EP4632946A1

EP4632946A1 - A radio frequency system and a method for manufacturing the same

Info

Publication number: EP4632946A1
Application number: EP24169241.7A
Authority: EP
Inventors: Christian Geissler
Original assignee: Infineon Technologies AG
Current assignee: Infineon Technologies AG
Priority date: 2024-04-09
Filing date: 2024-04-09
Publication date: 2025-10-15

Abstract

A radio frequency (RF) system is disclosed. The RF system comprises an RF semiconductor chip electrically and mechanically coupled with a printed circuit board. A housing, wherein the RF semiconductor chip and the printed circuit board are inside of the housing. The housing comprises a case and a waveguide antenna, wherein a first side of the waveguide antenna faces the printed circuit board. The case is mounted on the waveguide antenna, and wherein the waveguide antenna is coupled with the RF semiconductor chip to transmit and receive RF signals.

Description

TECHNICAL FIELD

The present disclosure relates to a radio frequency system, in particular to a housing of the radio frequency system.

BACKGROUND

A radio frequency (RF) system e.g., a radar module typically comprises at least one an RF semiconductor chip, a printed circuit board (PCB) on which the at least one RF semiconductor chip is mounted and an antenna. Recently, waveguide antennae have become a focus of interest. The usage of a waveguide antenna can reduce the manufacturing costs for a RF system but due to the voluminous character of the waveguide antenna additional space is required. This becomes even more significant when the RF system includes many RF channels and many antenna elements are required to implement in the waveguide antenna.
Accordingly, it is an object of the present application to provide a concept for an RF system to overcome the above mentioned problems. This object is solved by an RF system according to claim 1 and a method of fabricating an RF system according to claim 15.

SUMMARY

A radio frequency (RF) system is disclosed. The RF system comprises an RF semiconductor chip electrically and mechanically coupled with a printed circuit board. The RF system further comprises a housing, wherein the RF semiconductor chip and the printed circuit board are inside of the housing. The housing comprises a case and a waveguide antenna, wherein a first side of the waveguide antenna faces the printed circuit board. The case is mounted on the waveguide antenna, and wherein the waveguide antenna is coupled with the RF semiconductor chip to transmit and receive RF signals.
A method for manufacturing an RF system is disclosed. The method comprises:

coupling an RF semiconductor chip electrically and mechanically with a printed circuit board;
arranging the RF semiconductor chip and the printed circuit board inside of a housing,

wherein the housing comprises a case and a waveguide antenna,
wherein a first side of the waveguide antenna faces the printed circuit board;
wherein the case is mounted on the waveguide antenna, and
wherein the waveguide antenna is coupled with the RF semiconductor chip to transmit and receive RF signals.

Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like reference numerals refer to similar or identical elements. The elements of the drawings are not necessarily to scale relative to each other. The features of the various illustrated examples can be combined unless they exclude each other.

Figure 1 illustrates a cross-section of a conventional RF system.
Figure 2 illustrates a cross-section of an RF system with a waveguide antenna forming a part of a housing of the RF system.
Figure 3 illustrates a cross-section of an example of an RF semiconductor chip of the RF system of Figure 2.
Figure 4 illustrates a cross-section of a further example of an RF system with a radome as a protection structure.
Figure 5 illustrates a cross-section of a further example of an RF system comprising more than one RF semiconductor chip.
Figure 6 illustrates a flowchart of a method for forming an RF system.

