# Design of Triple-Band (DSRC, 5G, 6G) Antenna for Autonomous Vehicle Telematics
## 3 Results  
### Eight-by-eight 6G Patch Array  
Based on the discussion in [14], it was determined that the Rogers 5880 substrate would be suitable for 6G frequencies, allowing all three layers of the stacked patch antenna to utilize the same substrate. However, the simulation indicates that the substrate must be about 0.051 mm thick to enable resonance at 6G frequencies.  
A single 6G patch antenna was designed to operate at 150 GHz, given the substrate's dielectric parameters. Following the topology described in [15], the width and length are equal at 0.33\(\lambda_{0}\), where \(\lambda_{0}\) is the wavelength at 150 GHz. Eight of these patches are cascaded with 0.33\(\lambda_{0}\) spacing and connected using a series-fed technique to form a one-by-eight array. To improve the impedance matching of a 50 \(\Omega\) input at 150 GHz, the eighth element of the one-by-eight array features a notch cut for an inset feed, as shown in Figure 3.  
Finally, one-by-eight arrays are cascaded with 0.17\(\lambda_{0}\) spacing to form the eight-by-eight array, as shown in Figure 4. This spacing was found to be the best to preserve the performance of the one-by-eight array.  
Figure 5 shows the 5-parameter and the realized gain at the boresight (\(\theta\), \(\varphi=0\)) of a single patch element, the one-by-eight array with and without the inset feed, the one-by-ten array with the inset feed, the four-by-eight array with the inset feed, and the eight-by-eight array. As the element increases from 1 to 8, the \(-10\) dB impedance bandwidth changes from a single resonant frequency range of 144.4-153 GHz (bandwidth of 8.6 GHz) to a multiple resonant frequency range between 134.8 and 158 GHz (bandwidth of 7.1 GHz). Compared to the one-by-eight array without a notch, the one-by-eight array with a notch tunes the resonance closer to the desired frequency, improves the depth of the second resonance, and increases the realized gain between 136 and 145 GHz, and 149 and 158 GHz. As the number of series elements increases from eight to ten, the resonant frequency ranges below the frequency of 147.5 GHz shift from left to right, while the resonant frequency at 148.  
frequency ranges decrease as the number of series elements increases. Due to the higher number of series elements for the one-by-ten array, a higher realized gain is observed compared to the one-by-eight array. Thus, the desired resonance frequency ranges and realized gain are achievable by manipulating the number of series elements. Eight series elements are arbitrarily chosen to show the effectiveness of the series-fed antenna array with other shared patch antennas.  
Lastly, as the number of parallel elements increases from one to eight, the resonant frequency ranges stay the same. As expected, a higher realized gain at the boresight is observed when the number of parallel elements increases. As Figure 5b shows, a high peak realized gain of 22.5 dBi is achievable at a boresight for the eight-by-eight series-fed antenna array. Eight parallel elements were chosen over the others because they are the maximum parallel elements that do not interfere with port I (5G) and provide the highest realized gain at the boresight.  
Figure 4: Eight-by-eight array.  
Figure 5: (**a**) S-parameter and (**b**) realized gain at boresight of a single patch element, the one-by-eight array, the one-by-eight array with the inset feed, and the final eight-by-eight array.