The proposed technology includes 1) EHC-Frank coding to reduce interfer
ence in a multiuser millimeter-wave (mmWave) radar system and 2) 3-D Pi
llar-based shielding to reduce electromagnetic interference (EMI) in a mm
Wave radar system-in-package (SiP).
MmWave radars that can overcome severe weather conditions have been
gradually used in autonomous driving. When multiple mmWave vehicle ra
dars operate simultaneously, their radar signals inevitably interfere with e
ach other. This interference may adversely affect the radar functions and a

ccuracy, resulting in dangerous accidents. This proposed technology 1) us
es the polyphase Frank code featuring high auto-correlation and low cros
s-correlation and 2) reduces the cross-correlation through the Extended H
yperbolic Congruential (EHC) code with one-coincidence feature to constr
uct EHC-Frank codes as radar signals with high peak-to-sidelobe (PSLR) ra
tio. Therefore, a vehicle radar assigned with its own EHC-Frank code can si
gnificantly suppress the signals transmitted by other vehicle radars after p
erforming cross-correlation, effectively reducing the interference.
Due to the short-wavelength nature of mmWave frequency, mmWave acti
ve and passive components, such as radar transceivers and antennas, can
be integrated into a SiP through contemporary packaging technology. It c
an be envisioned that EMI among the components will affect the overall s
ystem performance. The proposed technology uses commercially availabl
e packaging technology, such as fan-out wafer-level packaging (FOWLP) o
r wire bonding, to create 3-D pillars that shield the components from EMI.
No additional process steps are required. Moreover, building a row of pilla
rs instead of a wall features better process uniformity and cost-effectivene
ss.
The above two techniques address reducing interference at the macroscal
e and microscale, respectively. They can be used in parallel without conflic
t to achieve a two-fold interference reduction for mmWav