JP5635259B2 - Dual-band antenna array and RF front end for automotive radar - Google Patents

Description

  This patent application is entitled “Three Dimensional Integrated Vehicle Radar and its Manufacturing Method” filed Apr. 4, 2008, assigned to the assignee and expressly incorporated herein by reference. Claimed priority based on US application Ser. No. 12 / 098,283, and is a partial continuation application thereof.

  The present invention relates to a low-cost three-dimensional integrated automobile radar and a manufacturing method thereof. More particularly, the present invention relates to a dual-band antenna array and RF front end for automotive radar, which combines a long-range narrowband radar and a short-range ultra-wideband radar.

  Automotive radar systems are currently installed in many luxury vehicles. Over the past few years, automotive radar systems have been used with intelligent cruise control systems to detect and adjust the speed of a vehicle to meet traffic conditions. Today, automotive radar systems are used with active safety devices to monitor the surroundings of a vehicle for collision avoidance. Current automotive radar systems are divided into long distance (for adaptive cruise control and collision warning) and short distance (pre-collision, collision mitigation, parking assistance, invisible location detection, etc.). Two or more radar systems, typically 15 × 15 × 15 cm in size, for example 24 GHz short range radar system and 77 GHz long range radar system, are used to provide long range and short range detection. The

  Conventional automotive radar systems have several drawbacks. For example, conventionally, since a plurality of radar systems are separately attached to a vehicle, a considerable space is required and wasteful. Each additional radar system increases the cost of mounting and assembly of each radar system. In order for each radar system to operate properly, the equipment placed on top of each radar system must be carefully selected so that the equipment is transparent to RF. The cost of multiple radar systems is further increased because multiple RF transparent areas are required at the front, side and rear of the vehicle. Thus, as the number of radar systems increases, mounting, assembly, installation and equipment costs increase.

The following patent documents 1 to 3 exist as documents showing the general level of the technology related to the present invention at the time of the present invention.

U.S. Pat. No. 7,187,334 U.S. Pat. No. 7,109,922 US Pat. No. 6,668,867

  Accordingly, there is a need in the art for a low cost three-dimensional integrated automotive radar having a dual band antenna array and an RF front end that combines long range narrowband radar and short range ultra wide area radar.

  The present invention forms a dual-band antenna array and an RF front end that couples long-range narrowband radar (eg, 77 GHz) and short-range ultra-wide area radar (eg, 24 GHz), and is a low-cost, compact 3- D-integrated automotive radar. This compact 3-D integrated automotive radar significantly reduces manufacturing, assembly and installation costs. In addition, the use of 3-DRF assembly techniques minimizes the number of connections and transitions required between the antenna and the chip, thus improving radar noise and sensitivity. Further, the compact 3-D integrated automotive radar reduces the space required to mount radar sensors on the vehicle (eg, front and rear bumpers), wiring, and RF transparent equipment at multiple locations on the vehicle.

  In one embodiment, an automotive radar includes a printed circuit board having a top surface and a bottom surface, a processor mounted on the bottom surface of the printed circuit board, a second liquid crystal polymer layer formed on the top surface of the printed circuit board, a second A second microstrip array printed on the liquid crystal polymer layer and having a patch, a first liquid crystal polymer layer formed on the second liquid crystal polymer layer, a patch printed on the first liquid crystal polymer layer and a perforated patch And a first microstrip array connected to the bottom surface of the second liquid crystal polymer layer and transmitting a first frequency signal to the first microstrip array and transmitting a second frequency signal to the second microstrip A transceiver module configured to transmit to the array.

  In another embodiment, an automotive radar includes a printed circuit board having a top surface, a bottom surface and a cavity, a bottom layer disposed on the top surface of the printed circuit board and having a plurality of patches, and connected to the plurality of patches and on the bottom layer. A lower microstrip feed, arranged in The automotive radar further includes an upper layer disposed on the lower layer and having a single patch with a plurality of holes to expose the plurality of patches, and connected to the patch and disposed on the upper layer. An upper microstrip feed and a first signal disposed in the printed circuit board cavity and having a first frequency to the upper microstrip feed and having a second frequency A transmission module configured to transmit the signal to the lower microstrip feed.

  The features, objects and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings.

