# Fully Metallic Additively Manufactured Monopulse Horn Array Antenna in Ka-Band
## 6 Conclusions  
In this work, a fully metallic horn array antenna with a difference pattern was designed and validated for operation in the K\({}_{\text{a}}\)-band, showcasing the potential of additive manufacturing (AM), specifically Laser Powder-Bed Fusion (LPBF), in producing high-precision, monolithic microwave components. The monolithic nature of the design allows for the integration of \(H\)-plane power dividers and complex \(90^{\circ}\) twist sections, which are otherwise challenging to manufacture with conventional methods. This approach minimizes alignment errors and leakage, yielding robust and compact structures that are well suited for high-performance mm-Wave applications. The prototype, additively manufactured and measured in both a far-field spherical range and planar near-field scanner, demonstrated stable performance across the operating bandwidth, achieving a \(-48.4\) dB null at \(33\) GHz in the difference pattern, with minimal frequency squinting.  
Overall, this study illustrates how AM not only addresses longstanding manufacturing limitations in high-frequency antenna designs but also opens new pathways for innovation in antenna systems with complex geometries and modular configurations. This work shows how LPBF allows not only the design but also the fabrication of antenna geometries that, until now, could not be realized due to the limitations of conventional manufacturing processes. In particular, it presents a design that integrates a \(16\times 16\)-element array with a feeding network containing complex elements, such as \(90\)-degree twisted sections. Additionally, a difference diagram is presented, which is very sensitive to design and manufacturing errors, as the array elements must be fed properly, not only in amplitude but also in achieving out-of-phase feeding, which is highly sensitive. Therefore, this work not only presents the design of an RF component but also addresses the design and testing of a monolithic device with high-sensitivity performance, presenting a system-level design. The successful application of LPBF in this project affirms AM's suitability for developing scalable difference pattern arrays and modular arrays optimized for mm-Wave applications, underscoring its significance in advancing the next generation of high-frequency antenna systems.  
Conceptualization, M.A. and A.F.V.; Analysis and Design, J.R.-F. and A.F.V.; Simulation Analysis, J.R.-F., A.F.V., M.R.P. and M.A.; Manufacturing, J.R.-F.; Measurements, M.R.P.; Draft Preparation, J.R.-F.; Writing-Review, A.F.V., M.R.P. and M.A.; Supervision, M.R.P. and M.A.; Funding Acquisition, M.A. All authors have read and agreed to the published version of the manuscript.  
This work was supported in part by MCIN/AEI/10.13039/501100011033 under grants PID2020-114172 RB-C21, PID20203-146246 OB-C32, and TED2021-130650B-C22, cofunded by the EU's (European Union) \"NextGenerationEU\"/PRTR and by the Spanish Ministry of Universities and European Union (NextGenerationEU fund) under grant MU-21-UP2021-0307189562J].  
Not applicable.  
The raw data supporting the conclusions of this article will be made available by the authors on request.  
Author [PERSON] was employed by the company Northern Waves AB. The remaining authors declare that the re-search was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.