Modular low-loss insert

Abstract

Radio frequency systems for advanced driver assistance systems (ADAS) can include a mix of high frequency (e.g., above 1 GHz) analog components and low frequency digital devices mounted on one main circuit board. Cost savings can be realized by providing high frequency signal paths on an insert circuit board that is mounted to the main circuit board and couples devices that require high frequency signaling (e.g., distributing local oscillator signals to several devices that form part of a cascaded radar system). The insert is made of a specialized material suitable for routing high frequency signals with low loss, while the main circuit board can be made of a commodity material suitable for lower frequency applications.

Description

Technical Field

[0001] The embodiments of the subjects described herein relate to radio frequency circuits and systems. Background Technology

[0002] Circuits requiring the distribution of high-frequency (e.g., 1 GHz and above) signals among multiple components are becoming increasingly common in industrial and consumer applications. For example, many passenger vehicles are equipped with Advanced Driver Assistance Systems (ADAS), which typically include radar transceivers and processors that implement obstacle avoidance, adaptive cruise control, and other collision avoidance features. Cascaded radar systems, where the operation of multiple individual radar transceivers is synchronized with each other, can be a cost-effective way to provide enhanced radar performance by achieving features such as increased detection range and improved beamforming. Summary of the Invention

[0003] In an example embodiment, a system includes: a circuit board providing a first set of electrical interconnects; a first set of electronic devices and a second set of electronic devices mechanically coupled to the circuit board, wherein the first set of electronic devices is configured to communicate with the second set of electronic devices via the first set of electrical interconnects; and an insert substrate mechanically and electrically coupled to the circuit board, providing a second set of electrical interconnects configured to route radio frequency (RF) signals to the second set of electronic devices; wherein the insert substrate is characterized by a loss tangent of the RF signal at a desired operating frequency of the second set of electronic devices; and wherein the circuit board is characterized by a second loss tangent of the RF signal at the desired operating frequency of the second set of electronic devices, the second loss tangent being greater than the first loss tangent. Attached Figure Description

[0004] This disclosure is illustrated by means of examples, embodiments, etc., and is not limited to the accompanying drawings, in which similar reference numerals indicate similar elements. Elements in the drawings are shown for simplicity and clarity, and these elements are not necessarily drawn to scale. The drawings, together with the detailed description, are incorporated in and form a part of this specification, and are used to further illustrate examples, embodiments, etc., and to explain various principles and advantages based on this disclosure, as shown in the drawings:

[0005] Figure 1 This is a schematic plan view of a system including a low-loss RF insert according to one or more embodiments.

[0006] Figure 2A yes Figure 1 A schematic cross-sectional view of the system.

[0007] Figure 2B Is with Figure 2AA schematic cross-sectional diagram of the system related to the system.

[0008] Figure 2C Is with Figure 2A A schematic cross-sectional diagram of the system related to the system.

[0009] Figure 3A This is a schematic plan view of an RF insert suitable for use in one or more embodiments, the RF insert including an RF coupler formed using substrate integrated waveguide (SIW) technology.

[0010] Figure 3B yes Figure 3A A schematic plan view of the insert.

[0011] Figure 4 This is a schematic plan view of an RF insert suitable for use in one or more embodiments, the RF insert comprising... Figure 3A and Figure 3B This includes RF couplers associated with integrated amplifiers. Detailed Implementation

[0012] The following detailed descriptions are provided as examples for illustrative purposes and are not intended to limit the invention or its application and uses. Furthermore, they are not intended to be construed as being bound by any explicit or implicit theory presented in the foregoing technical field, background art, or the following detailed descriptions.

[0013] For simplicity and clarity, the elements in the figures are not necessarily drawn to scale. For example, the dimensions of some elements or areas in the figures may be enlarged relative to other elements or areas to aid in understanding the embodiments of the invention. Unless otherwise stated, directional references, such as “top,” “bottom,” “left,” “right,” “above,” “below,” etc., are not intended to claim any preferred orientation, but are for illustrative purposes and refer to the orientation corresponding to one or more figures. Furthermore, for clarity, well-known and conventional features may be omitted from the figures and detailed descriptions.

[0014] A cascaded radar system in which a single local oscillator (LO) signal is distributed to multiple synchronously operating transceivers has been adapted for use in ADAS systems for passenger vehicles and other applications where system performance must typically be balanced against manufacturing costs, space constraints, and ease of integration with other electronic and mechanical systems. To address these constraints, multiple radar transceivers can be packaged on a circuit board directly attached to a 3D antenna assembly on the top or bottom surface of the contact circuit board.

