## 5 Conclusions  
A high-efficiency, wide-bandwidth empty patch antenna integrated into an ESIW has been proposed for space applications. It utilises an empty patch with a rod and is fed using an ESIW line to achieve a radiation efficiency of at least 90% at the operating frequency and a -10 dB impedance bandwidth of 19%. The proposed patch is the first floating patch held by a metallic rod and fed by an ESIW without supports or external elements that degrade the response. There is very little difference between the manufactured and simulated prototypes, showcasing the good and easy manufacturing method. In addition, yield and parametric analysis prove that the device is quite robust to manufacturing errors, while the most likely error sources have been traced and mitigated. Compared to other similar patches, it offers a superior compromise between bandwidth, directivity, and efficiency, with remarkable values in both bandwidth and efficiency. Additionally, it is easy to manufacture, small, and provides a robust patch placement, making it particularly suitable for applications requiring high efficiency and performance across a broad frequency range. This opens the possibility to develop high-performance array antennas fully integrated in ESIWs and with exceptional efficiency.  
All of these factors prove that floating patches fully integrated into SICs are very convenient for microwave satellite communications. This will allow the development of high-performance array antennas with low-loss ESIW feeding, enabling full communication systems integrated into SIC circuits, making them exceptional for the next satellite generation.  
Conceptualization, A.B., M.D.F. and A.A.; methodology, A.B., M.D.F. and A.A.; software, M.D.F. and D.H.T.; validation, A.B., M.D.F., D.H.T., I.G.C., D.H.-Z. and A.A.; formal analysis, A.B.; investigation, D.H.T. and A.A.; resources, A.B.; data curation, D.H.T. and D.H.-Z.; writing--original draft preparation, D.H.T.; writing--review and editing, A.B., M.D.F., D.H.T., I.G.C. and D.H.-Z.; visualization, D.H.T. and D.H.-Z.; supervision, A.B., M.D.F. and A.A.; project administration, A.B.; funding acquisition, A.B. All authors have read and agreed to the published version of the manuscript.  
This work was partially supported by the coordinated Research Project PID2022-136590 OB, Subproject C44, funded by MICIU/ AEI/10.13039/501100011033, Spanish Government, and by ERDF A way of making Europe, EU, and partially supported by the coordinated Research Project TED2021-129196B, Subproject C44, funded by MICIU/ AEI/10.13039/501100011033, Spanish Government, and by the European Union NextGenerationEU/PRTR. This work was developed thanks to the European social fund ESF+.  
Not applicable.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
Gamma research group.  
The authors declare no conflicts of interest.  
The following abbreviations are used in this manuscript:  
\begin{tabular}{l l} SIC & Substrate Integrated Circuit \\ ESIW & Empty Substrate Integrated Waveguide \\ BW\({}_{-104\text{B}}\) & Bandwidth at \(-10\) dB \\ \end{tabular}