SWRA820B May   2024  – November 2024 IWRL6432AOP

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Increased Receiver Noise Figure
  6. 3Risk of Receiver ADC Saturation
  7. 4TX Backoff and RX Gain Recommendations
  8. 5Chirp Configuration Recommendations Using Sensing Estimator
  9. 6Summary
  10. 7References
  11. 8Revision History

1 Introduction

When determining overall system performance with FMCW radar sensors, many factors affect the range of detection. Range of detection is determined by chirp slope, IF bandwidth, and the signal-to-noise ratio (SNR) of the reflected energy from a detected object. The SNR in turn depends on EIRP (combination of TX power and TX antenna gain), EINF (combination of RX antenna gain and RX noise figure) and RCS of the target object. With the xWRL6432AOP device, there is limited isolation between transmit and receive antennas due to the close proximity of the antennas on the antenna-on-package (AOP) device.

This impacts the receiver performance in two ways:

  • Impact 1: Increased receiver noise figure
    • Due to the noise riding on the TX- RX coupled signal the noise figure is increased.
  • Impact 2: Risk of receiver ADC saturation
    • The TX - RX coupling causes a low frequency signal at the RX output which can be large enough to saturate the ADC if precautions are not taken.