[0015] Such radar systems typically employ local oscillator frequencies exceeding 10 GHz. However, many commonly used circuit board materials (e.g., epoxy-glass composites, such as FR-4) exhibit high losses at signal frequencies in the GHz range, exhibiting frequency-dependent losses that can also lead to unwanted signal dispersion. These properties can impose limitations on the maximum length of signal distribution lines and can make it difficult to achieve phase matching between multiple signal lines, which is often a requirement in cascaded radar systems where the received LO signals at each transceiver should be in phase with each other. One solution to these challenges is to use different circuit board materials with better loss characteristics in selected frequency bands. However, this significantly increases system costs.

[0016] Therefore, the apparatus and methods disclosed herein enable the design, manufacture, and integration of cascaded radar systems and related systems by reducing the need for expensive, low-loss circuit board materials through the formation of important signal routes on modular inserts that are easily connected to larger circuit boards made of more cost-effective materials.

[0017] According to these principles, Figure 1 A simplified schematic top view of an example radar system is shown. System 100 is built on a carrier 102 (e.g., a printed circuit board or other suitable substrate) and includes a first set of components 110 and a second set of components 120 that are interconnected to each other and to a processor 150. Processor 150 includes a communication interface 155 for connecting system 100 to other devices and systems. For example, processor 150 may provide a signal indicating that an obstacle has been detected to an ADAS system controller in a passenger vehicle. The first set of components 110 can be any components that do not require a low-loss high-frequency signal path, while the second set of components 120 are components that require low-loss signal distribution at high frequencies (e.g., above 1 GHz). Figure 1 In this example, system 100 includes four radar transceivers 120A, 120B, 120C, and 120D (depicted as separately packaged devices mechanically and electrically coupled to substrate 102). Radar transceiver 120A may be configured as a master transceiver to distribute local oscillator (LO) signals, and transceivers 120B, 120C, and 120D may be auxiliary transceivers configured to receive externally generated LO signals.

[0018] System 100 includes an insert 130 comprising a four-way RF coupler 135 (which may also be referred to as a power divider or splitter) configured to split a signal received at the input port 136 of the coupler 135 (e.g., the LO signal generated by transceiver 120A) (labeled 'IN') into four individual signals (labeled 'OUT') at four corresponding output ports 137 of the coupler. The RF coupler 135 is depicted as a microstrip coupler, but any suitable coupler and combination thereof can be used, including stripline couplers, waveguide couplers, etc., as non-limiting examples.

[0019] Insert 130 is made of a material with appropriately low loss and dispersion in a selected operating frequency band. The material of insert 130 can be selected such that the effective path length between the input port 136 of RF coupler 135 and each output port 137 of RF coupler 135 is equal (and therefore, at the selected operating frequency or operating band of RF coupler 135, the phase of the LO signal at each output port 137 of coupler 135 is equal within an acceptable error tolerance of, for example, 5° or less). As a non-limiting example, suitable dielectric materials for inserts such as insert 130 include PTFE, other low-loss polymer materials, various ceramics, etc. For example, PTFE-based circuit boards can exhibit loss tangents far below 0.01 or even 0.001 at frequencies much higher than 1 GHz (including frequencies used for LO signals in automotive radar).

[0020] In one or more embodiments, the insert (e.g., insert 130) is a circuit board provided with conventional electrical contacts that allow the insert to be mechanically and electrically coupled to a larger circuit board or other substrate (e.g., carrier 102) using conventional techniques. For example, as a non-limiting example, insert 130 may be provided with solder balls arranged in a ball grid array (BGA), insert 130 may have contacts compatible with surface mount solder reflow processes, and so on.

[0021] It should be understood that System 100 is a non-limiting example for illustrative purposes. For example, nothing herein is intended to limit the use of the embodiments to systems including radar transceivers and LO signal distribution. Following a similar principle, inserts according to the embodiments disclosed herein may include any suitable number of signal paths and means (including, as non-limiting examples, clock distribution paths, clock buffers, etc.) and any other suitable active or passive components.

[0022] Figure 2A , Figure 2B and Figure 2CThis is a cross-sectional view illustrating features of a system, such as system 100, in one or more embodiments. In system 200A, two devices 120 (e.g., radar transceiver chips) are shown mounted on carrier 102 and coupled to insert 130 (depicted as a circuit board bonded to carrier 102 via solder balls) via electrical interconnects 295 disposed on and within carrier 102. In one or more embodiments, such connections are made entirely via conductive traces on the surface of the carrier (e.g., the top surface 103 (or bottom surface 104) of carrier 102). Device 110 is also shown mounted on the top surface 103 of carrier 102.