DETAILED DESCRIPTION

Although specific examples have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific examples shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific examples discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.
It should be noted that the description and drawings merely illustrate the principles of the proposed methods and systems. Those skilled in the art will be able to implement various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples and embodiments outlined in the present document are principally intended expressly to be only for explanatory purposes to help the reader in understanding the principles of the proposed methods and systems. Furthermore, all statements herein providing principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.
Figure 1 shows a cross-section of a conventional radio frequency (RF) system 100 having a waveguide antenna 108. The conventional RF system 100 may be radar module suitable for mounting at the place of operation, for example at a car front to determine velocity and distance to objects. The conventional RF system 100 comprises a stack 102 including an RF semiconductor chip 104, a printed circuit board (PCB) 106 and the waveguide antenna 108. The PCB 106 is sandwiched between the RF semiconductor chip 104 and the waveguide antenna 108. A first surface 106a of the PCB 106 faces a frontside 104a of the RF semiconductor chip 104 and a second surface 106b of the PCB 106 opposite to the first surface 106a faces a first side 108a of the waveguide antenna 108. The RF semiconductor chip 104 has solder balls 110 arranged on the frontside 104a of the RF semiconductor chip 104 facing the first surface 106a of the PCB 106 and the solder balls 110 are mounted on the first surface 106a of the PCB 106. The solder balls 110 electrically and mechanically couple the RF semiconductor chip 104 to the PCB 106. The PCB 106 wirelessly couples the RF semiconductor chip 104 with the waveguide antenna 108 and vice-versa. Further, the frontside 104a of the RF semiconductor chip 104 has launchers 130 configured to transmit and receive RF signals to and from the waveguide antenna 108. Radiation elements 112 e.g., antenna elements are arranged on a second side 108b of the waveguide antenna 108 opposite to the first side 108a and are wirelessly coupled with the respective launcher 130 of the RF semiconductor chip 104. Optionally, a heat sink 114 is mounted on a backside 104b of the RF semiconductor chip 104 opposite to the frontside 104a to dissipate the heat from the RF semiconductor chip 104. A thermal interface 116 material may be arranged between the heat sink 114 and the RF semiconductor chip 104.
The stack 102 and the heat sink 114 are enclosed inside a housing 118. The housing 118 comprises two components i.e., a top case 118t and a bottom case 118b opposite to each other. In particular, the sidewalls 120 of top case 118t are mounted onto the sidewalls 122 of the bottom case 118b. The sidewalls 120 of the top case 118t are connected to a top wall 124 of the top case 118t. Similarly, sidewalls 122 of the bottom case 118b are connected to a bottom wall 126 of the bottom case 118b. The walls 124 and 126 of the respective case 118t and 118b faces each other. The housing 118 has dimensions e.g., a height h and a lateral dimension w which also defines the respective dimensions of the conventional RF system 100. The height h of the housing 118 is measured between the top wall 124 of the top case 118t and the bottom wall 126 of the bottom case 118b in a direction orthogonal to the surface 106a or 106b of the PCB 106. The lateral dimension w of the housing 118 is measured between two opposing sidewalls 120, 122 of the top case 118t or bottom case 118b a direction lateral to the surface 106a or 106b of the PCB 106. The heat sink 114 may be arranged between the backside 104b of the RF semiconductor chip 104 and the top wall 124 of the top case 118t.
The waveguide antenna 108 has a lateral dimension w' measured in a direction parallel to the lateral dimension w of the housing 118. The lateral dimension w' of the waveguide antenna 108 defines the number of radiation elements 112 that can be mounted on the second side 108b of the waveguide antenna 108 and consequently, the number of launchers 130 in the conventional RF system 100. The lateral dimension w' of the waveguide antenna 108 is smaller than the lateral dimension w of the housing 118 in order to accommodate the waveguide antenna 108 inside the housing 118. If it is desired to increase the number of RF channels, the number of radiation elements 112 on the second side 108b of the waveguide antenna 108 and consequently, the number of launchers 130 in the conventional RF system 100 needs to be increased. This results in an increase of the lateral dimension w' of the waveguide antenna 108. As a result, if an increase of RF channels is desired, it is required to increase the lateral dimension w of the housing 118 which would lead to a larger lateral dimension of the conventional RF system 100. This may increase the cost of the conventional RF system 100 and may require a larger mounting area on the RF board than usual. Therefore, increasing lateral dimension of the conventional RF system may not be desirable solution to increase the number of RF channels.
