TIDUFB9 April   2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Reference Design Features
      2. 2.2.2 Switch Settings
    3. 2.3 Highlighted Products
      1. 2.3.1 IWRL6432W
      2. 2.3.2 Crystal
      3. 2.3.3 TPS6285020M – 1.8V DC/DC Regulator
      4. 2.3.4 QSPI Flash Memory
  9. 3System Design Theory
    1. 3.1 Antenna
      1. 3.1.1 Range and Phase Compensation
      2. 3.1.2 Chirp Configuration
    2. 3.2 PCB
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
      1. 4.1.1 Reference Design
      2. 4.1.2 Small Form-Factor Reference Design
    2. 4.2 Software Requirements
    3. 4.3 Test Setup
    4. 4.4 Test Results
      1. 4.4.1 Human Detection at 15 Meters in Boresight
      2. 4.4.2 Antenna Radiation Plots
      3. 4.4.3 Angle Estimation Accuracy
  11. 5Design and Documentation Support
    1. 5.1 Design Files
      1. 5.1.1 Schematics
      2. 5.1.2 BOM
    2. 5.2 Tools and Software
    3. 5.3 Documentation Support
    4. 5.4 Support Resources
    5. 5.5 Trademarks
  12. 6About the Authors

3.1 Antenna

The reference design uses a single-element patch antenna for the three receiver and two transmitter antennas. The reference design has one TX antenna placed λ/2 below the other TX antenna in the elevation plane and 2 × λ/2 apart in the azimuth plane. All the RX antennas are kept in the same plane with λ/2 distance between RX1 and RX2 and RX2 and RX3.


TIDEP-01040 Virtual Antenna Array

Figure 3-1 Virtual Antenna Array

To save the overall space, the FR4-based antenna is located on the opposite side (backside) of the PCB from the IWRL6432W chip

The RX antennas are upside down compared to the TX antennas. Therefore, the virtual antenna array is also turned upside down after deriving the location of the virtual antennas in the given position.

Corresponding antenna geometry CLI command is:

antGeometryCfg 1 2 1 1 1 0 0 4 0 3 0 2 2.5 2.5

Note:
  1. This command line is necessary to add within any configuration, before sending the same to device, otherwise the angle of arrival calculated by the processing chain can be erroneous.
  2. See the MMWAVE-L-SDK documentation (tuning guide) for more details about this CLI command.

Figure 3-2 depicts the antenna gain plot for different frequencies across azimuth and elevation angles.


TIDEP-01040 Antenna Gain Plot

Figure 3-2 Antenna Gain Plot