[0023] In system 200B, carrier 102 is modified to include a transmitting structure 205 beneath each device 205. The transmitting structure 205 extends through carrier 102 and includes conductive sidewalls sized and arranged to guide wireless signals (e.g., radar pulses or radar return signals) transmitted or received by each device 120 away from (or toward) each device 120 and carrier 102. In one or more embodiments, a planar or three-dimensional antenna assembly may be coupled to the surface of carrier 102 beneath device 120.

[0024] In system 200C, insert 130 is mounted on the bottom surface 104 of carrier 102 below device 120 and between two transmitting structures 205. In one or more embodiments, an antenna structure or other structure may be mounted together with insert 130 on the bottom surface of carrier 102. When the antenna structure or fixture is coupled to carrier 102, the antenna structure or fixture may include a recess or opening disposed above insert 130.

[0025] The insert according to one or more embodiments may include any suitable structure for coupling RF signals (e.g., LO signals) between devices such as radar transceivers (e.g., device 120). For example, Figure 3A This is a plan view of an insert 330 having an RF coupler 335 based on a substrate integrated waveguide (SIW). The RF coupler 335 guides RF signals within the volume of the insert 330 via a waveguide having sidewalls defined by metallized vias 395, which are arranged such that they behave like solid conductive surfaces over the designed operating bandwidth of the RF coupler 335. The RF coupler 335 is covered above and below the vias 395 by a ground plane or other suitable conductive surface. (Dashed outline indicates...) Figure 3A The coverage area of ​​the metallized surface 338 that forms the top surface of the RF coupler 335 is not directly shown in the figure. Figure 3B It is coupler 335 along Figure 3AThe cross-sectional view of line 399 shows the position of the input port 336 and output port 337 of the RF coupler 335, as well as the top surface 338 and bottom surface 339, relative to the through-hole 395 forming the sidewall of the RF coupler 335.

[0026] It should be understood that, by way of non-limiting example, RF coupler 335 is depicted as a SIW coupler, and any suitable coupling structure may be used in one or more embodiments. For example, a dielectric waveguide coupler may be used with a suitable transition structure for coupling signals between the waveguide coupler and metallic waveguides and other interconnects. It should be understood that nothing herein is intended to limit the embodiments to any particular coupler or interconnect architecture. Therefore, it should be understood that non-limiting examples of suitable structures include stripline structures, dielectric waveguide structures, conductive waveguide structures, coaxial structures, and any suitable combinations of such structures.

[0027] As described above, the insert according to one or more embodiments may include additional active means. For example, Figure 4 An insert including an amplifier 490 is shown, which is coupled to an input port 436 of an RF coupler 435, depicted as a SIW coupler having sidewalls formed using a through-hole 495 (e.g., through-hole 395). The amplifier 490 is configured to receive and amplify a LO signal via the input port 436, and then couple the amplified LO signal to an output port 437 of the RF coupler 435. In one or more embodiments, the amplifier or other active device, such as the amplifier 490, may be configured to be connected via a power supply voltage terminal (e.g., ...). Figure 4 The middle mark is 'V' DD The power supply voltage terminal (port 491) receives power and is configured to couple to the carrier to which the insert is connected (e.g., carrier 102). Similarly, the insert according to one or more embodiments may include any other suitable connections and signal distributions (e.g., ground or other reference voltage connections as a non-limiting example).

[0028] It should be understood that insert 435 is intended as a non-limiting example. Following these principles, inserts according to one or more embodiments may include multiple active devices, such as amplifier 490. Similarly, in one or more embodiments, inserts may include passive devices (e.g., capacitors, inductors, resistors, etc.).

[0029] example

[0030] The features of the embodiments can be understood with the help of one or more of the following examples:

[0031] Example 1: A system, apparatus, or method includes: a circuit board providing a first set of electrical interconnects. A first set of electronic devices and a second set of electronic devices are mechanically coupled to the circuit board. The first set of electronic devices is configured to communicate with the second set of electronic devices via the first set of electrical interconnects. An insert substrate is mechanically and electrically coupled to the circuit board and provides a second set of electrical interconnects configured to route radio frequency (RF) signals to the second set of electronic devices. The insert substrate is characterized by a first loss tangent of the RF signal at a selected operating frequency of the second set of electronic devices. The circuit board is characterized by a second loss tangent of the RF signal at a selected operating frequency of the second set of electronic devices, the second loss tangent being greater than the first loss tangent.

