This communication describes the performance of the dual-circularly polarized transmitarray antennas at the Ka-band with independent radiation characteristics. The proposed antenna architecture consists of a dual-linearly polarized (dual-LP) TA panel based on the interleaving technique combined with an add-on broadband polarizer to generate independent right-handed circular polarization (CP) (RHCP) and left-handed CP (LHCP) beams. This offers both dual-LP and dual-CP operation depending on the topology of the polarizer. The LP unit-cell is designed to achieve a 3 bit phase resolution, and the dual-LP TA panel is made of two interleaved single-LP subarrays with 52 × 52 and 53 × 53 elements operating in 45° and 135° single LP, respectively. The polarizer transforms the dual-LP into dual-CP while keeping the radiation independence of each polarization across the Ka-band. The experimental results obtained with three different prototypes pointing up to 50° validate the proposed concepts.

In this contribution, we propose a hybrid electromechanical scanning antenna array architecture suitable for highly directive phased arrays at submillimeter wavelengths with field-of-views (FoV) of+/-30 degrees. The concept relies on combining electrical phase shifting of a sparse array with a mechanical translation of an array of lenses. The use of a sparse phased array significantly simplifies the RF front-end, while the translation of a lens array steers the element patterns to angles off-broadside, reducing the impact of grating lobes over a wide FoV. The mechanical movement of the lens array can be done using a low-weight, low-power piezo-actuator. In order to achieve wide bandwidth and steering angles, a novel leaky wave feed concept is also introduced. A 540 GHz prototype is currently under fabrication.

In this contribution, we propose an antenna for a dual-band focal plane array (FPA) heterodyne receiver at 210-240 GHz and 500-580 GHz to perform cometary observations. The proposed antenna is composed of a fused silica lens fed by a leaky wave waveguide feed. The dual-band leaky wave feed is based on a single-layer Frequency Selective Surface (FSS) with a transformer layer which allows to have a quasi-optical system that achieves a footprint of the field of view with overlapped beams and equal beamwidths for both frequency bands. A single pixel antenna prototype is currently being developed.

A new design methodology for dual band leaky-wave antennas is presented in the paper. The proposed methodology is based on the use of a single partial reflective surface (PRS) made with a Frequency Selective Surface (FSS) that fulfills the resonant condition at two different frequencies. This allows the design of a dual band leaky wave antenna including the control on the directivity at each one of the frequencies. Two examples of the application of this method (one with identical directivities at the two frequencies and the other one with different directivities) are presented.

In this paper, a leaky-wave fed lens antenna working at G-band for future XG communications is presented. A lens with a diameter of 16λ₀is proposed in HDPE material with a feed matching better than-10dB over a 45% of relative bandwidth. Analytical tools have been applied to achieve an aperture efficiency higher than 80% in the entire frequency band. One prototype have been fabricated and measured and the results agree well with the generated from both analytical approach and full-wave simulations.

The exponentially increasing demand for highspeed wireless links can be only efficiently satisfied with the development of future XG wireless communication networks, based on higher carrier signal frequencies, starting from 100 GHz. In this contribution, a circularly polarized G-band leaky-wave fed lens antenna with an integrated dielectric grid polarizer is presented, which can fulfill the challenging requirements for these future XG networks. A design is proposed in low dielectric permittivity material with a feed matching better than -10dB over a 44 % of relative bandwidth. The circularly polarized lens aperture efficiency is higher than 75% over a 35 % relative bandwidth, with an axial ratio lower than 3dB. Analytical tools have been applied to optimize the lens aperture efficiency, validating the results via full wave simulations. A lens prototype has been now fabricated and is currently being measured.

Microwave three-dimensional near-field focusing with radial polarization using a holographic annular-slot antenna is demonstrated in this letter. This radial polarization can generate axially polarized focused fields in the near-field regime, which complements the more conventional synthesis of transversally polarized near-field focusing patterns. Moreover, it is shown that more symmetrical focal region is obtained thanks to the radial polarization for similar Fresnel number N and operation frequency. The theory is demonstrated with experiments for a design operating at 10 GHz, with aperture diameter D=6λ and a Fresnel number N=4.