] The second embodiment of the present invention relates to a radio frequency front end. The second embodiment is substantially the same as the first embodiment, and the main difference is that in the second embodiment, the number of segments of the through metal line and the coupling metal line is increased, thereby enriching the embodiments of the present invention.

[0036] See also Figure 3 , the straight-through metal line 2 in the RF front end of this embodiment includes a first straight-through section 201 and a second straight-through section 202. The first straight-through section 201 and the second straight-through section 202 are both U-shaped. The coupling metal line 3 includes: a third coupling section 303, a fourth coupling section 304 and a fifth coupling section 305. The third coupling section 303, the fourth coupling section 304 and the fifth coupling section 305 are all U-shaped. Among them, the second straight-through section 202 is located on the outside of the first straight-through section 201, the third coupling section 303 is located on the inside of the first straight-through section 201, the fourth coupling section 304 is located between the first straight-through section 201 and the second straight-through section 202, and the fifth coupling section 305 is located on the outside of the second straight-through section 202. One end of the first straight-through section 201 and the second straight-through section 202 are connected by a jumper, and one end of the third coupling section 303, the fourth coupling section 304 and the fifth coupling section 305 are respectively connected by a jumper. Specifically, the first straight-through section 201 and the second straight-through section 202 are connected through the third jumper 42, the third coupling section 303 and one end of the fourth coupling section 304 are connected through the fourth jumper 43, and the fourth coupling section 304 and one end of the fifth coupling section 305 are connected through the fifth jumper 44. The idle end of the first straight-through section 201 forms the input end In of the directional coupler, the idle end of the second straight-through section 202 forms the output end Out of the directional coupler, the idle end of the third coupling section 303 forms the coupling end CPL_O of the directional coupler, and the idle end of the fifth coupling section 305 forms the load end Z of the directional coupler. L .

[0037] Compared with the above-mentioned embodiments, this embodiment further enriches the implementation methods of the directional coupler by increasing the number of segments of the through metal lines and the coupling metal lines.

[0038] The third embodiment of the present invention relates to a radio frequency front end. The third embodiment is substantially the same as the first embodiment, and the main difference is that the shapes of the through metal line and the coupling metal line in the third embodiment are different from those in the first embodiment, thereby enriching the embodiments of the present invention.

[0039] See also Figure 4 , the straight-through metal line 2 in the RF front end of this embodiment is a straight-through section, and the coupling metal line 3 includes a sixth coupling section 306 and a seventh coupling section 307. The sixth coupling section 306 and the seventh coupling section 307 both extend in a straight direction, and the sixth coupling section 306 and the seventh coupling section 307 are distributed in parallel on both sides of the straight-through section. One end of the sixth coupling section 306 and the seventh coupling section 307 are connected by a jumper, specifically, the adjacent ends of the sixth coupling section 306 and the seventh coupling section 307 are connected by a sixth jumper 45. Among them, the first end of the straight-through section forms the input end In of the directional coupler, the second end of the straight-through section forms the output end Out of the directional coupler, and the idle end of the sixth coupling section 306 forms the load end Z of the directional coupler. L , the idle end of the seventh coupling section 307 forms the coupling end CPL_O of the directional coupler.

[0040] Compared with the first embodiment, this embodiment provides a directional coupler with a linear structure, further enriching the implementation methods of the directional coupler.

[0041] The fourth embodiment of the present invention relates to a radio frequency front end. The fourth embodiment is substantially the same as the third embodiment, and the main difference is that the fourth embodiment increases the number of segments of straight-through metal lines and coupling metal lines, thereby enriching the embodiments of the present invention.

