Hamza Kaouach

Wideband Low-Loss Linear and Circular Polarization Transmit-Arrays in V-Band

Several linearly-polarized and circularly-polarized transmit-arrays are designed and demonstrated in the 60-GHz band. These arrays have a fairly simple structure with three metal layers and are fabricated with a standard printed-circuit board technology. The simulation method is based on an electromagnetic model of the focal source and the unit-cells, associated to an analytical modeling of the full structure. A theoretical analysis is presented for the optimization of the power budget with respect to the F/D ratio. Several prototypes are designed and characterized in V-band. The experimental results are in very good agreement with the simulations and demonstrate very satisfactory characteristics. Power efficiencies of 50-61% are reached with a 1-dB gain bandwidth up to 7%, and low cross-polarization level.

Using Gaussian optics measurement system to characterize a new wideband low-loss antenna-slot-antenna

A new type of unit cell featuring wideband low loss characteristics is proposed for transmit-arrays (TA) and frequency selective surfaces (FSS) in Quasi-Optical applications. The TA is realized as a non-uniform array of antenna-resonator-antenna (ARA) elements and the FSS is realized as a uniform array of ARA elements. Each ARA element is a three layer structure consisting of two patch antennas and a slot resonator. The ARA elementary cell is designed and verified using finite element method simulation. A free space Gaussian optics measurement system (GOMS) is utilized to characterize the elementary cell. The measurement results show a 20.7% -3dB (12.2% -10dB) bandwidth and a maximum in-band insertion loss of <;0.2 dB for 42 GHz.

Design and characterization of wideband high-efficiency unit cells for frequency selective surfaces in 10GHz-band

This paper investigates two new unit cells featuring wideband low loss characteristics for frequency selective surfaces (FSS) in X-band applications. The FSS is realized as a uniform array of the proposed unit cells. Each unit cell is a three layer structure consisting of two back-to-back microstrip patch antennas and a non-radiating resonator in the common ground plane. These proposed FSS elements have been designed and optimized using the finite element method simulation. A waveguide measurement system (WGMS) has been used to characterize the first cell (symmetric) and a free space Gaussian optics measurement system (GOMS) has been used to characterize the second cell (asymmetric). An excellent agreement has been obtained between the simulation and measurement in terms of impedance matching (S11<;-10 dB, 7.3% and 8.5% around 10 GHz for the two cells, respectively) and insertion loss (<; 0.4 dB at 10 GHz).

Bandpass Antenna-Filter-Antenna Arrays for Millimeter-Wave Filtering Applications

This paper introduces new wideband antenna-filter-antenna (AFA) uniform arrays that can be utilized as frequency selective surfaces (FSS) with low loss and sharp roll-off response, which are highly desirable characteristics for millimeter wave applications. The design adopts a simple 3layer single polarization structure consisting of two patch antennas and a resonator. Both simulations and measurements are used to characterize the performances of the proposed design. Overall results show 18.5% 10-dB bandwidth. For the targeted band the insertion loss is less than 0.2 dB. Possible applications include quasi-optical amps, grid mixers and radomes for aircraft radar antennas.