1 is a perspective view of a low-cost, compact radar according to an embodiment of the present invention, which includes a dual-band array composed of at least two coupling layers disposed on a common ground plane (ground plane). A three-dimensional integrated structure is used. 1 is a top view of a low-cost, compact radar according to an embodiment of the present invention, the radar having a three-dimensional integration with a dual-band array composed of at least two coupling layers disposed on a common ground plane Use structure. 1 is a development view of a low-cost, compact radar according to an embodiment of the present invention, the radar having a three-dimensional integration having a dual-band array composed of at least two coupling layers disposed on a common ground plane. Use structure. 1 is a cross-sectional view of a radar 3-D integrated dual band RF front end according to one embodiment of the present invention, the radar being formed on a printed circuit board (PCB). FIG. 4 is a cross-sectional view of a radar 3-D integrated dual-band RF front end according to another embodiment of the present invention, in which the second layer is directly attached to the PCB and mounted T / R module Is attached to the bottom surface of the second layer by flip chip. 1 is a cross-sectional view of a via fence according to an embodiment of the present invention, which is used to provide separation between a first patch array and a second patch array. 1 is a top view of a via fence according to an embodiment of the present invention, which is used to provide separation between a first patch array and a second patch array. FIG. FIG. 4 is a cross-sectional view of a radar 3-D integrated dual-band RF front end according to another embodiment of the present invention, the radar having a 77 GHz aperture feed located on the underside of a 77 GHz patch array.

  Apparatus, systems, and methods that implement embodiments of various features of the invention are described below with reference to the drawings. The drawings and the associated description are provided to illustrate some embodiments of the invention and are not intended to limit the scope of the invention. In each drawing, reference numbers are re-used to indicate correspondence between referenced elements. For the purposes of this disclosure, the term “patch” is used synonymously with the term “antenna”.

  FIGS. 1, 2 and 3 are perspective, top and exploded views of a low cost compact radar 100, wherein the radar 100 is arranged on a common ground plane 120 in accordance with an embodiment of the present invention. A three-dimensional integrated structure having a dual band array 105 formed by the coupling layers 106 and 107 is used. The dual band array 105 includes a first layer 106 (for example, an uppermost layer or an upper layer) and a second layer 107 (for example, a lower layer). In one embodiment, the first layer 106 and the second layer 107 are bonded together and each have a thickness of about 4 mils (101, 6 μm). The first layer 106 and the second layer 107 may be liquid crystal polymer (LCP), low temperature co-sintered ceramic (LTCC), parylene N dielectric, polytetrafluoroethylene (PTFE) ceramic, PTFE glass fiber material, or multilayer structure. Can be formed by any other material capable of forming a metallized layer of a thin film (approximately 2-4 mils thick (50, 8-101, 6 μm)) that can be laminated. Radar 100 can be implemented using hardware, software, firmware, middleware, microcode, or any combination thereof. One or more elements can be repositioned and / or combined, and other radars can be used in place of the radar 100 while maintaining the spirit and scope of the present invention. Elements can be added to or removed from the radar 100 while maintaining the spirit and scope of the present invention.

  The first layer 106 has a series microstrip patch array 110 operating at 24 GHz. The patch array 110 includes one or more perforated patches 111 (ie, antennas) in which each hole or aperture 112 is an approximately 1.4 mm square aperture, which is a second 77 GHz patch 113 (i.e., antenna) located at or above layer 107 is exposed. The second layer 107 has a serial microstrip patch array 115 operating at 77 GHz. The 77 GHz series microstrip patch array 115 may be printed on the second layer 107. In one embodiment, each perforated patch 111 is about 3.6 mm square and each patch 113 is about 1.2 mm square. The patches 111 are connected to each other via a connector 114. The size of each opening 112 is optimized so as to have the least influence on the radiation efficiency of the patches 111 and 113.

In order to keep grating lobes eliminated and the side lobe to a low level, the first patch array 110 spacing between the second patch array 115 is a lambda _0/2. Here, λ ₀ is a free space wavelength of 24 GHz and 77 GHz, respectively. Based on the ratio between the two wavelengths (77 / 24≈3), four 77 GHz patches 113 are arranged within the outer boundary of one 24 GHz patch 111. Further, two 77 GHz patches 113 are arranged between two adjacent 24 GHz patches 111.

  FIG. 4 is a cross-sectional view of a 3-D integrated dual band RF front end of a radar 100 formed on a printed circuit board (PCB) 109 according to one embodiment of the invention. In one embodiment, a packaging layer 108 is formed on the PCB 109. The packaging layer 108 is formed of LCP and is used for mounting the T / R module 141. For example, the packaging layer 108 may have a cavity 140 that holds the T / R module 141. Further, the IF filter may be embedded in or formed on the packaging layer 108. In one embodiment, the T / R module 141 can be used at both frequencies or multiple frequencies.