Further, the waveguide antenna 108 is fixed on the bottom wall 126 of the bottom case 118b by fixation elements 128 like screws or bumpers. A part of the fixation element 128 separates the second side 108b of the waveguide antenna 108 and the bottom wall 126 of the bottom case 118b by a distance d. The distance d may be up to 1 mm and forms a part of the height h of the housing 118.
The embodiments described herein provides a new concept for an RF system which allows to reduce a lateral dimension of the RF system for a given number of RF channels as compared to the conventional RF system 100. Alternatively, for a given lateral dimension of the housing the RF system can have a greater number of radiation elements on the waveguide antenna as compared to the conventional RF system. This is achieved by a more compact and less voluminous integration of a waveguide antenna by using the waveguide antenna as part of the enclosure of the RF system. Further, the bottom case and the fixation elements can be omitted which brings down the number of components in the RF system and hence the overall cost of the RF system and a height of the RF system as compared to the conventional RF system 100.
In examples according to this concept, the RF system comprises an RF semiconductor chip mounted on a printed circuit board (PCB) with the RF semiconductor chip and the PCB being enclosed inside a housing. The housing has a case which is directly mounted on a waveguide antenna. The waveguide therefore forms a part of the housing. The waveguide antenna has radiation elements wirelessly coupled with the launchers of the RF semiconductor chip. As the waveguide antenna forms a part of the housing and is not arranged inside the housing, space (e.g., a lateral dimension and a height) for the overall RF system can be reduced. Alternatively, a number of radiation elements on the waveguide antenna can be increased for the same lateral dimension as of the conventional RF system 100. By increasing the number of radiation elements, a number of RF channels in the RF system can be increased.
Figure 2 shows an example of an RF system 200 e.g., an RF module comprising an RF semiconductor chip 204 mounted on a PCB 206. The RF semiconductor chip 204 may be configured to operate at a frequency which is in a radio-frequency or microwave frequency range that can generally extend from approximately 10 GHz to approximately 300 GHz. By way of example, the RF semiconductor chip 204 can thus comprise one or a plurality of integrated radio-frequency or microwave circuits that can operate in a frequency range of greater than 10 GHz. The microwave signals transmitted and/or received by the RF semiconductor chip 204 can be millimeter waves, the wavelength of which can be in the millimeter range, for example between approximately 1 mm and approximately 10 mm, which corresponds to a frequency band of approximately 30 GHz to approximately 300 GHz. Such microwave circuits can comprise for example microwave transmitters, microwave receivers, microwave semiconductor packages, microwave sensors, and/or microwave detectors. In one example, the systems described herein can be used for radar applications. Radar microwave systems can be used for example in automotive or industrial applications for distance determining/distance measuring systems. By way of example, automatic vehicle speed regulating systems or vehicle anticollision systems can operate in the microwave frequency range, for example at approximately 24 GHz, 77 GHz or 79 GHz.
A frontside 204a of the RF semiconductor chip 204 faces a first surface 206a of the PCB 206. The RF semiconductor chip 204 has solder balls 208 arranged between the frontside 204a of the RF semiconductor chip 204 and the first surface 206a of the PCB 206. The solder balls 208 electrically couple the RF semiconductor chip 204 and the PCB 206. The solder balls 208 may have diameters in a range between 200 and 400 µm and pitches in a range between of 400 and 600 µm. In some examples, Flip-Chip BGAs (Ball Grid Arrays) or Wirebond-BGA may be used for establishing the electrical and mechanical connection to the PCB. The RF semiconductor chip 204 may have an antenna feed layer coupled to the launchers 210 formed on the front side 204a of the RF semiconductor chip 204. The antenna feed layer is configured to transmit RF signals to the launchers 210 or vice-versa. The launchers 210 are configured to transmit and receive RF signals to a waveguide antenna. The PCB 206 has through-holes 212 formed between the first surface 206a and an opposing second surface 206b of the PCB 206. The through-holes 212 are aligned with the respective launcher 210 of the RF semiconductor chip 204. The through-holes 212 of the PCB 206 are configured to transfer the RF signals via the launchers to and from the RF semiconductor chip 204.
In one example, the RF semiconductor chip 204 may be a bare die, which can contain integrated circuits, passive electronic components, active electronic components, etc. The integrated circuits can be embodied as integrated logic circuits, analog integrated circuits, integrated mixed signal circuits, integrated power circuits, etc. The bare die can be produced from an elemental semiconductor material (e.g. Si, etc.) or from a compound semiconductor material (e.g. GaN, SiC, SiGe, GaAs, etc.). The launchers are formed on a side of the bare die, on which the solder balls are arranged.
