# Quasi-Isotropic Hybrid Dielectric Resonator Antenna--Bow-Tie Patch with Harmonic Suppression
## 3 Fabrication and Measurement  
Figure 10 shows the fabricated shape and configuration of the proposed antenna, which consists of a DRA, a bow-tie patch, and a low-pass filter. The DRA is attached to the ground and the substrate's upper surface, then power is fed through a low-pass filter  
Figure 8: Simulated radiation pattern with and without filter: (**a**) 3.1, (**b**) 3.13, and (**c**) 3.15 GHz.  
Figure 9: The simulated electric field distribution of the proposed antenna: (**a**) xy, (**b**) yz, and (**c**) xz plane.  
located on the lower surface of the substrate. The bow-tie patch is applied with copper tape and attached to the DRA. A hole is drilled in the DRA, and a metal post is inserted to power the bow-tie and DRA simultaneously. It is electrically connected to the low-pass filter located on the lower surface of the substrate.  
Figure 11 is a graph comparing the measured and simulated S11 of the fabricated antenna. For the S11 measurement of the proposed antenna, the HP8510C network analyzer was used; the measured S11 band satisfying \(-\)10 dB or less was 3.10-3.28 GHz (5.64%) and the simulated S11 band was 3.09-3.3 GHz (6.25%). The simulated S11 and the measured S11 results agree. In addition, it was confirmed that the integrated filter sufficiently suppresses harmonics other than the operating band.  
Figure 12 shows the measurement environment of the anechoic far-field chamber to measure the radiation pattern of the manufactured antenna. The manufactured antenna is loaded on the jig, and paper tape is used to fix the antenna during the measurement process. The antenna fabricated through the feed cable is excited, and the radiation pattern is measured while the post and the jig are mechanically rotated. In the pattern measurement section, \(\varphi\) ranges from 0\({}^{\circ}\) to 360\({}^{\circ}\), \(\theta\) ranges from 0\({}^{\circ}\) to 180\({}^{\circ}\).  
Figure 10: Fabricated shape and configuration of the proposed antenna.  
Figure 11: Simulated and measured S11 of the proposed antenna.  
Figure 13 shows the radiation patterns of the xz, yz, and xy planes at 3.1, 3.13, and 3.15 GHz, respectively, in the anechoic far-field chamber. The post and jig's presence on the \(-\)z axis causes a slight difference in the shape of the measured and simulated radiation patterns of the back radiation of the proposed antenna. However, it was confirmed that a sufficiently uniform gain was secured to cover all directions in the measured and simulated radiation patterns.  
Figure 12: Photograph of the anechoic far-field chamber for measuring the radiation pattern of the proposed antenna.  
Figure 13: Comparison of simulated and measured radiation patterns of the proposed antenna: (**a**) 3.1, (**b**) 3.13, and (**c**) 3.15 GHz.  
Table 5 shows the simulated and measured gain difference. To remove the influence of post and jig on the \(-\)z axis on the radiation pattern, the range of the radiation pattern was set as \(0^{\circ}\leq\varphi\leq 360^{\circ}\) and \(0^{\circ}\leq\theta\leq 90^{\circ}\). In the case of the maximum gain, it was confirmed that the simulated and measured results had similar values, but in the case of the minimum gain, a difference of approximately 2 dB occurred. The reason is the influence of the unshielded feed cable and tools for measuring the radiation patterns. However, both results display a sufficiently uniform gain in the presented radiation section.  
Figure 14 shows the comparison between the measured and simulated maximum gain according to frequency. The measurement and simulation results agree, and harmonics are suppressed in the section other than the operating band. The simulated gain isolation between the operating band and the second and third harmonics are 11.20 and 14.69 dB, respectively, and the measured gain isolation is 10.10 and 18.94 dB, respectively. Therefore, it was confirmed that radiation by harmonics was sufficiently suppressed.