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M. Mohammedi Merah - IEEE Xplore Author Profile

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This paper analyzes state-of-the-art antenna concepts in the higher millimeter-wave frequency range (90-300 GHz), commonly referred to as the sub-THz frequency range. As the sub-THz range is still an emerging field of research, the aim of this review is to present and discuss different approaches and concepts reported in literature in the areas of antenna-in-package (AiP), antenna-on-chip (AoC) an...Show More
Statistics is a necessary tool to asses the uncertainties in a measurement technique. In this way, we can determine the reliability of the technique and can aim to improve this. In measurement techniques where both the amplitude and phase are important, statistics should be applied not only to the magnitude, but also to the phase. Linear statistics has several disadvantages when applied to the pha...Show More
This paper presents a fast exponential analysis and variable projection method to reduce the number of elements in linear phased arrays. The numerical examples given in this work demonstrate a reduction of approximately 20% or 10% in the number of elements, with only a slight decrease in directivity of 0.63 dBi observed for a scan range of $[-45^\circ,45^\circ ]$. Compared to the combined matrix p...Show More
This paper analyses the impact of assembly, process, voltage and temperature variations on the performance of a 4-channel power amplifier integrated into a waveguide with a direct waveguide-to-IC contactless transition. The paper reports on modeling methodology and presents simulation results of the impact of the variations on the performance of the waveguide-integrated power amplifier. Based on s...Show More
This article introduces the packaging and integration of a multichannel silicon-based power amplifier (PA) operating in the range of 70–74 GHz into a metal waveguide (WG) using a contactless IC-to-WG transition. This contactless transition facilitates the IC-WG connection and incorporates a spatial power combiner and an impedance matching network. This article outlines a comprehensive step-by-step...Show More
State-of-the-art conformal array pattern synthesis techniques typically suffer from a significant computational burden. This article builds upon the auxiliary array pattern synthesis technique, allowing the technique to work on elliptical contours. This deterministic method is both computationally efficient and capable of handling complex design cases with additional design constraints. In order t...Show More
No measurement is complete without a thorough investigation of the involved uncertainties. This article investigates uncertainties introduced by the probe in planar near-field (NF) measurements at the mm-wave frequencies 90 and 140 GHz. This includes probe compensation and multiple reflections between the probe and the antenna-under-test (AUT). A combination of simulations and measurements is used...Show More
Reverberation chambers are widely recognized as a time-efficient testing facility for various applications. The spatial uniformity based on the power transfer function is a critical characteristic of the chamber that affects the measurement uncertainty. To gain more insights into the chamber behavior we introduce a complementary metric: the K-gamma factor. This metric, inspired by the well-establi...Show More
This paper describes the analysis of a nine element test array of inverted V-antennas for the frequency range 20–90 MHz. The array is used as a small radio telescope. The purpose of this test array is to verify a system model using simulated embedded element patterns and measured impedances of the low noise amplifiers in a representative system. The output power of the array is measured over a per...Show More
To ensure effective plane wave illumination of an antenna under test in an anechoic chamber, a specific region known as the Quiet Zone (QZ) is typically specified. Conventional anechoic chambers often employ the industry-standard free-space voltage standing wave method utilizing a horn antenna for the QZ characterization. However, to define the QZ in distinctive anechoic chamber designs, it is ess...Show More
A preliminary study of the applicability of mm-waves for future body-centric wireless communication systems is presented. The loss levels associated with body-centric wireless propagation at lower mm-wave frequencies are quantified by over-the-air measurements of a propagation scenario, in which a custom-made human-head phantom is placed between two antennas to obstruct the line of sight. Both pas...Show More
In this article, we design and verify a millimeter-wave (mmWave) reverberation chamber (RC) operating in the 24–140-GHz band. The chamber is designed to facilitate over-the-air measurements of next-generation integrated antennas operating at high frequencies. For such systems, it is important to perform fast and accurate measurements of the radiated or received power over a wide frequency range. T...Show More