The second layer 107 may be formed between the 77 GHz array 113 and the T / R module substrate 120. The array of second patches 113 is formed on or as part of the second layer 107. The microstrip feed 122 connects the second array of patches 113 to the T / R module 141. The microstrip feed 122 moves to the T / R module 141 via the second via 124. The first layer 106 may be formed on the microstrip feed 122 and / or the second layer 107. An array of first perforated patches 111 (eg, 24 GHz patches) may be formed on or as part of the first layer 106. The holes 112 on the first layer 106 allow relatively unobstructed radiation to pass from the second patch 113 (eg, 77 GHz patch) array. In one embodiment, each of the holes 112 are square (one) shaped openings (i.e., the lower portion of the circumference of the corner is smaller than the circumference of the upper corner, horn shape), which by the radiation of each patch 113 Improve efficiency. A microstrip feed 121 connects the array of first patches 111 to the T / R module 141. The microstrip feed 121 moves to the T / R module 141 via the first via 123 and may be formed on the first layer 106 or may be formed as part of the first layer 106. . The first layer 106 may include a 24 GHz series patch array 110 and a microstrip feed 121. The microstrip feed 121 and the microstrip feed 122 may include a network or line of feed connectors.

  The first layer 106 has one or more microstrip feeds 121 and the second layer 107 has one or more microstrip feeds 122. Microstrip feeds 121 and 122 are used as connections to first and second layers 106 and 107, respectively. In one embodiment, the patch arrays 110 and 115 comprise microstrip patch antennas.

  Multiple chips and / or components 160 (eg, two silicon-germanium (SIGe) BiCMOS chips) may be mounted on the bottom surface 119 of the PCB 109. The plurality of chips and / or components 160 may include one or more of the following: digital signal processor (DSP), digital clock, temperature controller, memory, microprocessor, dynamic link library, DC port, data Port, voltage controlled oscillator, PLL, etc. Multiple chips and / or components 160 may be connected to each other via connectors, traces or wires on a wireless link or PCB 109. Output signal 170 (ie, digital, DC, IF or RF signal) from T / R module 141 is directly connected to multiple chips and / or components 160 using through vias 165 (or connected wirelessly). You may do it.

  The T / R module 141 may be flip-chip bonded or attached on the bottom surface of the second layer 107. Flip chip transfer has very low parasitic inductance and low loss compared to conventional wire bonds. A plurality of heat dissipation vias 162 are directly connected to the T / R module 141 and allow (heat) to pass through the first and second layers 106 and 107. The plurality of heat dissipation vias 162 are used to remove heat from the T / R module 141 and transfer this heat to the heat removal area 163 located on the upper surface 116 of the first layer 106.

  FIG. 5 is a cross-sectional view of a 3-D integrated dual-band RF front end of a radar 200 in which a second layer 107 is directly attached to a PCB 109 according to another embodiment of the present invention. The packaged T / R module 141 is flip-chip mounted on the bottom surface 117 of the second layer 107. Output signals 170 (eg, digital, DC, IF or RF signals) from the mounted T / R module 141 are directly connected to multiple chips and / or components 160 using wire bonds 166 (or wireless connections). You may do it. In this embodiment, the T / R module 141 is prepackaged so that no additional LCP layer (eg, 108 in FIG. 4) is required.

  6A and 6B are a cross-sectional view and a top view of a via fence 190 (ie, a plurality of vias 195 arranged along a straight line). This via fence 190 is used for separation between the first patch array 110 and the second patch array 115 in accordance with the present invention. Via fence 190 ensures a high separation between the two frequencies. Vias 195 may be separated by a distance D, where D may vary to form a bandgap filter. In order to obtain a band gap effect, a periodic structure can be etched on the ground plane 120 in addition to the via 195. As a result of these bandgap effects, the 24 GHz signal on the 77 GHz transition line can be filtered out and vice versa.

  FIG. 7 is a cross-sectional view of a 3-D integrated dual-band RF front end of a radar 300 according to another embodiment of the present invention. The radar 300 has a 77 GHz aperture feed array 133 disposed below the 77 GHz patch array 115. In particular, a plurality of openings 133 are formed on the ground plane 120, and each opening 133 is formed below the 77 GHz patch 113. The ground plane 120 is formed or disposed on the bottom surface 117 of the second layer 107. In one embodiment, the 77 GHz aperture feed array 133 is replaced with the location of the 77 GHz microstrip feed array 122, which is attached or printed on the bottom surface of the third layer 103. The third layer 103 is similar to the first and second layers 106 and 107. Accordingly, the ground plane 120 separates the 24 GHz patch array 110 from the 77 GHz patch array 115, thereby minimizing or reducing leakage between the 24 GHz line and the 77 GHz line.

