Programa del congreso

An omnidirectional conformal array antenna has been implemented in air-filled waveguide technology for the 37-40 GHz band. The input port of the antenna is implemented by a standard WR28 rectangular waveguide. The TE10 mode excited in the rectangular waveguide is used to generate the TE01 mode inside a circular waveguide by a TE10-TE01 mode converter. The circular waveguide path is progressively expanded forming a radial waveguide structure, where the TE01 mode is also expanded and radially propagated by several radiating apertures. Due to the radial symmetry of the structure, an omnidirectional radiating performance with low ripple can be achieved. This structure has been 3D manufactured using the direct metal laser sintering technology. It has been measured in order to experimentally validate its performance. A very good agreement between simulations and measurements, a reflection coefficient below -10 dB, a low ripple omnidirectional performance in a conical cutting plane, a very low cross-polar radiation as well as a total efficiency higher than 73% are obtained. This conformal antenna design is proposed for 5G New Radio indoor applications.

In this communication, a half-mode waveguide based on Gap Waveguide technology for rapid prototyping is presented. A power divider is designed for demostration purposes. The power divider is constructed from two non-contacting metal pieces. The horizontally-polarized power divider is housed in the bottom piece. The height of the groove is about half that which would be required to propagate the fundamental mode. The top cover is a uniform pinned surface that acts as a High Impedance Surface (HIS) over the groove of the bottom plate. The simulated reflection coefficient shows values of less than -15 dB in the bandwidth of interest (28 to 31 GHz). This design stands out for its ease of fabrication and opens a horizon for cheaper and more robust GW designs for mass production.

This contribution presents the characterization of a stripline embedded in a coaxial system. The stripline has been manufactured using HIPS as the main substrate. The metallic strip has been manufactured on 50mm thick kapton film which is binded to the main substrate. The transmission line plays a very important role in the overall performance of the ultrawideband radiating element currently under development. A multiline method has been used for the characterization of

the stripline. The influence of the conductivity obtain in the fabrication of the conductive ink on the propagation characteristics of the transmission line is analyzed. Simulations and measurements assess the goodness and possible negative effects of the fabrication process to rely on it for future designs.

The design, manufacturing and characterization of

a Ku-band orthomode transducer (OMT) is presented in this

paper. The OMT topology uses a T-junction with a circular waveguide

body, two rectangular waveguides attached to the main

cylinder and having fundamental modes with different boundary

conditions at the symmetry plane. The short-circuited bottom of

the cylinder includes simple matching elements optimized along

the rest of the OMT for easing the manufacturing by Selective

Laser Melting (SLM) in a single block. The restrictions imposed

by this type of additive manufacturing are included in the design

process, to provide a structure with performance suitable for

satellite applications. A Ku-band prototype in the frequency

band 13.4 - 15.6 GHz is tested, obtaining return loss better

than 20 dB in this 15.2% band, with isolation of at least 45

dB between orthogonal polarizations. In addition, the results for

the insertion loss are better than 0.18 dB, showing the potential

of SLM in structures traditionally requiring spark erosion or

high-accuracy milling. The OMT has ben also characterized in

radiation, confirming the good experimental results.

This contribution describes the design process of a flat polarizer reflectarray antenna in Ka-band for high data throughput from nanosatellites. The reflectarray has been designed to focus a high-gain beam while converting the incident polarization from dual-linear polarization into dual-circular. The flat surface of the reflectarray simplifies the mounting of the antenna on the small spacecraft and the linear-to-circular polarization conversion allows to reduce the number of components in the feed chain, also reducing the cost and complexity of the antenna subsystem. A 165 mm reflectarray antenna operating in Ka-band (31.8-34.7 GHz) has been designed with and without the polarization conversion. The results prove that the polarization conversion can be achieved while maintaining the performance of the antenna.