Signal device including a slot transition between substrate integrated waveguide and signal generator

Abstract

An illustrative example electronic device (22) includes a signal generator (24) having at least one conductive output member (32, 34). A substrate integrated waveguide (SIW) (26) includes a substrate (36) and a plurality of conductive members (38) disposed within the substrate (36). The substrate (36) includes a slot (40) in an outer surface (31) of the substrate (36). The slot (40) is positioned adjacent to the at least one conductive output member (32, 34) of the signal generator (24) such that a signal from the signal generator (24) is coupled into the substrate integrated waveguide (26) through the slot (40).

Description

[0001] This application is a divisional application of the invention application with application date of March 9, 2020, application number CN202010156272.6, and title “Signal device including a narrow slot transition between a substrate integrated waveguide and a signal generator”. Technical Field

[0002] The present invention relates to a signal device comprising a substrate-integrated waveguide. Background Art

[0003] Modern passenger vehicles include an increasing number of electronic devices. Technological advances have made it possible to integrate a wide variety of systems into vehicles. For example, various sensor configurations have been developed to provide drivers with assistance or information about the vehicle's surroundings. Various object detection and sensing technologies can provide functions such as parking assistance and collision avoidance.

[0004] Advances in radio frequency signal technology have enabled the development of complex system-on-a-chip integrated circuits. Functionality required for environmental sensing or communication can be implemented within integrated circuit components. For example, monolithic microwave integrated circuits (MMICs) operate at microwave frequencies and can be used to generate radar detection signals.

[0005] Various antennas that can be used for automotive radar systems are known, including substrate integrated waveguides (SIWs), for example. These devices are useful in vehicle environments because they are generally efficient and relatively low-cost. One challenge associated with using substrate integrated waveguides for vehicle-based sensing or communication systems is the connection between the signal-generating integrated circuit components and the substrate integrated waveguides. For example, microstrip (microwave transmission strip) or coplanar waveguide microwave transmission lines (lines) can provide the interface between the integrated circuit components and the substrate integrated waveguides. This connection has disadvantages, such as the need for microwave components that match the field configuration unique to each transmission line. The transition associated with such microwave components increases microwave losses and introduces microwave reflections, which may limit bandwidth and affect the ability to produce such systems. When using microstrip, bandwidth may be limited by the requirement for ground connection from the integrated circuit component connector through the substrate integrated waveguide substrate to the metal layer on the substrate. Relatively expensive blind via processes are typically used to make this connection. Summary of the Invention

[0006] An illustrative example electronic device includes a signal generator having at least one conductive output member. A substrate-integrated waveguide (SIW) includes a substrate and a plurality of conductive members within the substrate. The substrate includes a slot within one of its outer surfaces. The slot is positioned adjacent to the at least one conductive output member of the signal generator such that a signal from the signal generator is coupled through the slot into the SIW.

[0007] In an exemplary embodiment having one or more features of the device of the previous paragraph, the at least one electrically conductive output member includes two output members, and a portion of the slot is located between the two output members.

[0008] In an exemplary embodiment having one or more features of the apparatus of any preceding paragraph, the signal of the signal generator comprises a differential signal.

[0009] In an exemplary embodiment having one or more features of the apparatus of any preceding paragraph, the two output members each comprise a solder ball.

[0010] In an exemplary embodiment having one or more features of the apparatus of any preceding paragraph, the substrate-integrated waveguide has a length corresponding to a direction of signal propagation along the substrate-integrated waveguide, the length of the slot is parallel to the length of the substrate-integrated waveguide, and the length of the slot corresponds to half a wavelength of a signal generated by the signal generator.

[0011] In an exemplary embodiment having one or more features of the apparatus of any preceding paragraph, the substrate includes a second slot proximate one end of the slot, and the second slot is transverse to the slot.

[0012] In an exemplary embodiment having one or more features of the device of any preceding paragraph, the second slot is perpendicular to the slot.

[0013] In an exemplary embodiment having one or more features of the device of any preceding paragraph, at least one electrically conductive output member is between the second slot and the other end of the slot.

[0014] In an exemplary embodiment having one or more features of the device of any preceding paragraph, the at least one conductive output member includes two output members, the second slot has a length, and the length of the second slot is at least as long as the center-to-center spacing between the two output members.

[0015] Exemplary embodiments having one or more features of the device of any preceding paragraph include a tip portion near one end of the slot having a tip portion width wider than the width of the slot and a tip portion length shorter than the length of the slot.

[0016] In an exemplary embodiment having one or more features of the device of any preceding paragraph, the slot and the tip comprise openings through an outer surface of the substrate.

[0017] In an exemplary embodiment having one or more features of the apparatus of any preceding paragraph, the outer surface of the substrate comprises a conductive metal.

