A 1-to-8 Fully Modular Stacked SIW Antenna Array for Millimeter-Wave Applications

This paper presents a vertically stacked SIW antenna array that enables different array configurations with the minimum number of SIW layers. This achievement lies in the modular feature offered by the proposed design. Specifically, 4 distinct array configurations can be produced with only 3 different design of SIW layers. Depending on the number of SIW layers employed in the stacked antenna, the directivity in the E-plane of radiation is modified. To obtain an equal and in-phase power distribution among the array elements, H- and E-plane corporate feeding networks are efficiently implemented in each array configuration. Array configurations of 1, 2, 4 and 8 radiating layers are offered by the proposed modular array, where each radiating layer is formed by 8 H-plane SIW horn antennas. The simulated directivity for the array configurations ranges from 15.8 dBi to 23.8 dBi and the main beam direction remains fixed along the operating frequency band. The array design has been manufactured and proper agreement between simulated and measured results are observed. The measured impedance bandwidth in all the array configurations is from 35 GHz to 41 GHz (15.79% bandwidth) with a reduction in the E-plane beamwidth as the number of radiating layers increases.

Mitigation of Mutual Antenna Coupling Effects for Active Radar Targets in L-Band

In order to realize a compact L-band transponder design for the calibration of spaceborne synthetic aperture radar (SAR) systems, a novel antenna was developed by DLR. As with previous designs for different frequency bands, the future transponder is based on a two-antenna concept. This paper addresses the issue of antenna coupling between corrugated L-band horn antennas, which are operated in close proximity. The antenna coupling is analyzed via simulations and measurements by utilizing specifically defined coupling parameters. Additionally, improvements to further lower the mutual antenna coupling have been designed, tested, and are described in this paper.

DESIGN OF ANTENNAS FOR HYBRID FSO/RF TRANSMISSION SYSTEM

The purpose of this publication is to create and correctly analyse a secondary RF line for a hybrid FSO/RF system. Since we want to ensure almost 100% functionality, the design of a secondary RF line is very important. In our case, we have chosen two types of antennas. First, it was a helical antenna that achieves a high level of efficiency and much smaller dimensions compared to horn antennas. The second type was just a horn antenna. Its advantages are high efficiency, high gain, and narrow width of radiation angle. However, large disadvantages are dimensions and the price of these antennas. However, in both cases, we can say that these antennas are suitable for deployment to our hybrid FSO/RF system.

Selective Laser Melting Process of Al–Based Pyramidal Horns for the W-Band: Fabrication and Testing

In the context of exploring the possibility of using Al-powder Selective Laser Melting to fabricate horn antennas for astronomical applications at millimeter wavelengths, we describe the design, the fabrication, the mechanical characterization, and the electromagnetic performance of additive manufactured horn antennas for the W-band. Our aim, in particular, is to evaluate the performance impact of two basic kinds of surface post-processing (manual grinding and sand-blasting) to deal with the well-known issue of high surface roughness in 3D printed devices. We performed comparative tests of co-polar and cross-polar angular response across the whole W-band, assuming a commercially available rectangular horn antenna as a reference. Based on gain and directivity measurements of the manufactured samples, we find decibel-level detectable deviations from the behavior of the reference horn antenna, and marginal evidence of performance degradation at the top edge of the W-band. We conclude that both kinds of post-processing allow achieving good performance for the W-band, but the higher reliability and uniformity of the sand-blasting post-process encourage exploring similar techniques for further development of aluminum devices at these frequencies.