[0032] Example 2: A system, apparatus, or method according to Example Clause 1, wherein the second set of electronic devices includes two or more radar transceivers configured to operate coherently using local oscillator (LO) signals distributed to each radar transceiver via the second set of electrical interconnects.

[0033] Example 3: The system, apparatus, or method according to Example 1 or Example 2 further includes a set of transmitter structures disposed within a carrier, the set of transmitter structures being configured to direct RF signals away from or toward a radar transceiver.

[0034] Example 4: A system, apparatus, or method according to any one of Examples 1 to 3, wherein a first set of devices is disposed on the top surface of a carrier, and the system, apparatus, or method further includes an antenna structure mechanically coupled to the bottom surface of the carrier and configured to couple RF signals to or from a radar transceiver via a transmitter structure.

[0035] Example 5: A system, apparatus, or method according to any one of Examples 1 to 4, wherein the selected operating frequency of the second set of electronic devices is the LO frequency of a local oscillator; and wherein the second set of electrical interconnects forms a passive RF power divider, the passive RF power divider being configured to receive an LO signal at an input port of the power divider at the LO frequency and to distribute the LO signal to a set of output ports of the power divider.

[0036] Example 6: A system, apparatus, or method according to any one of Examples 1 to 5, wherein the insert substrate includes an amplifier configured to generate an amplified LO signal and couple the amplified LO signal to a radar transceiver via a passive RF power divider.

[0037] Example 7: A system, apparatus or method according to any one of Examples 1 to 6, wherein the insert substrate is characterized by a loss tangent of less than 0.01 at frequencies above 10 GHz.

[0038] Example 8: A system, apparatus, or method according to any one of Examples 1 to 7, wherein the RF power divider and the insert substrate are jointly configured and arranged such that the corresponding phases of the LO signals measured at each output of the power divider are equal within a tolerance of less than five degrees.

[0039] Example 9: A system, apparatus, or method according to any one of Examples 1 to 8, wherein the RF power divider is a substrate integrated waveguide (SIW) power divider.

[0040] Example 10: A system, apparatus or method according to any one of Examples 1 to 8, wherein the RF power divider is a stripline power divider.

[0041] Example 11: A system, apparatus or method according to any one of Examples 1 to 8, wherein the RF power divider is a microstrip power divider.

[0042] Example 12: A system, apparatus or method according to any one of Examples 1 to 8, wherein the RF power divider is a coplanar waveguide power divider.

[0043] Example 13: A system, apparatus or method according to any one of Examples 1 to 8, wherein the RF power divider is a hollow conductive waveguide power divider.

[0044] Example 14: A system, apparatus or method according to any one of Examples 1 to 8, wherein the RF power divider is a dielectric waveguide power divider.

[0045] Example 15: A system, apparatus or method according to any one of Examples 1 to 8, wherein the RF power divider is a coaxial power divider.

[0046] The foregoing specific embodiments and the figures mentioned therein are examples. These examples are illustrative in nature and are not intended to limit the embodiments of this disclosure or the use of such embodiments. Therefore, it should be understood that the embodiments of this disclosure are not limited in their application to the details of the construction and arrangement of the components set forth in the foregoing embodiments or shown in the figures.

[0047] The connecting lines shown in the figures included herein are intended to represent exemplary functional relationships and / or physical couplings between various elements. It should be noted that many alternative or additional functional relationships or physical connections may exist in one or more embodiments of this disclosure.

[0048] As used herein, the term "exemplary" means "serving as an example, instance, or illustration." Any embodiment described herein as exemplary should not necessarily be construed as preferred or advantageous over other embodiments. Furthermore, it is not intended to be bound by any express or implied theory presented in the foregoing technical field, background art, or specific embodiments. It should be understood that other terms and expressions used herein are for descriptive purposes and should not be considered limiting.

[0049] The terms “comprise,” “include,” “have,” and any variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. In this document, “A, B, and / or C” is defined as “A or B or C” or any combination of A, B, or C.

[0050] As used herein, unless expressly stated otherwise, “connection” means that one element is electrically or non-electrically joined directly to (or in direct communication with) another element, and not necessarily mechanically joined. Similarly, unless expressly stated otherwise, “coupling” means that one element is electrically or non-electrically joined directly or indirectly to (or in direct or indirect communication with) another element, and not necessarily mechanically joined. Therefore, although the schematic illustrations of the figures may depict exemplary arrangements of elements, additional intermediate elements, devices, features, or components may be present in one or more embodiments of the subjects depicted.