In a further example, the RF semiconductor chip 204 may include an RF semiconductor package 300 as shown in Figure 3. The RF semiconductor package 300 includes a semiconductor die 302 and an encapsulation material 306 at least partially surrounding the semiconductor die 302. The RF semiconductor package 300 may for example include a package that is referred to as an enhanced Wafer Level Ball Grid Array (eWLB) package. In one example, the RF semiconductor package 300 has a semiconductor die 302 arranged on a top side 304a of a redistribution layer 304. The semiconductor die 302 and parts of the redistribution layer 304 are surrounded by an encapsulation material 306. The encapsulation material 306 may be epoxy, filled epoxy, glass fiber filled epoxy, thermoset polymers, thermoplastic polymers, or elastomer polymers. A bottom side 306b of the redistribution layer 304 opposite to the top side 304a forms the backside 204b of the RF semiconductor chip 204 package and the solder balls 208 are arranged on the bottom side 304b of the redistribution layer 304. A top side 306a of the encapsulation material 306 facing the sides 304a, 304b of the redistribution layer 304 forms the frontside 204a of the RF semiconductor chip 204.
An electrical contact is established between the semiconductor die 302 and electrically conductive structures of the redistribution layer 304 by the electrical conductive structures. The launchers 210 are formed on the bottom side 304b of the semiconductor die 304. The redistribution layer 304 couples the launchers 210 with the bare die 302 through the electrically conductive structures. This allows the transmission of the RF signals between the semiconductor die 302 and the launchers 210. The solder balls 208 are arranged on the bottom side 304b of the redistribution layer 304. However other examples may include other configurations and arrangements of the launchers. For example, the launchers may be arranged on a separate substrate which is mechanically connected to the semiconductor die 302 including the RF circuitry or to the redistribution layer 304 for example a flip-chip ball grid array package.
Referring again to Figure 2, the RF system 200 has a housing 214 which encloses the RF semiconductor chip 204 and the PCB 206. The housing 214 may completely surround the PCB 206 and the semiconductor chip 204. The housing 214 includes a case 216 and a waveguide antenna 218. The waveguide antenna 218 is arranged in a direction parallel to the PCB 206 in particular, a first side 218a of the waveguide antenna 218 faces the surfaces 206a and 206b of the PCB 206. The waveguide antenna 218 is mounted to the case 216 to form one side of the housing 214. The case 216 may be completely open at this side of the housing 214. At the location where the waveguide antenna 218 is mounted to the case 216, the case 216 may have a same lateral dimension as the waveguide antenna 218 or a lateral dimension of the case 216 may not differ more than 10% or 5% or 1% from the lateral dimension of the waveguide antenna 218. The waveguide antenna 218 may form a wall portion of the housing 214 such that no other housing wall is provided and required at the side of the housing 214 at which the waveguide antenna 218 is located. The waveguide antenna 218 provides mechanical protection from external influences for the PCB 206 and the semiconductor chip 204. The waveguide antenna 218 may have a thickness in a range of 5 mm to 10 mm measured between the first side 218a and an opposing second side 218b of the waveguide antenna 218 in a direction orthogonal to the surface 206a or 206b of the PCB 206. Therefore, the waveguide antenna 218 can be regarded as a three-dimensional waveguide antenna which is cost-effective, provides higher RF signal gain and high potential for optimization. The PCB 206 is coupled with the waveguide antenna 218 by screws, glue, soldering or fixing with a clip etc.. The case 216 may be a hollow case made of a metal e.g., aluminum or plastic and sidewalls 220 of the case 216 can be glued, screwed, clipped or glued on the first side 218a of the waveguide antenna 218. The RF semiconductor chip 204 and the PCB 206 are enclosed between the first side 218a of the waveguide antenna 218 and the case 216.
In some examples, the sidewalls 220 of the case 216 may face the sidewalls 222 of the waveguide antenna 218 connecting the first side 218a and the second side 218b of the waveguide antenna 218. In other words, the case 216 may be fixed to the waveguide antenna 218 by press-fit.
The waveguide antenna 218 has a body 224 and a waveguide 226 extending inside the body 224. For example, the waveguide 226 may extend between and in a direction lateral to the first and second sides 218a, 218b of the waveguide antenna 218. The body 224 of the waveguide antenna 218 may comprise a plastic material which may be molded. In some examples, multiple pre-molded parts may be mounted together to form the waveguide antenna 218. In other examples, the body 224 of the waveguide antenna 218 may be formed by a metal block. The waveguide antenna 218 may be a slotted waveguide antenna, for example a plastic slotted waveguide antenna or a metal slotted waveguide antenna. The waveguide 226 is a hollowwaveguide and has a first opening 226a and a second opening 226b on the first side 218a and the second side 218b of the waveguide antenna 218 respectively. The walls of the waveguide 226 are metalized to minimize the loss of the RF signal travelling inside the waveguide 226.
