International audienceDual-band transmitarray antennas are demonstrated at Ka-band with the capability of forming independent linearly polarized beams with a given polarization in each frequency band, while sharing the same radiating aperture. The proposed three-layer unit-cell is based on identical narrow microstrip patches printed on both receiving and transmitting layers and connected by a metallized via hole. The metal layers are printed on two identical substrates bonded with a thin film, and the designed unit-cell exhibits a 180 degrees phase resolution (i.e., 1-b phase quantization). The dual-band dual-polarized property of the transmitarray is achieved by interleaving unit-cells operating in the down-link and up-link frequency bands. Four different prototypes are characterized to demonstrate the relevance of the proposed concepts. A good agreement is obtained between the radiation patterns, gain curves, and cross-polarization levels measured and computed in both frequency bands and polarizations

This paper presents the design, optimization, fabrication, and characterization of an electronically steerable transmitarray with 2 bits of phase quantization per unit cell. The proposed transmitarray operates in linear polarization at Ka-band and is composed of 14×14 reconfigurable unit-cells. Four p-in diodes are integrated on each unit-cell to control the radiated field phase distribution across the transmitarray aperture. The prototype demonstrates experimentally pencil beam scanning over a 120×120-degree window, a maximum gain at broadside of 19.8 dBi, and a 3-dB fractional bandwidth of 16.2%.

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This paper presents the experimental results of a 2-bit electronically reconfigurable unit-cell for transmitarrays at Ka-band. The proposed unit-cell architecture is based on a six-metal layers design and three dielectric substrates. Two patch antennas are printed respectively on the top and bottom layers of the stack-up to achieve an antenna-filter-antenna structure. To implement the desired 2-bit phase resolution, two p-in diodes are bonded on each patch. The unit-cell has been fabricated and characterized in a specific waveguide simulator. The measurement results are compared to the simulated ones and show minimum transmission loss in the range 1.5-2.3 dB. The 3-dB fractional bandwidth is in the range 10.1-12.1%.

We present here a design of metal-only unit-cell for transmitarray antenna (TA) applications at Ka-band, and we introduce a solution to reduce the total number of layers by polarization manipulation. The corresponding unit-cell is based on a C-shaped slot radiating element, fabricated by laser ablation on a thin metal sheet and operating in linear polarization. Thanks to the rotation of the slot, polarization of radiated wave can be manipulated to any arbitrary direction, particularly in the orthogonal direction of the incident wave. By combining two unitcells with opposite rotation directions, we show that metal-only unit-cells made of three layers can be obtained, with a 360° phase shift, insertion loss lower than 1 dB and low cross-polarization level. This unit-cell with reduced profile is used to design several TA prototypes with a main beam direction pointing up to 50°. The experimental results demonstrate an 11% 3-dB fractional gain bandwidth with an aperture efficiency around 50% for a beam at boresight.

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International audienceThis paper demonstrates the numerical results of a 196-element linearly-polarized electronically reconfigurable transmitarray in Ka-band. The proposed array architecture is based on a wideband and low-loss unit-cell with 2 bits of phase resolution (90°-step between two consecutive phase states). The unit-cell size (length × width × height) is equal to 5.1×5.1×1.3 mm3 and it is composed of six metal layers, three dielectric substrates and two bonding films. Four p-i-n diodes are soldered on the radiating elements in order to control the transmission phase. The full-wave simulations of the transmitarray are in agreement with the results predicted by using an ad-hoc simulation tool based on analytical model and electromagnetic simulations. The transmitarray antenna presents a maximum gain of 22.9 dBi, corresponding to an aperture efficiency of 32.3%, and a side-lobe level equal to -18.1 dB at 29 GHz. The computed 3-dB gain-bandwidth is larger than 15.9% around 29 GHz. © 2017 IEEE

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