Programa del congreso

We introduce a novel reflectarray unit cell based on a SIW cavity resonator, designed for operation at 18.7 GHz. It can achieve a full phase cycle of phase shifting and low losses, while keeping manufacturing requirements simple. Furthermore, by relying on a resonant cavity instead of open elements, inter-cell coupling effects are reduced. This can lower the approximation errors resulting from using the cell response under a fully periodic environment during the design process.

This contribution describes a dual-band polarizing reflectarray antenna for small-satellite communications. The proposed an-tenna has been designed to convert the incident dual-linearly polarized field into dual-circular polarization in K and Ka bands, generating a high gain beam as well. The unit-cell is composed of two layers of metallization, where each layer has orthogonal groups of dipoles and is designed to independently operate at a different frequency. The polarization conversion process has been generalized to operate with non-stacked dual polarization elements, which allows to use a single dielectric layer per operating frequency. Simulated results of a 20 cm polarizing reflectarray antenna with a dual-layer configuration show a maximum gain larger than 30 dBi and an axial ratio below 1.5 dB at both design frequencies (19.7 and 29.5 GHz).

In this contribution, two designs of dual-band reflectarray surfaces are proposed for coverage-enhancing applications in millimeter-wave 5G networks. The first design is based on a two-layer reflectarray panel with simultaneous operation at 28 and 39 GHz, which is able to generate two independent collimated beams in dual polarization (one beam at each frequency). The second design is based on a single-layer reflectarray that operates at 28 and 60 GHz. In this case, a beamforming technique has been applied to broaden the beams in the azimuth plane, in order to cover a wider angular range. The proposed reflectarrays can be used to enable wireless communications in millimeter-wave networks, providing coverage of blind zones in both indoor and outdoor scenarios.

Cost-effective multibeam millimeter wave antenna solutions are required to enable the deployment of 5G NR . The complex trade-off between system complexity and RF requirements (such as high gain, number of beams, beam scanning capability, ) needs to be carefully optimzed. Transmit-arrays (TAs) can provide a low-cost solution for multibeam operation by having aN feeding array placed at a given focal distance. However, the maximum number of feeds and cross-over levels are constrained by the focal distance to aperture diameter ratio (F/D). On the one hand, reducing the F/D allows designing more compact feeding array elements, on the other hand, it limits the maximum angle coverage due to scanning aberrations. In this work, we show that a TA optimized for operating simultaneously with low F/D and wide-angle coverage can improve the performance of this classical configuration. We design a Ka-band multibeam antenna with a TA fed by a 19x5 array of standard WR38 waveguide operating with F/D=0.34. It provides 25 dBi of gain with scan losses below 3 dB when scanning in a zenith plane up to -55 degrees, covering 80 degrees (-55 to 25 degrees) with cross-over levels around 3 dB.