Two 24GHz automotive millimeter-wave radar chip solutions

Millimeter wave radar refers to radar that works in the millimeter wave band. The radar transmits radio waves to the surrounding area and measures and analyzes the reflected waves to calculate the distance, direction and size of obstacles. Typical applications include automotive anti-collision radar, helicopter control radar and precision tracking radar. The latest automotive millimeter wave radar can identify cars and pedestrians.

Automotive millimeter wave radar chip solution

The following introduces an automotive millimeter-wave radar solution based on the 24GHz integrated transceiver chip launched by UMS.

The 24GHz automotive millimeter-wave radar solution is mainly composed of a 24GHz RF transceiver chip, a control unit, and a CAN bus interface. The 24GHz RF transceiver chip realizes the generation, transmission, and reception of millimeter-wave signals. The control unit uses algorithms to realize the functions of ranging and speed measurement. The CAN bus interface is responsible for communicating with other parts of the car. The following is the basic block diagram of the 24GHz automotive millimeter-wave radar:

Figure 1: Basic block diagram of 24GHz automotive millimeter-wave radar

Based on this solution, the application of automotive anti-collision radars such as blind spot detection (BSD), lane change assist (LCA)/departure warning (LDW), and adaptive cruise control (ACC) can be realized. In addition, the application of ranging and speed radars in the fields of intelligent transportation speed and distance measurement, security, industrial control, etc. can also be realized.

The core device of this solution is the CHC2442, the only 24GHz integrated transceiver chip in the industry that uses GaAs technology, launched by UMS. The following are the main features of this device:

• Transmit power 13.5dBm

• Transmitter gain control range 12dB

• Receive gain 37dB

• Receive gain control range 24dB

• Noise figure 11dB (IF greater than 100KHz, RF gain maximum)

• Input 1dB compression point -16dBm

• VCO phase noise -90dBc/Hz@100KHz

• Temperature range -40℃ to 125℃

• Operating voltage 3.3V

• Package QFN4*5, meets RoHS standards

The 24GHz radar transceiver chip launched by UMS has become the best choice for 24GHz automotive millimeter-wave radar solutions with its automotive-grade operating temperature range, higher transmission power, and excellent VCO output phase noise.

24G Microwave Frequency VCO Solution

For 24GHz automotive millimeter wave radar systems, UMS has launched the CHV2421-QDG voltage-controlled oscillator (VCO) product for discrete systems. The device is a GaAs InGaP heterojunction bipolar transistor (HBT) MMIC VCO. The CHV2421-QDG integrates a resonator, a negative resistance device, a varactor diode, and a pre-divider.

The following is the functional block diagram of CHV2421-QDG. It can be seen from the figure that the VCO can generate two-way frequency division output up to 24GHz microwave frequency with a maximum of 15dBm.

Figure 1: CHV2421 functional block diagram

Product features of CHV2421:

• Frequency range 24-24.5GHz

• Typical output power 15dBm

• Output dynamic range 13dB

• Phase noise -90dBc/Hz

• Non-resonant emission clutter suppression 80dBc

• Pre-scaling transmit clutter suppression 55dBc

• Working voltage 5V

• Operating temperature -40℃~105℃

• Tuning voltage 0.5-5.5V

• Pre-scaling output power 0dBm

• 24L-QFN package lead-free soldering

• Meets MSL1 standards