  The microstrip feed 121 is used to connect the first layer 106 to a first (eg 24 GHz) transmit / receive (T / R) module 141, and the microstrip feed 122 connects the second layer 107 to a second (eg 77 GHz) T / R module 142. The first T / R module 141 may be formed or disposed on the upper surface 116 of the first layer 106 and connected to the first microstrip feed 121. The second T / R module 142 may be formed or disposed on the bottom surface 104 of the third layer 103 and connected to the second microstrip 122. The first T / R module 141 is connected to a plurality of chips and / or components using vias 172, and the second T / R module 142 is connected to a plurality of chips and / or components 160 using wire bonds 166. It is connected to the. A heat dissipation strap 162 is used to remove heat from the first and second T / R modules 141, 142 and transport the heat to a waste heat area 163 located on the side of the radar 300.

  The patch array 110 is connected to the first T / R module 141 via, for example, a microstrip-based distribution network, and the patch array 115 is connected to the second T / R, for example, via a microstrip-based distribution network. Connected to module 142. The first and second T / R modules 141 and 142 may be T / R monolithic microwave integrated circuits (MMIC) or silicon-germanium (SiGe) BiCMOS chips, which are one or more of the following: Includes: T / R switch, low noise amplifier (LNA), variable gain amplifier (VGA), power amplifier (PA), phase shifter, mixer, intermediate frequency (IF) amplifier, and analog-digital (A / D) Converter. The first and second T / R modules 141 and 142 may be combined into one T / R module 141. The first T / R module 141 generates a first frequency signal (for example, a 24 GHz signal), and the second T / R module 142 generates a second frequency signal (for example, a 77 GHz signal). Also good. Alternatively, one or more chips or components 160, described below, can generate first and second frequency signals.

  Those skilled in the art can implement the various illustrative logic blocks, modules, and algorithm steps described in connection with the examples disclosed herein by electronic hardware, computer software, or combinations thereof. You will understand that. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above in terms of their functionality. . Whether such functions are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. A skilled engineer would be able to implement the functions described in various ways for each specific application. However, such implementation decisions should not be construed as departing from the scope of the disclosed apparatus and method.

  The various illustrative logic blocks, modules and circuits described in connection with the examples disclosed herein are general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gates. Realized and implemented by an array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination of these designed to perform the functions described herein . A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor can also be implemented by a combination of computing devices, eg, a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors associated with a DSP core, or any other such configuration. .

  The method or algorithm steps described in connection with the examples disclosed herein can be implemented directly by hardware, by software modules executed by a processor, or by a combination of the two. The software module may exist in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or a recording medium known in this field. A typical storage medium is coupled to the processor such that the processor can read information from, and write information to, the recording medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may be incorporated into an application specific integrated circuit (ASIC). The ASIC may be present in the wireless modem. In the alternative, the processor and the storage medium may reside as discrete components in a wireless modem.

  The above description of the disclosed examples is provided to enable any person skilled in the art to make and use the disclosed methods and apparatus. Various modifications to these examples will be readily apparent to those skilled in the art, and the principles disclosed herein may be applied to other examples without departing from the spirit and scope of the disclosed methods and apparatus. be able to. The described embodiments are illustrative in all respects and do not limit the invention, so the scope of the invention is indicated by the appended claims rather than the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be accepted as being within the scope.

105 Dual-band array 106 First layer 107 Second layer 110 First microstrip patch array 111 Perforated patch 112 Opening 113 Patch 115 Second microstrip patch array 120 Ground plane

Claims (19)

