Automotive 77 GHz Integrated Radar Module Assembly

As technology in vehicles continues to rely more on advanced driver-assistance systems (ADAS), many automotive suppliers are quickly developing improvements in applications such as automotive radar sensors that are part of total solutions which will meet stringent governmental safety requirements.  

Due to the width of available frequencies, many automotive radar technologies have moved from 24 GHz to 77 GHz. This higher frequency can achieve up to 20x better performance in range resolution and accuracy.

The range resolution of a 77 GHz system can be 40 mm versus 750 mm for 24 GHz radar, which allows for better detection of multiple objects that are close together. But an increase in frequency brings more EMI shielding and thermal interface material technology, so automotive suppliers look for a partner like Parker Chomerics, with our experienced application engineers to help develop new technology for these high performing applications. 

Parker Chomerics mechanical and application engineers, together with the customer’s engineering team, worked to design a model of the radar sensor housing, the RF shield and the radome to meet the customer’s stringent requirements. 

It was determined that the housing could be either molded from Parker Chomerics PREMIER electrically conductive plastic, or, as in this case, traditional thermoplastic with an added electrically conductive coating on the inside of the housing. 

The housing assembly design featured EMI shielding and thermal interface materials, an RF absorber, and a radome cover material suitable for laser welding.

During the design process, a finite element analysis (FEA) simulation was conducted to predict the reacting force of the EMI gasket around the 6-pin connector, the EMI gasket around the RF shield during installation into the housing, and the reacting force of the dispensable thermal interface material (TIM) during and after its installation.

The engineering team had to ensure that the targeted dispense location of the TIM would not cause deformation and/or damage to the PCB/IC during and after assembly. 

Parker Chomerics engineers developed an intergraded solution assembly consisting of a traditional thermoplastic housing, coated with Parker Chomerics CHO-SHIELD 2056 silver-plated copper EMI shielding paint. For effective heat dissipation away from the radar's PCB, THERM-A-GAP GEL 30 dispensable gel and THERM-A-GAP 580 gap filler pads were the best overall solution for the radar sensor assembly. Parker Chomerics CHOFORM 5528 form-in-place EMI shielding gasket provided effective attenuation around the connector pin.

The combination of these materials met the extensive testing and trials by both Parker Chomerics direct customer and their end customer’s requirements.