The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Massive multiple-input multiple-output (MIMO) is a promising technology for next generation wireless communication systems (5G). In this technology, Base Station (BS) is equipped with a large number of antennas. Employing high resolution analog-to-digital converters (ADCs) for all antennas may cause high costs and high power consumption for the BS. By performing numerical results, we evaluate the...
In this paper, an improved and low-complexity signal detection approach for large-scale multiple-input multiple-output (MIMO) systems has been proposed. This approach utilizes the preconditioning technique to accelerate the conventional detection algorithm based on Gauss-Seidel (GS) iterative method, and achieves a detection performance close to the minimum mean square error (MMSE) detection algorithm...
This paper concerns the uplink (UL) and downlink decoupled access in heterogeneous networks (HetNets) with multi-antenna base stations (BSs). Departure from the traditional minimum pathloss policy, a maximum UL signal-to-noise ratio (SNR) user association policy that takes account of multiple antennas at BSs is proposed. Based on the proposed association policy, the UL association probabilities and...
In massive multiple-input multiple-output (MIMO) mobile system, the computational complexity of signal detection increases exponentially along with the growing number of antennas. For example, the sub-optimal linear detection schemes, such as zero forcing (ZF) detector and minimum mean square error (MMSE) detector, always have to balance the performance and complexity resulted from the large-scale...
Using a properly designed power profile allows a decode and forward (DF) method to achieve the cooperative diversity. In this paper, we consider a detect and forward (DF) strategy in which we propose an ML detector at the destination of a MIMO relay network to collect diversity when the cooperating relay adopts a zero forcing (ZF) equalizer with a proposed power profile. We provide some analysis and...
This paper presents a thermal THz detector based on commercial CMOS technology working at room temperature consisting of a loop antenna and a NMOS temperature sensor. The THz electromagnetic wave is absorbed by the loop antenna at first, then the absorbed energy is converted into heat via a resistor. The temperature rise of the resistor is finally detected by a NMOS temperature sensor. The physical...
A low-noise readout interface integrated with an antenna-coupled FET-based terahertz (THz) detector is designed and fabricated in a 0.15-μm CMOS standard technology. The implemented readout includes a cascade of a preamplification noise reduction stage based on a parametric chopper amplifier, and a direct analog-to-digital conversion by means of an incremental ΣΔ converter, substituting the lock-in...
We present a THz heterodyne detector based on a single layer graphene field effect transistor (GFET) integrated with a bowtie antenna at 400 GHz. The heterodyne detection is achieved by coupling RF and LO signals quasi-optically to the same GFET. The down converted IF signal is extracted via a coplanar stripline connected to the GFET source and drain terminals. The measured IF bandwidth is 5 GHz.
Brownout refers to dust cloud created by the rotor downwash of a helicopter. When it occurs, the visibility becomes limited, or even null. The pilot can be desorientated and accident may happen. No existing imaging systems can see through dust clouds, in real-time and with sufficient resolution. Using waves between 100GHz and 1THz seems to be a good solution to make a compact and suitable imaging...
A study of different pixel implementations working around 300 GHz is presented. They are monolithically integrated in a standard low-cost CMOS process with a high performances read-out chain for signal processing. All the different pixel configurations are compliant with the integrated metal stack and the imposed density rules of the technology. A test-chip, composed of a total of 17 cases of study,...
The design and performance analysis are presented for a passive uncooled radiometer pixel suitable for integration in 28nm CMOS technology. In the configuration a single wideband antenna, operating from 200 GHz to 600 GHz, is connected to a pn-junction diode. Including the antenna-detector impedance mismatch, the detector shows an average NEP of 2.71 pW/√Hz such that, together with the antenna, the...
In this paper a preliminary characterization of an 8 × 6 pixels, FET-based THz imager with on-chip antennas is presented. The sensor was designed and fabricated in a standard 150 nm CMOS technology and it takes advantage of a Switched Capacitor Band-Pass Filter (SC-BPF) followed by a sampling and amplifying stage for the readout chain, implemented at the pixel level.
This paper describes general considerations for the design of highly efficient and distributed room-temperature Terahertz detectors and transmitters in (Bi)CMOS technologies. It discusses the design of industrial-grade scalable terahertz imaging systems. This necessitates a deep understanding of the process technologies front-end and the back-end, as well employing innovative architectures of terahertz...
We compare Terahertz detection by large-area to antenna coupled lumped element field-effect transistors (FETs). The large radiation resistance of Ra=72 Ω of the antenna coupled device improves the responsivity by a factor of 150 as compared to the antenna-less large area device. The LA-FET is an order of magnitude more sensitive than expected from theory.
In this paper a rigorous electromagnetic characterization of the setup for measuring the THz power radiated by pulsed photoconductive antenna is discussed. Such characterization is expressed in terms of efficiencies which quantify how much power is lost in the coupling between the various components involved in the measurement setup. The conducted analysis highlights how such efficiencies affect the...
In this paper, a novel, low-complexity, and hardware efficient signal detection algorithm and its corresponding VLSI architecture are proposed for massive multiple-input multiple-output (MIMO) systems. This method is based on the parallel Gauss-Seidel (PGS) iterative method, and achieves comparable detection performance as the linear minimum mean-square error (MMSE) detection. It successfully avoids...
There are open issues related to efficient rectifying device (diode) for effective applications on energy harvesting and detectors based on micro/nano antennas. Some technological approaches have been developed to improve diode performance at Terahertz (THz) and optical frequency regimes. Diodes based on Metal-Insulator-Metal (MIM) structure is one of the best candidates for this task, mainly due...
skCUBE is 1U cubesat designed and developed in Slovakia over a period of years from 2012–2015 with expected launch in to the low-Earth orbit in 2017. It carries an experimental very-low-frequency (VLF) radio waves detector, which will attempt to record whistlers — radio signals from dispersed radio frequency components of lightning's. A lot has been found about these radio waves caused by classical...
We report a highly-sensitive plasmonic nano-ring transistor for monolithic terahertz (THz) active antenna. By designing an ultimate asymmetric transistor on a metal-gate structure, more enhanced (180 times) channel charge asymmetry has been obtained in comparison with a bar-type asymmetric transistor of our previous work. In addition, by exploiting ring-type transistor itself as a monolithic circular...
Collaborative reception has been proposed to improves the frequency utilization efficiency in wireless networks. This paper proposes a novel iterative noise cancelling receiver with soft-output lattice reduction (LR)-aided detector, which improves further frequency utilization efficiency. The proposed receiver achieves near optimum performance by removing an equivalent noise generating in the MMSE...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.