Making roads safer with a novel antenna design for inter-vehicle communications
Novel antenna design that provides better range and gain than conventional antennas could be key to preventing accidents.
Daejeon, January 16, 2020
As cars evolve to become smart autonomous vehicles, researchers and engineers work hard to increase road safety. Reliable vehicle-to-vehicle communication is one of the ways this can be done, but current antennas suffer from intrinsic drawbacks that limit their range and efficiency. In a recent study published in the ETRI Journal, a novel antenna that outperforms existing ones was developed by a team from the Korea Advanced Institute of Technology (KAIST), with Professor Chul Soon Park at the helm.
“At present, many sensor technologies are used to enhance the safety of roads with autonomous vehicles, but vehicle-to-vehicle communication technologies are also needed. This is because sensors only work within their fields of view,” explains Prof. Park. Indeed, a wireless communication protocol designed specifically for vehicles, called Wireless Access in Vehicular Environments (WAVE), already exists. Based on it, safety-related applications for autonomous vehicles can be developed to avoid accidents and reduce traffic congestion. However, the antenna design currently used in the on-board units for WAVE has inherent flaws that limit its performance.
Ideally, the beam patterns radiating from antennas should accurately match their intended use. For instance, the pattern for a WAVE antenna placed on a car’s roof should be isotropic (equal in intensity) on the horizontal plane all around the car. No radiation lobes or beams should be emitted vertically or diagonally upwards or downwards because no cars would ever be located in those spaces and that energy would be wasted. in conventional WAVE antennas, a vertical row of equally spaced antenna micro-patches is placed on top of a non-conducting substrate, which separates them from ground (zero-voltage) patches. The functioning of these antennas is hampered by what is known as “surface waves” — when an antenna patch radiates electromagnetic waves, part of this radiation travels back through the substrate both up the antenna and down towards the metallic roof of the car. When these surface waves hit the car roof or when they reach the edges of the substrate, they radiate into the space around the car, interfering with the main radiation beams from the antenna patches.
Scientists from the Korea Advanced Institute of Science and Technology and the Electronics and Telecommunications Research Institute, led by Professor Chul Soon Park, identified this as a design issue. To fix the problem, they designed a novel antenna structure in which small metallic mushroom-like cells are arranged in a specific pattern in the inter-patch spaces. These metallic cells are connected to the ground plane, thereby preventing the formation of surface waves on the substrate. Through simulations and experimental analyses, the scientists determined the optimal sizes and arrangement of the cells to achieve the required isotropic pattern. Upon testing the novel antenna design, they found that it shows better range, gain and coverage around the car than conventional antennas.
“The improved performance of our antenna can increase the connectivity of vehicle-to-everything communications in WAVE systems,” remarks Prof Park. It can be applied to making roads with self-driving cars much safer. For example, if a car slips on ice on a curve, other nearby cars can be notified to prevent future accidents on that spot.
The proposed antenna is cheap and simple, which makes its implementation in current cars easier. Further refinements will hopefully allow this invention to replace the conventional monopole antenna, enabling safer and more convenient driving.
Reference
Name of author: Hongchan Kim1, KyuBong Yeon2, Wonjong Kim3, Chul Soon Park1
Affiliation:
1School of Electrical Engineering, Korea Advanced Institute of Technology
2ADAS center, Korea Automotive Technology Institute
3Seoul SW-SoC Convergence R&BD Center, Electronics and Telecommunications Research Institute
About Professor Chul Soon Park
Chul Soon Park received his PhD degree in Materials Science and Engineering from the Korea Advanced Institute of Science (KAIST) in 1985. From then, until 1999, he worked at the Electronics and Telecommunications Research Institute (ETRI). Since 1999, he has been with KAIST, where he is currently Professor at the Department of Electrical Engineering and Director of the Intelligent Radio Engineering Center. His research interests include reconfigurable RFIC and millimeter-wave ICs, among other things.
Media contact:
hchkim@tipa.re.kr
