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AWR1642: Antenna design for Boost and TIDA-01570

ej99
Intellectual 640 points
Part Number: AWR1642
Other Parts Discussed in Thread: , TIDA-01570

I'm in the process of creating a custom PCB for the AWR1642. I'm referencing the AWR1642boost EVM as well as TIDA-01570 (Automotive 77GHz Radar Module Reference Design).

I noticed that both boards seem to use the same footprint for the patch antennas and feeds, i.e. the dimensions of the patches etc. are identical. However, the stackups for these boards seem to be different. The boost board uses Rodgers 4835, with a dielectric constant of 3.48. For the automotive board, there seems to be a discrepancy in the documentation (I'm looking at this document, p.18). It says "ceramic material from Rogers," but then in the table it lists 370HR (dielectric constant of 4.2), which is not from Rodgers. A change in dielectric constant would require a change in the antenna dimensions, so it seems like one of these boards is probably not optimally designed.

So my first question is, what is the actual dielectric material used for the automotive board?

More importantly, what material is recommended for this antenna design?

I'd like to make sure I'm using the right material on my board to maximize the antenna performance.

  • 0
    TI__Guru*** 147964 points
    Hi,

    There may be differences in the material used due to thelack of availability of the Rodgers 4835.

    Have you looked into availability of the materials

    thank you
    cesar
  • 0 in reply to Cesar
    Intellectual 640 points

    I haven't looked at availability of materials yet. At this point, I'd like to find out what material or dielectric constant the EVM antenna design was optimized for. Once I know that, then I can get a sense for what material I should ideally use and what trade-offs I'd make by using a different material.

  • 0 in reply to ej99
    Intellectual 640 points
    Looking at the Altium project file provided for TIDA-01570, the stackup has RO4835 LowPro between layer 1/2. I'm fairly sure now that the documentation referring to 370HR was simply incorrect, and that the antenna was designed for RO4835 LowPro.