[0018] In an exemplary embodiment having one or more features of the device of any preceding paragraph, the outer surface includes a transverse slot near a first end of the slot, the outer surface includes an end portion near a second end of the slot, at least one conductive output member is closer to the first end of the slot than to the second end of the slot, and the transverse slot is located on a side of the at least one conductive output member opposite the end portion.

[0019] In an exemplary embodiment having one or more features of the device of any preceding paragraph, the at least one conductive output member includes two output members with a space therebetween, and a portion of the slot is located within the space between the two output members.

[0020] In an exemplary embodiment having one or more features of the apparatus of any preceding paragraph, the width of the slot is smaller than the spacing.

[0021] An illustrative example method of manufacturing an electronic device includes forming a slot on an outer surface of a substrate, the substrate including a plurality of conductors, the substrate and the plurality of conductors establishing a substrate-integrated waveguide (SIW); and placing a signal generator adjacent to the outer surface of the substrate, proximate to the slot, the signal generator having at least one conductive output member positioned adjacent to the slot such that a signal from the signal generator is coupled through the slot into the SIW.

[0022] In an exemplary embodiment having one or more features of the method of the preceding paragraph, forming the slot includes etching a metal layer on an outer surface of the substrate.

[0023] An exemplary embodiment having one or more features of the method of any preceding paragraph includes forming the transverse slot proximate one end of the slot and forming the end portion proximate an opposite end of the slot.

[0024] In an exemplary embodiment having one or more features of the method of any preceding paragraph, the signal of the signal generator has a differential signal, and forming the slot includes establishing a length of the slot corresponding to half the wavelength.

[0025] In an exemplary embodiment having one or more features of the method of any preceding paragraph, the at least one conductive output member includes two output members with a space therebetween, and placing the signal generator adjacent to the outer surface of the substrate includes positioning a portion of the slot within the space between the two output members.

[0026] The various features and advantages of at least one disclosed example embodiment will become apparent to those skilled in the art from the following detailed description, which is briefly described in the drawings that accompany the detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1A vehicle comprising a signaling device designed according to an embodiment of the invention is diagrammatically shown.

[0028] Figure 2 A signaling device designed according to an embodiment of the present invention is shown diagrammatically.

[0029] Figure 3 Shown Figure 2 Selected features of an embodiment.

[0030] Figure 4 It is along Figure 2 A cross-sectional view taken along line 4-4 in FIG. DETAILED DESCRIPTION

[0031] Embodiments of the present invention provide a signal device with a unique connection between a signal generator output and a substrate integrated waveguide (SIW). Embodiments of the present invention eliminate the interconnect transition between the signal generator and the substrate integrated waveguide, which maximizes system performance while minimizing complexity.

[0032] Figure 1 A vehicle 20 is shown including a plurality of signaling devices, schematically shown at 22. In some examples, the signaling devices 22 are configured as radar signaling devices for detecting objects near the vehicle 20 based on signals transmitted by the devices 22. The exemplary signaling devices 22 may be used for parking assist, collision avoidance, and other object detection features on passenger vehicles.

[0033] like Figures 2 to 4 As shown, an embodiment of the signal device 22 includes a signal generator 24 and a substrate integrated waveguide (SIW) 26. The signal generator 24 includes a plurality of solder balls 30 secured to a metal layer 31 located on one surface or side of the SIW 26. The signal generator 24 includes at least one conductive signal output member. The exemplary embodiment shown includes conductive signal output members 32 and 34. The two signal output members allow the output of the signal generator 24 to be a differential signal. The signal output members 32 and 34 include solder balls. The circuitry for generating the signal is not shown and may include known radar signal generation circuitry or components.

[0034] Substrate integrated waveguide 26 includes substrate 36, which may comprise a known dielectric material. Substrate 36 has a metal layer 31 on one side and a metal layer 37 on the opposite side. In some embodiments, metal layers 31 and 37 comprise copper.

[0035] A plurality of conductors 38 are located in substrate 36 to create a substrate-integrated waveguide waveguide. Conductor 38 may, for example, comprise open or filled vias between metal layers 31 and 37. In the example shown, the arrangement of conductors 38 is consistent with the arrangement of vias in known substrate-integrated waveguide configurations.

[0036] The substrate-integrated waveguide 26 includes a slot 40 on its outer surface for coupling the signal from the signal generator 24 into the substrate-integrated waveguide 26. The slot 40 has a depth extending through the metal layer 31. The length of the slot 40 corresponds to half the wavelength of the signal generated by the signal generator 24, and the length of the slot 40 is parallel to the length of the substrate-integrated waveguide. This slot length need not, and in many embodiments, will not, be exactly half the signal wavelength. Instead, the slot length corresponding to half the wavelength will be slightly adjusted or tuned to achieve the desired performance. In an example embodiment involving an 85 GHz signal, the wavelength in the dielectric material of the substrate 36 is approximately 2 mm, as the dielectric constant of this material is approximately 3. In the example embodiment, the length of the slot 40 is approximately 1 mm. This slot length facilitates the transition to ultra-wideband signals in the substrate-integrated waveguide 26. Signal devices including slots designed similarly to those in the example embodiment shown are useful for signal frequencies between 65 GHz and 90 GHz.