A printed circuit board having a top surface and a bottom surface;
A processor mounted on a bottom surface of the printed circuit board, wherein the processor is configured to generate a first frequency signal and a second frequency signal;
A second liquid crystal polymer layer formed on the top surface of the printed circuit board;
A second microstrip array having patches printed on the second liquid crystal polymer layer and operating at the second frequency;
A first liquid crystal polymer layer formed on the second liquid crystal polymer layer;
A first microstrip array having a perforated patch printed on the first liquid crystal polymer layer and operating at the first frequency, wherein the perforated patch is the first microstrip array A transmitter / receiver module connected to the bottom surface of the first microstrip array and the second liquid crystal polymer layer, having an opening formed to expose a patch, and connected to the processor; A transmit / receive module configured to transmit a signal of the first frequency to the first microstrip array and transmit a signal of the second frequency to the second microstrip array. , Automotive radar.   The automotive radar according to claim 1, wherein the patch is disposed directly below the perforated patch.   2. The automotive radar according to claim 1, wherein the transmission / reception module is flip-chip mounted on a bottom surface of the second liquid crystal polymer layer.   2. The automotive radar of claim 1, further comprising a plurality of heat exhaust vias directly connected to the transmit / receive module to remove heat from the transmit / receive module.   2. The automotive radar according to claim 1, wherein the first liquid crystal polymer layer is coupled to the second liquid crystal polymer layer.   The automotive radar according to claim 1, wherein the second frequency signal is transmitted from the patch through the perforated patch.   2. The radar for an automobile according to claim 1, wherein the transmission / reception module transmits a first transmission / reception module for transmitting the signal of the first frequency and a signal of the second frequency. And a second transmission / reception module.   The automotive radar according to claim 1, wherein the first frequency signal is about 24 GHz and the second frequency signal is about 77 GHz. 2. The automotive radar according to claim 1, wherein an opening of the perforated patch is formed in a horn shape and corresponds to a lower portion of the perforated patch in order to improve radiation efficiency through the opening of the perforated patch. to, the circumference of the lower portion of said horn, corresponds to the top of the perforated patch, less than the circumference of the upper portion of said horn, radar for automobiles.   The automotive radar of claim 1, wherein the transmit / receive module is selected from the group consisting of a SiGeBiCMOS chip and an all-silicon CMOS chip.   The automotive radar according to claim 1, further comprising a SiGeBiCMOS chip mounted on a bottom surface of the printed circuit board and including a voltage controlled oscillator, the automotive radar further comprising the second liquid crystal polymer layer and the printed circuit. An automotive radar comprising a ground plane located between a substrate and the ground plane separating noise generated by the SiGeBiCMOS chip. A printed circuit board having a top surface and a bottom surface;
A packaging layer having a cavity and disposed on an upper surface of the printed circuit board;
A lower layer having a plurality of patches disposed on the packaging layer and operating at a second frequency;
A lower microstrip feed connected to the plurality of patches and disposed on the lower layer;
An upper layer located on the lower layer and having a plurality of holes for exposing the plurality of patches and having a perforated patch operating at a first frequency;
An upper microstrip feed located in the upper layer and connected to the perforated patch, and further disposed in the cavity of the packaging layer, and further comprising a first signal having the first frequency An automotive radar comprising: a transmission module configured to transmit to a microstrip feed and to transmit a second signal having the second frequency to the lower microstrip feed.   13. The automotive radar according to claim 12, wherein the packaging layer, the lower layer, and the upper layer are each composed of a liquid crystal polymer, a low temperature co-sintered ceramic, a parylene N dielectric, a PTFE ceramic, and a PTFE glass fiber material. Automotive radar formed of a material selected from the group consisting of   13. The automotive radar according to claim 12, wherein the transmission module is selected from the group consisting of a SiGeBiCMOS chip and an all silicon CMOS chip.   13. The automotive radar according to claim 12, wherein the second signal is transmitted from the plurality of patches through the plurality of holes.   13. The automotive radar according to claim 12, wherein the transmission module includes a first transmission module for transmitting a first signal and a second transmission module for transmitting the second signal. Including automotive radar.   13. The automotive radar according to claim 12, wherein the first frequency is about 24 GHz and the second frequency is about 77 GHz.   13. The automotive radar according to claim 12, further comprising a plurality of exhaust heat vias directly connected to the transmission module to remove heat from the transmission module. A printed circuit board having a top surface, a bottom surface and a cavity;
A lower layer having a plurality of patches operating at a second frequency and disposed on the upper surface of the printed circuit board;
A lower microstrip feed connected to the plurality of patches and disposed on the lower layer;
An upper layer comprising a plurality of holes exposing the plurality of patches, having a perforated patch operating at a first frequency, and disposed on the lower layer;
An upper microstrip feed connected to the perforated patch and disposed on the upper layer; and
A first signal disposed within the cavity of the printed circuit board and having the first frequency is transmitted to the upper microstrip feed, and a second signal having the second frequency is transmitted to the lower microstrip feed. An automotive radar comprising: a transmission module configured to transmit to.

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