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EP-3734322-B1 - RADAR UNIT WITH THERMAL TRANSFER VIA RADOME

EP3734322B1EP 3734322 B1EP3734322 B1EP 3734322B1EP-3734322-B1

Inventors

  • BEER, ROBERT C.
  • Carrell, Matthew S.
  • ROSSITER, RYAN K.

Dates

Publication Date
20260506
Application Date
20200331

Claims (12)

  1. A radar unit (14) comprising: a printed circuit board - PCB- (34) supporting an integrated circuit - IC - chip (40); and a radome (42) arranged over the IC chip (40), characterized in that the radar unit (14) further comprises a metallic spring (52) engaging the IC chip (40) and the radome (42), the spring (52) configured to transfer thermal energy between the IC chip (40) and the radome (42), wherein an electromagnetic interference - EMI-shield (68) is mounted to the PCB (34) about the IC chip (40) and electrically connected to a ground, and the spring (52) engages the EMI shield (68).
  2. The radar unit (14) of claim 1, wherein the IC chip (40) is a monolithic microwave integrated circuit - MMIC.
  3. The radar unit (14) of claim 1, wherein the radome (42) is constructed from a plastic material, and the spring (52) is constructed from a corrugated metallic material having flexible undulations (60, 62).
  4. The radar unit (14) of claim 1, wherein the radome (42) includes a metallic heat transfer bar (50), the spring (52) engaging the heat transfer bar (50).
  5. The radar unit (14) of claim 4, wherein the heat transfer bar (50) is provided by a metallic plating (58) deposited onto the plastic material.
  6. The radar unit (14) of claim 4, wherein the radome (42) includes a slot (49) that receives the heat transfer bar (50).
  7. The radar unit (14) of claim 6, wherein the heat transfer bar (150) includes a notch (64), and the spring (52) has a tab (66) that is received in the slot (49) and within the notch (64).
  8. The radar unit (14) of claim 1, comprising a plastic housing arranged about the PCB (34), and the radome (42) is provided by the plastic housing.
  9. The radar unit (14) of claim 8, wherein the housing (28) includes cooling fins (31).
  10. The radar unit (14) of claim 1, comprising a metallic housing arranged about the PCB (34), and the housing includes an aperture, and the radome (42) is overmolded within the aperture.
  11. The radar unit (14) of claim 1, wherein the PCB (34) includes a row of IC chips (40), and a common spring engages each of the IC chips (40) within the row.
  12. The radar unit (14) of claim 1, further comprising: a heat transfer stack (44) for transferring thermal energy between the IC chip (40) and the radome (42), the heat transfer stack (44) comprising a heat spreader (46) engaging the radome (42) and the IC chip (40), wherein the IC chip (40) is a monolithic microwave integrated circuit - MMIC - , the radome (242) is constructed from a plastic material, and the heat transfer stack (44) includes the spring (52) which is constructed from a corrugated metallic material.

Description

FIELD OF INVENTION The disclosure relates to radar unit with a radome and one or more integrated circuit (IC) chips. BACKGROUND Radar units are increasing used in vehicle and other applications to determine the location and proximity of objects to the vehicle. One typical radar unit includes one or more circuit boards arranged in a housing that has a radome. One or more IC chips are provided on the circuit board that is adjacent to the radome. The chips send waves through the radome and receive the waves reflected off of objects to determine the location and proximity of the objects to the chip, and thus, the vehicle. The development of one type of radar unit, such as an automotive long-range radar product, has resulted in the placement of radar monolithic microwave integrated circuits (MMIC) on a side the circuit board facing the radome. MMICs may generate a significant amount of heat, which must be transferred to the surrounding environment to ensure desired operation of the radar unit's electronics. A radar unit in accordance with the preamble of claim 1 is know from EP 3 070 784 A1. EP 2 538 106 A2 describes a spring suitable for electrically coupling electrical contact surfaces when the spring is in contact therebetween. CN 107 889 431 A describes a heat dissipation structure of a millimeter wave radar, wherein the heat dissipation structure comprises a rear cover, a radar mask, a printed circuit board assembly and a decorating part, and wherein the radar mask is matched with the rear cover to form a sealing structure. This document also foresees in the use of an elastic heat conductive material. SUMMARY In one exemplary embodiment, a radar unit includes a printed circuit board (PCB) supporting an integrated circuit (IC) chip. A radome is arranged over the IC chip. A spring engages the IC chip and the radome. The spring is configured to transfer thermal energy between the IC chip and the radome. An electromagnetic interference (EMI) shield is mounted to the PCB about the IC chip. The spring engages the EMI shield. In a further embodiment of the above, the IC chip is a monolithic microwave integrated circuit (MMIC). In a further embodiment of any of the above, the radome is constructed from a plastic material. The spring is constructed from a corrugated metallic material having flexible undulations. In a further embodiment of any of the above, the radome includes a metallic heat transfer bar. The spring engages the heat transfer bar. In a further embodiment of any of the above, the heat transfer bar is provided by a metallic plating that is deposited onto the plastic material. In a further embodiment of any of the above, the radome includes a slot that receives the heat transfer bar. In a further embodiment of any of the above, the heat transfer bar includes a notch. The spring has a tab that is received in the slot and within the notch. In a further embodiment of any of the above, the radar unit includes a plastic housing arranged about the PCB. The radome is provided by the plastic housing. In a further embodiment of any of the above, the housing includes cooling fins. In a further embodiment of any of the above, the radar unit includes a metallic housing arranged about the PCB. The housing includes an aperture. The radome is overmolded within the aperture. In a further embodiment of any of the above, the PCB includes a row of IC chips. A common spring engages each of the IC chips within the row. As a non-claimed possibility, a method of manufacturing a radar unit includes the steps of securing a printed circuit board (PCB) that has an integrated circuit (IC) chip to a housing portion, mounting a spring to a radome, and securing the radome relative to the housing portion to engage the IC chip with the spring. In a further unclaimed embodiment of any of the above, the radome includes a heat transfer bar. The mounting step includes engaging the spring with the heat transfer bar. In a further unclaimed embodiment of any of the above, the method includes the step of depositing the heat transfer bar onto a radome substrate. In a further unclaimed embodiment of any of the above, the method includes the step of inserting the heat transfer bar into a slot in a radome substrate. In a further unclaimed embodiment of any of the above, the method includes the step of inserting a tab of the spring into a notch in the heat transfer bar. In a further embodiment of any of the above device embodiments, the radar unit further includes a heat transfer stack for transferring thermal energy between the IC chip and the radome. The heat transfer stack comprises a heat spreader that engages the radome and the IC chip. The IC chip is a monolithic microwave integrated circuit (MMIC). The radome is constructed from a plastic material. The heat transfer stack comprises a spring constructed from a corrugated metallic material. As seen from the above, the radar unit includes a shielding device for minimizing electromagnetic interf