[0037] The width of the slot 40 is approximately equal to the spacing between the conductive signal output members 32 and 34. In the example shown, the width of the slot 40 is at least 0.1 mm and is no wider than the spacing between the conductive signal output members 32 and 34. In some embodiments, the slot width is based on the spacing between the weld materials of the signal output members 32 and 34 after welding.

[0038] A stub 42 at one end of the slot 40 includes an opening through the metal layer 31 that is wider and shorter than the slot 40. The stub 42 effectively provides an additional resonance at a lower frequency and extends the resonance provided by the slot 40. The stub 42 helps create an ultra-wideband transition (transition) into the substrate-integrated waveguide 26.

[0039] like Figure 3 As best shown in FIG. 4 , a portion of slot 40 is located between signal output members 32 and 34. A transverse slot 44 is located at the end of slot 40 proximal to signal output members 32 and 34 and opposite the end of slot 40 including head 42. With reference to the direction of signal propagation through substrate-integrated waveguide 26, transverse slot 44 is located behind signal output members 32 and 34. Transverse slot 44 effectively expands the resonant bandwidth of slot 40.

[0040] In the example shown, the length of transverse slot 44 is perpendicular to the length of slot 40. The perpendicular arrangement of slots 40 and 44 minimizes mutual coupling in the respective electric fields of the slots. The electric field of transverse slot 44 is perpendicular to the electric field of slot 40. The length of transverse slot 44 is selected based on the size or placement of conductive signal output members 32 and 34. In some embodiments, the length of transverse slot 44 is no wider than the spacing between conductive vias 38 near transverse slot 44 and no less than the center-to-center distance between signal output members 32 and 34.

[0041] In some example embodiments, the slot 40 , the end portion 42 , and the transverse slot 44 are formed in the metal layer 31 by etching away some of the metal.

[0042] One feature of the exemplary device configuration is that multiple slots 40, corresponding to respective signal generator output members, can be supported on the same substrate. The isolation between adjacent substrate-integrated waveguides having slots 40 can be on the order of -34 dB. The ability to include multiple signal sources and multiple substrate-integrated waveguides on a single substrate can facilitate a greater variety of device functionality within tighter packaging constraints.

[0043] Slot 40 couples energy from signal output members 32 and 34 directly into substrate-integrated waveguide 26 without any high transition losses. Slot 40, with its transverse slot 44 and end portion 42, provides an ultra-wideband transition. Furthermore, slot 40 is useful for differential signals, which microstrip lines cannot handle because they are limited to single-ended signals. While a vehicle radar detector is considered as an example for discussion purposes, embodiments of the present invention are applicable to a variety of signal or detection devices.

[0044] The foregoing description is illustrative rather than restrictive in nature. Variations and modifications to the disclosed examples will become apparent to those skilled in the art without necessarily departing from the spirit of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.

Claims

1. An electronic device comprising: a signal generator having two conductive output members; as well as A substrate-integrated waveguide comprises a substrate and a plurality of conductor members in the substrate, the substrate comprising a slot in one outer surface of the substrate and a terminal portion near one end of the slot, a terminal portion width of the terminal portion being wider than a width of the slot and a terminal portion length of the terminal portion being shorter than a length of the slot, and a portion of the slot being positioned between the two conductive output members of the signal generator such that a differential signal of the signal generator is coupled into the substrate-integrated waveguide through the slot.

2. The device according to claim 1, wherein The two output members include solder balls, respectively.

3. The device according to claim 1, wherein The substrate integrated waveguide has a length corresponding to a signal propagation direction along the substrate integrated waveguide; The length of the slot is parallel to the length of the substrate integrated waveguide; and The length of the slot corresponds to half the wavelength of the signal generated by the signal generator.

4. The device according to claim 1, wherein The base plate includes a second slot proximate one end of the slot; and The second slot is transverse to the slot.

5. The device according to claim 4, characterized in that The second slot is perpendicular to the slot.

6. The device according to claim 5, characterized in that The conductive output member is between the second slot and the other end of the slot.

7. The device according to claim 4, wherein The second slot has a length; and The length of the second slot is at least as long as the center-to-center spacing between the two output members.

8. The device according to claim 1, wherein The slot and the tip portion include openings through an outer surface of the base plate.

9. The device according to claim 8, wherein The outer surface of the substrate includes a conductive metal.

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