# Integrated Module Antenna for Automotive UWB Application
## 2 Proposed Antenna Design
### Vehicle Model Simulation  
The measurements of the radiation pattern of the antenna mounted on the actual vehicle were replaced by a simulation, due to facility limitations and time difficulties. For the simulation, the SUV cad of the Hum3D was used as the vehicle model [21]. The simulation model of the vehicle had the same dimensions as that of the actual vehicle. For localization, the vehicle model was separated into front and rear parts. For simulation of the front part, the antenna modules with case was mounted under the headlamp in the engine room. In addition, the antenna was also mounted on the corner of the rear bumper for rear part simulation. The components of the vehicle model for the front part included a simplified engine room, battery, wheel with suspension head, front bumper, fender, and dashboard, as shown in Figure 15. The rear part of the vehicle model simulation consists of the rear bumper, wheel, fender, tail gate, and rear windshield, as shown in Figure 16. For the rear passenger detection sensor, the antenna module with case was mounted on the upper ceiling of the rear headrest in the vehicle. The components of the vehicle model for the rear passenger detection sensor included rear seats, interior frame, top ceiling with roof, trunk space, and rear bumper, as shown in Figure 17. The simulation was conducted with CST Studio Suite Full EM simulation software [19]. The radiation patterns of the monopole and patch array with actual mounting on the vehicle model are shown in Table 6.  
Figure 15: Simulation structure of the front part for localization antenna with vehicle model.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Monopole (6.5 GHz)** & **Monopole (8.0 GHz)** & **Patch Array (8.0 GHz)** \\ \hline \hline
**Algorithm** & **The measurement of return loss is conducted by using Agilent’s MS4644B Vector Network Analyzer. The measured return loss shows that the bandwidth of the monopole and patch array are 6.27\(\sim\)8.21 GHz and 6.85\(\sim\)8.61 GHz. The radiation pattern is measured in the anechoic chamber. The measured results of the beamwidth of the monopole in the yz-plane at 6.5 GHz are 172\({}^{\circ}\), and 117\({}^{\circ}\) at 8.0 GHz. The patch array has 5.22 dBi gain and 90.9\({}^{\circ}\) beamwidth in the xz-plane. The measured results of the proposed antenna are well agreed with the simulations.  
\end{table}
Table 5: Radiation pattern of the proposed antenna with case.  
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Figure 16: Simulation structure of the rear part for localization antenna with vehicle model.  
Figure 17: Simulation structure for rear passenger detection sensor with vehicle model.  
\begin{table}
\begin{tabular}{c c c} \hline \hline  & **Monopole (6.5 GHz)—Rear Part** & \\ \hline Left side & Right side \\ \hline \hline \end{tabular}
\end{table}
Table 6: _Cont._The radiation patterns of the monopole with the vehicle model show that sufficient coverage for UWB localization in the horizontal plane. Furthermore, the patch array shows the appropriate radiation pattern for the rear passenger detection sensor in the vehicle.