This letter describes the effects of atmospheric attenuation on reverberation-chamber measurements in the mmWave range. It is evaluated using chamber-decay time, as the atmospheric attenuation is also defined as the rate of decay. We describe a method to de-embed atmospheric attenuation to evaluate for which cases it has a measurable impact and show results from 50 to 140 GHz, including uncertaint...Show More
This communication concerns the design, simulation, and measurement of a multimode antenna array that provides ultrawide-angle scanning for emerging mm-wave applications. The proposed design is based on a half-loop antenna topology that is optimized for edge-fire radiation and is suitable for integration into mobile user equipment (UE). Each array element has two radiation pattern modes supported ...Show More
This paper presents the design of an antenna array specifically tailored for wide-angle scanning in mm-wave applications. The proposed design utilizes a half-loop antenna topology optimized for edge-fire radiation, making it highly suitable for integration into mobile user equipment. Each array element features two independent ports supporting two distinct radiation pattern modes, enabling coverag...Show More
This paper presents an exponential analysis technique for synthesizing a sparse non-uniform linear array using equidistant samples of the array factor of a dense uniform linear array. The problem statement is explored in a realistic production noise setting (i.e., we model uncertainties/tolerances during production as Gaussian noise), which motivates some slight oversampling. The collected samples...Show More
Modern wireless systems, especially at millimeter-wave, place increasingly stringent requirements on size, weight, power and cost (SWaP-C). In this talk we present an overview of our recent work on active beamsteering array antennas for mm-wave sensing applications, highlighting an active transmitarray antenna for Kaband (34-36 GHz) monopulse tracking radar with commercial SiGe-based beamforming c...Show More
In this paper, we present a hemispherical Fabry-Pérot open cavity resonator based measurement technique to estimate the relative permittivity of dielectric materials. The open cavity is realized by combining a spherical and a planar mirror, suitable for the characterization of both solid and fluid materials in the frequency range from 25 GHz to 42 GHz. The planar mirror is surrounded by a 0.5 mm h...Show More
This paper presents a model of active-integrated power amplifiers and antennas in a scanning array environment. The model links together load-pull data and unit-cell antenna simulations through a synthesized power combining and matching network to determine the active load reflection seen by the individual transistors. From this an estimate of the overall power-added efficiency, interconnect losse...Show More
In this contribution, radiation pattern measure-ments of a focal plane array antenna are combined with simulated outphasing waveforms to investigate the radiated spectrum. The recombination of the outphasing signals takes place in free-space (LINCA). The dynamic range is calculated and it is discussed whether the spectral masks would be violated with this system. A dynamic range of 24.1dB can be a...Show More
Conformal array pattern synthesis represents a challenging problem for current state-of-the-art design techniques. To their detriment, these techniques typically suffer from a significant computational burden. A deterministic method for the synthesis of singly curved conformal antenna arrays based on the superformula and the auxiliary array pattern (AAP) formulation is presented. This method, bein...Show More
In this paper, a novel multi-mode millimeter-wave antenna array with enhanced scan range and reduced scan losses is presented. The individual array element consists of a differentially fed microstrip patch on top of which a cylindrical dielectric resonator is integrated. The radiation pattern of the antenna element can be reconfigured by changing the phase offset between the feeding ports of the p...Show More
Active millimeter-wave beamforming arrays and focal plane array antennas require extensive calibration to compensate for impairments, such as phase and gain variations between elements, as well as unintended coupling between changes in gain and phase. When far-field calibration methods are used for calibrating focal plane array antennas, the required size of the anechoic chamber is exceedingly lar...Show More
Quantification of uncertainties in the results of channel sounding measurements is important for their interpretation and further usage. In this paper, a novel uncertainty analysis methodology to quantify uncertainties of condensed parameters in measurements of dynamic millimeter-wave channels is presented. The bandwidth limitation and multipath threshold are identified as important impairments. T...Show More
Receiving systems for mm-wave applications are increasing in complexity and level of integration. Therefore, crucial metrics such as noise figure have to be characterized using an over-the-air approach. We introduce a simplified version of the reverberation-chamber noise-figure (RCN) method, such that two instead of three calibration steps are necessary for the measurement of noise figure and gain...Show More