[0042] See also Figure 5, the straight-through metal line 2 in the RF front end of this embodiment includes a third straight-through section 203 and a fourth straight-through section 204. The third straight-through section 203 and the fourth straight-through section 204 both extend in a straight direction and are parallel to each other. The coupling metal line 3 includes: an eighth coupling section 308, a ninth coupling section 309 and a tenth coupling section 310. The eighth coupling section 308, the ninth coupling section 309 and the tenth coupling section 310 are arranged in parallel and spaced apart from the third straight-through section 203 and the fourth straight-through section 204. One end of the third straight-through section 203 and the fourth straight-through section 204 are connected by a jumper, and one end of the eighth coupling section 308, the ninth coupling section 309 and the tenth coupling section 310 are connected by jumpers respectively. Specifically, one end of the third straight-through section 203 and the fourth straight-through section 204 are connected by a seventh jumper 46, one end of the eighth coupling section 308 and the ninth coupling section 309 are connected by a ninth jumper 48, and one end of the ninth coupling section 309 and the tenth coupling section 310 are connected by an eighth jumper 47. The idle end of the third through section 203 forms the input end In of the directional coupler, the idle end of the fourth through section 204 forms the output end Out of the directional coupler, and the idle end of the eighth coupling section 308 forms the load end Z of the directional coupler. L , the idle end of the tenth coupling section 310 forms the coupling end CPL O of the directional coupler.

[0043] Compared with the third embodiment, this embodiment further enriches the implementation methods of the directional coupler by increasing the number of segments of the through metal lines and the coupling metal lines.

[0044] The fifth embodiment of the present invention relates to an electronic device, comprising a radio frequency front end as described in any one of the first to fourth embodiments. The electronic device is, for example, a smart phone, a tablet computer, and a car audio and video, and this embodiment does not specifically limit the type of the electronic device.

[0045] Compared with the prior art, this embodiment integrates a low-cost, high-performance directional coupler in the RF front end of the electronic device, which is beneficial to reducing the overall cost of the electronic device without affecting the RF performance of the electronic device, thereby making the electronic device highly competitive in the market.

[0046] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A radio frequency front end, characterized in that: include: RF substrate, through metal lines, and coupled metal lines; The through metal line and the coupling metal line are both arranged on the same routing layer of the radio frequency substrate, and the through metal line and the coupling metal line form a directional coupler in an inductive electromagnetic coupling manner; The directional coupler is combined with the RF substrate in the RF front end and formed on the same routing layer of the RF substrate. The RF substrate is used for circuit interconnection of various functional devices in the RF front end. The through metal line includes M through segments, and the coupled metal line includes N coupled segments; M and N are both natural numbers greater than or equal to 1; the M through segments and the N coupled segments are arranged at intervals, and the mutually spaced through segments or coupled segments are respectively connected by jumpers; the RF front end also includes a load impedance device and a RF chip; the load impedance device is arranged on the RF substrate or the RF chip, and is connected to the load end of the directional coupler; The through metal line includes a first through section and a second through section; the first through section and the second through section are both U-shaped, and one end of the first through section and the second through section are connected by a jumper; the coupling metal line includes a third coupling section, a fourth coupling section and a fifth coupling section; the third coupling section, the fourth coupling section and the fifth coupling section are all U-shaped; one end of the third coupling section, the fourth coupling section and the fifth coupling section are respectively connected by a jumper; wherein the second through section is located outside the first through section, the third coupling section is located inside the first through section, the fourth coupling section is located between the first through section and the second through section, the fifth coupling section is located outside the second through section, the idle end of the first through section forms the input end of the directional coupler, and the idle end of the second through section forms the output end of the directional coupler; the idle end of the third coupling section forms the coupling end of the directional coupler, and the idle end of the fifth coupling section forms the load end of the directional coupler.

2. The radio frequency front end according to claim 1, characterized in that: The width of the through metal line is greater than the width of the coupling metal line, and the thickness of the through metal line is the same as that of the coupling metal line.

3. The radio frequency front end according to claim 1, characterized in that: The radio frequency substrate is a double-layer structure consisting of a top layer and a bottom layer, wherein the top layer is a signal layer and the bottom layer is a ground layer.

4. The radio frequency front end according to claim 1, characterized in that: The through metal line and the coupling metal line are both microstrip lines.

5. An electronic device, characterized in that: Comprising a radio frequency front end as described in any one of claims 1-4.

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