Further, the RF system 200 has a radiation element 228 which may be formed by slots on the second side 218b of the waveguide antenna 218. The radiation element 228 is configured to transmit and receive RF signals to and from the RF semiconductor chip 204. The first opening 226a of the waveguide antenna 218 faces the respective through-hole 212 of the PCB 206. The second opening 226b of the waveguide 226 is coupled with the radiation element 228. In other words, the radiation element 228 is wirelessly coupled with the respective launcher 210 of the RF semiconductor chip 204 via the waveguide 226 and the through-hole 212 of the PCB 206.
The waveguide antenna 218 may comprise a further waveguide 226 and a further radiation element 228. The further radiation element 228 is wirelessly coupled with the respective launcher 210 of the RF semiconductor chip 204 via the further waveguide 226 and the respective through-hole 212 of the PCB 206.
The housing 214 has a lateral dimension w measured between two opposing sidewalls 222 of the waveguide antenna. By incorporating the waveguide antenna 218 as a part of the housing 214, the number of radiation elements 228 on the waveguide antenna 218 as compared to the waveguide antenna 108 of the conventional RF system 100 of Figure 1, can be increased without increasing the lateral dimension w of the housing 214.
For the same number of radiation elements 228 as compared to the conventional RF system 100, a smaller lateral dimension of the housing 214 can be achieved compared to the conventional housing shown in Fig. 1 (assuming the same waveguide antenna is used).
As the waveguide antenna forms 208 forms a part of the housing 214, a height h' of the RF system 200 can be made smaller than the height h of the conventional RF system 100 by at least the distance d (see Figure 1). The height h' of the RF system 200 is measured between the second side 218b of the waveguide antenna 218 and a top wall of the case 214 facing the backside 204b of the RF semiconductor chip 204.
In some examples, a protection structure 230 may be disposed over the second side 218b of the waveguide antenna 218 to protect the waveguide antenna 218 from contamination e.g., humidity and dust particles etc. As shown in Figure 2, the protection structure 230 may be a protection layer e.g., a lid or a protection foil. The protection layer may be made of mold tape, DAF tape, glass, acrylic glass, or plastic foil.
As shown in Figure 2, a heat sink 232 is mounted between the backside 204b of the RF semiconductor chip 204 and the top wall the case 216. A thermal interface material 234 may be arranged between the heat sink 232 and the RF semiconductor chip 204 to transfer the heat from the RF semiconductor chip 204 to the heat sink 232. The thermal interface material 234 may comprise thermal paste, thermal grease, thermal adhesives, thermal tapes, metal thermal interface materials with a typical thermal conductivity in a range of 1 to 7 W/mK.
Figure 4 shows a further example of an RF system 400. The RF system 400 may include some or all features of the RF system 200 and will be described in regards of differences only. The protection structure is a radome 402 in this example. In some examples, the radome 402 may be designed to have a lens effect to disperse or focus RF signals transmitted or received by the RF semiconductor chip 204 or the radiation elements 228. The RF signals transmitted from the radome 402 can be focused into a narrow beam or dispersed over a wide range. Alternatively, the RF signals received by the radome 402 can be focused to the radiation elements 228. The shape of the radome 402 can be flexibly chosen according to the arrangement of the radiation elements 228. As an example, the shape of the radome 402 may be hemispherical as shown in Figure 5. However, other shapes of the radome 402 e.g., rectangular may also be chosen. Furthermore, the radome may have a spacing from the waveguide antenna in order to reduce backscattering effects.
In some examples, the protection structure may comprise the protection layer in combination with the radome.
Figure 5 shows a further example of an RF system 500 which may include some or all features of the RF system 400. The number of radiation elements 228 on the waveguide antenna 218 may go beyond the number of launchers 210 in the RF semiconductor chip 204. The RF system 500 may comprise a further RF semiconductor chip 502. The further RF semiconductor chip 502 is similar to the RF semiconductor chip 204. The further RF semiconductor chip 502 is mounted on the second surface 206b of the PCB 206 and coupled with the respective radiation elements 228 in same manner as the RF semiconductor chip 204. The heat sink 232 may extend further on a backside 502b of the further RF semiconductor chip 502 and dissipate the heat generated by the both RF semiconductor chips 204, 502. Or a further heat sink may be attached between the further RF semiconductor chip 502 and the case 216 of the housing 214.
Figure 6 shows a flow chart of a method 600 to form an RF system. The method 600 comprises the following steps:
Step 602: coupling an RF semiconductor chip electrically and mechanically with a printed circuit board.

