## 6 Conclusions  
The objective of the paper was to design an improved low-mass short backfire antenna for space and remote sensing applications. A combination of techniques was presented in this paper to improve the gain, bandwidth, and structural integrity of the waveguide-fed SBF antenna while reducing the total mass. Gain and bandwidth enhancement was achieved by employing the aperture flaring technique, which involved flaring the rim of the SBF antenna to an optimal angle of 20\({}^{\circ}\). After optimizing both the flaring angle and the rim height, the gain and bandwidth improved from 14.8 dBi to 17.2 dBi and from 26.4% to 54.4%, respectively, while having no significant effect on the cross-polarization ratio. The inductive iris was then used to further improve the impedance matching and the bandwidth of the antenna from 54.4% to 66.7%, while the gain and cross-polarization remained constant. Due to the low structural integrity of the foam lid that was used in the previous SBF antenna designs, a 3D-printed plastic lid that is stronger than the foam material was utilized. Both lids were then tested to compare their performance. We observed that the gain loss of the antenna with the plastic lid was a little higher than the gain loss of the antenna with the foam lid. This higher gain loss can be attributed to the higher dielectric constant of the plastic material. Finally, the antenna was fabricated with plastics by employing the additive manufacturing technique (3D printing) to significantly reduce the mass of the antenna. The measured results of the 3D-printed flared SBF antenna were in good agreement with the  
Figure 16: Measured radiation pattern results for the flared 3D-printed SBF antenna with the foam lid at (**a**) \(\varphi=0^{\circ}\), (**b**) \(\varphi=45^{\circ}\), and (**c**) \(\varphi=90^{\circ}\). The dashed lines represent the simulated results, while the solid lines represent the measured results. simulated results. However, some additional gain loss of about 0.4 dB was measured due to the increased surface impedance as a result of the additive manufacturing process. The flared SBF antenna's exceptional performance was demonstrated through comparison with other antenna designs (SBF and horn antennas) that operate within different microwave frequency ranges listed in Table 4. This table gives the frequency range of operation along with a comparison of the antenna designs' gain and impedance bandwidth. The weight and cross-polarization ratio of these designs were not disclosed, hence these characteristics were not included. The gain values of the flared antenna are similar to those of the antennas mentioned in [20; 22; 23]. However, the impedance bandwidth of the flared antenna is much wider than that of the above-mentioned antennas. This implies that the flared antenna can operate over a broader range of frequencies without significant changes in its performance, making it a more versatile option for similar applications. When compared to the antennas described in [24; 25; 26; 27], the flared SBF antenna performs better in terms of both gain and impedance bandwidth. The flared SBF was also compared to the standard gain C-band horn antenna [28], which is commonly used for the same applications as the SBF antenna. It can be seen from the table that the performance of the flared SBF antenna is superior to that of the standard gain horn antenna, having a higher gain and much wider impedance bandwidth. Therefore, the flared SBF antenna can be easily used as a better replacement for the horn antenna in satellite communication and remote sensing applications. The research presented in this paper showcases the potential of additive manufacturing for producing RF components, specifically antennas designed for space and remote sensing applications. This potential goes beyond reducing the mass, as demonstrated in the study, and includes the ability to manufacture complex designs that would have been difficult to achieve with traditional subtractive manufacturing processes.