[0051] Unless explicitly indicated by the context, the terms "first," "second," and other such numerical terms referring to structures do not imply order or sequence. Therefore, the terms "first," "second," "third," "fourth," etc., in the embodiments and claims (if present) may be used to distinguish similar elements and are not necessarily used to describe a particular sequence or chronological order. It should be understood that the numerical terms used herein are interchangeable where appropriate, such that embodiments of the invention described herein can be operated, for example, with sequences other than those described herein or otherwise.

[0052] It should be understood that the steps of the various processes described herein are non-limiting examples of suitable processes according to embodiments and are for illustrative purposes. Systems and apparatuses according to embodiments herein may use any suitable process, including processes that omit the steps described above, processes that perform those steps in a different order, and similar processes, etc. It should also be understood that well-known process steps may be omitted for clarity.

[0053] As used herein, the terms “approximately,” “about,” “basically,” and “substantially” mean sufficient to achieve the purpose of the statement in a practical manner, and minor defects (if present) are not important to the purpose of the statement. In accordance with these principles, when used with reference to measurable quantities (including, but not limited to, dimensions), these terms mean that the quantity is equal to the stated value, subject to acceptable tolerances of any method or apparatus chosen for manufacturing the described structure or measuring the described quantity or dimension.

[0054] While at least one exemplary embodiment has been presented in the foregoing detailed descriptions, it should be understood that numerous variations exist. It should also be understood that the exemplary embodiments described herein are not intended to limit the scope, applicability, or configuration of the claimed subject matter in any way. In fact, the foregoing detailed descriptions will provide a convenient guide for those skilled in the art to implement one or more of the described embodiments. It should be understood that various changes can be made to the function and arrangement of the elements without departing from the scope defined by the claims, which includes known and foreseeable equivalents at the time of filing of this patent application.

Claims

1. A system, characterized in that, include: A circuit board that provides a first set of electrical interconnects; A first set of electronic devices and a second set of electronic devices are mechanically coupled to the circuit board, wherein the first set of electronic devices is configured to communicate with the second set of electronic devices via the first set of electrical interconnects. as well as An insert substrate, mechanically and electrically coupled to the circuit substrate, provides a second set of electrical interconnects configured to route radio frequency (RF) signals to the second set of electronic devices; The insert substrate is characterized by the loss tangent of the RF signal at a selected operating frequency of the second group of electronic devices; and The circuit board is characterized in that the second loss tangent of the RF signal at the selected operating frequency of the second group of electronic devices is greater than the first loss tangent.

2. The system according to claim 1, characterized in that, The second set of electronic devices includes two or more radar transceivers configured to operate coherently using a local oscillator (LO) signal distributed to each radar transceiver via the second set of electrical interconnects.

3. The system according to claim 2, characterized in that, The system further includes a set of transmitter structures housed within a carrier, the set of transmitter structures being configured to guide RF signals away from or toward the radar transceiver.

4. The system according to claim 3, characterized in that, The first set of devices is mounted on the top surface of the carrier, and the system further includes an antenna structure mechanically coupled to the bottom surface of the carrier and configured to couple RF signals to or from the radar transceiver via the transmitter structure.

5. The system according to claim 2, characterized in that, The selected operating frequency of the second group of electronic devices is the LO frequency of the local oscillator; and The second set of electrical interconnects forms a passive RF power divider, which is configured to receive the LO signal at the input port of the power divider at the LO frequency and distribute the LO signal to a set of output ports of the power divider.

6. The system according to claim 5, characterized in that, The insert substrate includes an amplifier configured to generate an amplified LO signal and couple the amplified LO signal to the radar transceiver via the passive RF power divider.

7. The system according to claim 5, characterized in that, The insert substrate is characterized by a loss tangent of less than 0.01 at frequencies greater than 10 GHz.

8. The system according to claim 5, characterized in that, The RF power divider and the insert substrate are jointly configured and arranged such that the corresponding phases of the LO signals measured at each output of the power divider are equal within a tolerance of less than five degrees.

9. The system according to claim 5, characterized in that, The RF power divider is a substrate-integrated waveguide (SIW) coupler.

10. The system according to claim 5, characterized in that, The RF power divider is a stripline power divider.

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