Step 604: arranging the RF semiconductor chip and the printed circuit board inside of a housing,
- wherein the housing comprises a case and a waveguide antenna,
- wherein a first side of the waveguide antenna faces the printed circuit board;
- wherein the case is mounted on the waveguide antenna, and
- wherein the waveguide antenna is coupled with the RF semiconductor chip to transmit and receive RF signals.

As described above, the new concept allows to decrease the size of the housing compared to the conventional approach. For a same lateral dimension of the housing, the number of radiation elements on the waveguide antenna can be increased and consequently, the number of RF channels in the RF semiconductor chip. The height of the RF system can be made smaller as compared to the height of the conventional RF system by omitting the bottom case and the fixation elements. The new concept reduces the number of components, cost and dimensions of the RF systems as compared to the conventional RF system.
Further, the RF system has a protection structure disposed on the radiation elements to protect them against humidity, dust etc. The protection structure can be flexibly chosen e.g., as a protection layer or a radome or both depending upon the application of the RF system.
The following examples pertain to further aspects of the disclosure:

Example 1 discloses a radio frequency (RF) system comprising:
- an RF semiconductor chip electrically and mechanically coupled with a printed circuit board;
- a housing, wherein the RF semiconductor chip and the printed circuit board are inside of the housing,
  - wherein the housing comprises a case and a waveguide antenna,
  - wherein a first side of the waveguide antenna faces the printed circuit board.
  - wherein the case is mounted on the waveguide antenna, and
  - wherein the waveguide antenna is coupled with the RF semiconductor chip to transmit and receive RF signals.
Example 2 discloses the RF system according to example 1, wherein the case is mounted on the first side of the waveguide antenna.
Example 3 discloses the RF system according to example 2, wherein a first side of the RF semiconductor chip is electrically and mechanically coupled with a first surface of the printed circuit board and wherein a heat sink is mounted between a second side of the RF semiconductor chip opposite to the first side and the case of the housing.
Example 4 discloses the RF system according to example 1 to 3, further comprising a further RF semiconductor chip, wherein a first side of the further RF semiconductor chip is electrically and mechanically coupled with the first surface of the printed circuit board and wherein the heat sink is mounted between a second side of the further RF semiconductor chip opposite to the first side and the case of the housing.
Example 5 discloses the RF system according to example 4, wherein the RF semiconductor chip comprises a bare die and the further RF semiconductor chip comprises a bare die.
Example 6 discloses the RF system according to example 4, wherein the RF semiconductor chip comprises a semiconductor package and the further RF semiconductor chip comprises a semiconductor package.
Example 7 discloses the RF system according to examples 1 to 6, wherein the waveguide antenna comprises at least one waveguide extending between the first side and a second side of the waveguide antenna opposite to the first side, wherein a first opening of the at least one waveguide is at the first side of the waveguide antenna and a second opening of the at least one waveguide is at the second side of the waveguide antenna.
Example 8 discloses the RF system according to example 7, wherein the printed circuit board comprises holes between the first surface and a second surface of the printed circuit board opposite to the first surface and wherein the holes are configured to wirelessly couple the at least one waveguide and the RF semiconductor chip.
Example 9 discloses the RF system according to example 8, further comprising an antenna feed layer configured to transfer RF signals from the RF semiconductor chip to a launcher for transferring the RF signals to the first opening of the at least one waveguide of the waveguide antenna via holes of the printed circuit board.
Example 10 discloses the RF system according to any preceding examples, wherein the waveguide antenna comprises a plastic slotted waveguide antenna or a metal slotted waveguide antenna.
Example 11 discloses the RF system according to any preceding examples, wherein the waveguide antenna comprises a three-dimensional waveguide antenna.
Example 12 discloses the RF system according to any preceding examples, wherein the waveguide antenna comprises radiation elements at the second side of the waveguide antenna and a protection structure is disposed over the second side of the waveguide antenna to protect the waveguide antenna from contamination.
Example 13 discloses the RF system according to example 12, wherein the protection structure comprises an electrically insulating and RF transparent medium.
Example 14 discloses the RF system according to example 12 to 13, wherein the protection structure is a protection layer and/or a radome.
Example 15 discloses a method for manufacturing an RF system comprising:
- coupling an RF semiconductor chip electrically and mechanically with a printed circuit board;
- arranging the RF semiconductor chip and the printed circuit board inside of a housing,
  - wherein the housing comprises a case and a waveguide antenna, wherein a first side of the waveguide antenna faces the printed circuit board;
  - wherein the case is mounted on the waveguide antenna, and
  - wherein the waveguide antenna is coupled with the RF semiconductor chip to transmit and receive RF signals.

