Fig. 13 Simulated and measured E-plane and H-plane radiation pattern of the proposed antenna (a, b) 3.5 GHz, (c, d) 4.4 GHz, (e, f) 8.8 GHz, (g, h) 12.0 GHz.
Figure 13 (a), (c), (e), (g) shows the simulated (red solid line) and measured (red dotted line) normalized co-polar, simulated (black solid line) and measured (black dotted line) cross-polar E-plane (xy-plane) radiation pattern of the proposed antenna at 3.5, 4.4, 8.8, and 12 GHz respectively. Similarly figure 13 (b), (d), (f), (h) shows the simulated (black solid line) and measured (black dotted line) normalized co-polar, simulated (red solid line) and measured (red dotted line) cross-polar H-plane (xz-plane) radiation pattern of the proposed antenna at 3.5, 4.4, 8.8, and 12 GHz respectively From the simulated as well as measured co-polar H-plane radiation patterns of the proposed antenna at 3.5, 4.4, 8.8, and 12 GHz shown in figure 13 (b), (d), (f) and (h) it is clear that there is purely Omni-directional radiation pattern of co-polar H-plane at all the simulated and measured operating frequencies and it is highly consistent in all the operating frequencies. H-plane cross-polar radiation pattern at the operating frequencies of 3.5, 4.4, 8.8, and 12 GHz reveal that there is significant increase of the level of average simulated H-plane cross-polar radiation from -35 dB at 3.5 GHz to -20 dB at 12 GHz. This increase of the level of H-plane cross-polar radiation as the frequency increases is due to the destructive scattering of the radiation from the different edges of the constituent structures such as open-ended slit ring, SRR etc. On the other hand, the co-polar E-plane radiation patterns of the proposed antenna shown in figure 13 (a), (c), (e), (g) are directional along 00 and 1800, respectively. The co-polar E-plane radiation pattern at the operating frequencies of 3.5, 4.4, 8.8, and 12 GHz are roughly a dumbbell-shape or of the shape of English letter “8”. This shape of co-polar E-plane radiation pattern is highly consistent with all the operating frequencies of 3.5, 4.4, 8.8, and 12 GHz which shows that the proposed UWB notch antenna is well suitable for application in entire UWB system except in the operating band of WLAN. Regarding the simulated cross-polar radiation pattern of the E-plane radiation pattern, the level of average E-plane cross-polar radiation varies from -45 dB at 3.5 GHz to -30 dB at 12 GHz. The measured E-plane and H-plane radiation patterns of all the aspects such as co-polar and cross-polar radiation, the measured radiation patterns of E–plane and H-plane are in accordance with their simulated counterpart signifies accurate fabrication of the proposed antenna prototype.