In this paper, a performance study is conducted for a automotive MIMO RADAR antenna mounted behind a painted bumper. Initially, a 2Tx-4Rx MIMO RADAR antenna is designed and placed behind a simplified curved bumper. The individual Tx/Rx antenna is a seven-element series fed modified binomial array. Next, two layers of paint (primer coat and base coat) materials are applied on the bumper and performance of the antenna-painted bumper integrated system is studied using bi-directional loss and antenna array ambiguity function models. The proposed study provides a quantitative analysis into the MIMO RADAR performance matrics like bi-directiola loss, field-of-view and ambiguity in the direction-of-arrival estimation, caused by the real-time antenna-bumper interactions. 

Effect of Painted Bumper on Automotive MIMO RADAR Performance Study Using Bi-directional Loss and Antenna Array Ambiguity Function

In this paper, we study the integration effects of a 2D MIMO RADAR antenna for automotive applications, placed behind a painted bumper. First, a 3Tx-4Rx 2D-MIMO RADAR antenna system is designed, where the individual Tx/Rx antenna is a seven-element series-fed modified binomial array configuration having side-lobe level less than 16 dB and 80° azimuth field-of-view (FoV). Then the 2D MIMO RADAR antenna is placed behind a simplified curved bumper having two paint layers, and the antenna-painted bumper integration effects are studied via the S-parameter response and antenna array ambiguity function (AAAF) model. Both the AAAF and S-parameter analysis provide key insights into the comparative performance of 1D and 2D MIMO RADARs integrated with bumpers, which can help determine possible corrective measures in real-time applications. 

Antenna Array Ambiguity Function Based Study of Integration Effect on a 2D Automotive MIMO RADAR Antenna Placed Behind a Painted Bumper

This paper studies the theory of interference of reflected light to provide the equation for the optimum thickness of the bumper and the optimum distance between the radar and the bumper. The simulations are carried out at 77 GHz using a two-element microstrip array antenna which is placed behind the bumper made of materials Polycarbonate and Acrylonitrile-Butadiene-Styrene. Bidirectional losses and bandwidth are measured at normal incidence. The results for optimum separation between the radar antenna and the bumper have also been verified using a one-element array microstrip antenna operating at 24 GHz with a FR4 material bumper. It has been observed that for a small variation in thickness and separation between bumper and antenna, the losses change drastically. Losses increase sinusoidally with increase in the thickness and separation, but with the right selection of bumper thickness and separation from the antenna, the losses can be minimized. 

Study of the Bumper Thickness and its Placement for Automotive Radar Applications

In this paper, we propose a mathematical model to compute the bi-directional loss of an automotive radar in the presence of a bumper with multi-layered paint. The proposed model uses a physical optics (PO) based approximation for the reflective and dielectric losses. The model takes into account the shape of the bumper and compares it with a proprietary algorithm. The model is applied on a six-element microstrip array antenna placed behind a curved bumper, with and without the presence of multiple paint layers. The bidirectional loss, in the broad-side direction, as obtained from the model is 4.6 dB due to the presence of the bumper with a single paint layer and 8.8 dB when the number of paint layers is five.

Sajitha Vr

Papers

Performance Evaluation of Automotive Radar in The Presence of Bumper with Multiple Paint Layers Using Bidirectional Loss Model