Claims

A radio frequency (RF) system (200, 400, 500) comprising:
- an RF semiconductor chip (204) electrically and mechanically coupled with a printed circuit board (206);

- a housing (214), wherein the RF semiconductor chip (204) and the printed circuit board (206) are inside of the housing (214),
wherein the housing (214) comprises a case (216) and a waveguide antenna (218), wherein a first side (218a) of the waveguide antenna (218) faces the printed circuit board (206).

wherein the case (216) is mounted on the waveguide antenna (218), and wherein the waveguide antenna (218) is coupled with the RF semiconductor chip (204) to transmit and receive RF signals.
The RF system (200, 400, 500) according to claim 1, wherein the case (216) is mounted on the first side (218a) of the waveguide antenna (218).
The RF system (200, 400, 500) according to claim 2, wherein a first side (204a) of the RF semiconductor chip (204) is electrically and mechanically coupled with a first surface (206a) of the printed circuit board (206) and wherein a heat sink (232) is mounted between a second side (204b) of the RF semiconductor chip (204) opposite to the first side (204a) and the case (216) of the housing (214).
The RF system (200, 400, 500) according to claim 1 to 3, further comprising a further RF semiconductor chip (502), wherein a first side (502a) of the further RF semiconductor chip (502) is electrically and mechanically coupled with the first surface (206a) of the printed circuit board (206) and wherein the heat sink (232) is mounted between a second side (502b) of the further RF semiconductor chip (502) opposite to the first side (502a) and the case (216) of the housing (214).
The RF system (200, 400, 500) according to claim 4, wherein the RF semiconductor chip (204) comprises a bare die and the further RF semiconductor chip (502) comprises a bare die.
The RF system (200, 400, 500) according to claim 4, wherein the RF semiconductor chip (204) comprises a semiconductor package and the further RF semiconductor chip (502) comprises a semiconductor package.
The RF system (200, 400, 500) according to claims 1 to 6, wherein the waveguide antenna (218) comprises at least one waveguide (226) extending between the first side (218a) and a second side (218b) of the waveguide antenna (218) opposite to the first side (218a), wherein a first opening (226a) of the at least one waveguide (226) is at the first side (218a) of the waveguide antenna (218) and a second opening (226b) of the at least one waveguide (226) is at the second side (218b) of the waveguide antenna (218).
The RF system (200, 400, 500) according to claim 7, wherein the printed circuit board (206) comprises holes (212) between the first surface (206a) and a second surface (206b) of the printed circuit board (206) opposite to the first surface (206a) and wherein the holes (212) are configured to wirelessly couple the at least one waveguide (226) and the RF semiconductor chip (204, 502).
The RF system (200, 400, 500) according to claim 8, further comprising an antenna feed layer configured to transfer RF signals from the RF semiconductor chip (204, 502) to a launcher (210) for transferring the RF signals to the first opening (226a) of the at least one waveguide (226) of the waveguide antenna (218) via holes (212) of the printed circuit board (206).
The RF system (200, 400, 500) according to any preceding claims, wherein the waveguide antenna (218) comprises a plastic slotted waveguide antenna or a metal slotted waveguide antenna.
The RF system (200, 400, 500) according to any preceding claims, wherein the waveguide antenna (218) comprises a three-dimensional waveguide antenna.
The RF system (200, 400, 500) according to any preceding claims, wherein the waveguide antenna (218) comprises radiation elements (228) at the second side (218b) of the waveguide antenna (218) and a protection structure (230) is disposed over the second side (218b) of the waveguide antenna (218) to protect the waveguide antenna (218) from contamination.
The RF system (200, 400, 500) according to claim 12, wherein the protection structure (230) comprises an electrically insulating and RF transparent medium.
The RF system (200, 400, 500) according to claim 12 to 13, wherein the protection structure (230) is a protection layer and/or a radome (402).
A method (600) for manufacturing an RF system comprising:
- coupling an RF semiconductor chip electrically and mechanically with a printed circuit board;

- arranging the RF semiconductor chip and the printed circuit board inside of a housing,
wherein the housing comprises a case and a waveguide antenna,

wherein a first side of the waveguide antenna faces the printed circuit board; wherein the case is mounted on the waveguide antenna, and

wherein the waveguide antenna is coupled with the RF semiconductor chip to transmit and receive RF signals.