Optimizing TI mmWave Radar Configurations for FCC
Publication
A new Application Brief (swra753?1?) describes how to optimize TI mmWave Radar configuration for FCC was published on 2022-Aug-17 on ti.com.
Background: FCC specifies two regulated bands for 60GHz. This leaves product designers with two options: to either operate * with a wider bandwidth or, * with a higher transmit power. More bandwidth increases range resolution, but higher transmit power increases the detection range. TI's suggestion for balancing these tradeoffs can be see in Figure 1.
Fig 1. from?1
A small summary of this publication follows, full application brief available on ti.com (swra753?1?)
Measuring Conducted and Radiated Power
In cases where it cannot be measured directly, conducted power can be computed by measuring the overall effective isotropic radiated power (EIRP), then subtracting the antenna gain.
Additionally, if using multiple transmit antennas at once for BPM-MIMO or beamsteering, there is a factor of 10log10(Nantennas).
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Option 1 : Higher Bandwidth and Lower Power
This provides the most precise range resolution (3.75 cm)
Those running a high-bandwidth/low-power configuration should pay special attention to your transmit power to ensure compliance with both the peak radiated and peak conducted FCC limits. In the high-bandwidth/low-power configuration, Pradiated must be less than +10 dBm and Pconducted must be less than -10 dBm. Although both the conducted and radiated limits must be observed, depending on the antenna gain value, only one of the two limits will become the limiting factor, and the other limit will be met automatically as a result.
Option 2: Lower Bandwidth and Higher Power
The low-bandwidth/high-power option enables detection at very long ranges. When designing a traffic monitoring sensor, using the maximum amount of transmit power allows you to detect cars further away. Similarly, if you want to detect the presence of people far away from the radar, increase your detection range by increasing the transmit power.
The main drawback of a low-bandwidth/high-power configuration is that range resolution is reduced.?With 500 MHz of bandwidth, the best range resolution that can be achieved is 30 cm.?This is entirely appropriate for detecting large targets, such as cars or people, but it will not be able to provide the same level of detail for detecting vital signals or distinguishing between closely spaced people that the higher bandwidth configuration can
References
1:?swra753?Application Brief - Optimizing TI mmWave Radar Configurations for FCC Certification
2:?FCC?RED?Compliance?spracp3c - FCC?RED?Compliance: https://www.ti.com/lit/an/spracp3c/spracp3c.pdf
This application note covers the requirements for compliance to regulatory standards for EU (RED) , and USA (FCC)
Part 15 subpart B, part 15 255 subpart C