The 122 GHz radar frontend TRX_120_001 or TRX_120_002 from Silicon Radar are analogue frontends which means that only the RF circuitry including the antennas is included in the QFN package. The baseband circuitry (filter, amplifier, AD converter) and the phase-locked-loop (PLL) for controlling the voltage controlled oscillator (VCO) are realized with discrete parts on the PCB. This yields in a high flexibility which makes adjustments to your application easily possible. The main drawback are the higher cost compared to even more integrated transceivers. An addiotional benefit of the high operating frequency is the beam focussing capability. The half-power-beamwidth (HPBW) by using a dielectric lens is halfed compared to 60 GHz system using the same lens dimensions.
The AD conversion and the control of other discrete parts (PLL, VGAs, filters, etc.) on this module is performed by a STM32L4 Cortex-M4 microcontroller. The standard firmware calculates the 3 dominant targets sorted by their amplitude value. The interface for transferring the targets is UART or I2C which is also used for controlling the module. Additionally, the raw ADC data could be transferred via SPI.
The basic operation overview is given in the following table:
| Parameter | Value |
| Frequency range | 119.3 -125.8 GHz (6.5 GHz) |
| ISM band | 122-123 GHz |
| Radar operation | FMCW and CW |
| Baseband high pass filter cutoff | variable (down to 0 for pure CW measurements) |
| ADC | 12 bit I and Q data |
| Baseband amplification (VGA) | variable baseband amplification possible |
| Power supply | 3.3 V |
| Current consumption | 500 mA peak |
| RAPID v3 platform | yes |
