Metin, BilginBasaran, YasinCicekoglu, Oguzhan
7页查看更多>>摘要：In this paper, a dual output current-mode biquad filter with band-pass and low-pass outputs using MOS transistors and capacitors is presented. In these type of filters MOSFETs operating in saturation mode are used instead of standard active elements and transconductances of these transistors are utilized instead of resistors. In the study a voltage controlled current source (VCCS) based core filter circuit is presented. This circuit is used as a starting point for the complete filter design. After VCCSs are replaced by MOSFETs biased for operating in saturation region, a resistorless MOSFET-C type filter circuit is obtained with only seven transistors and two grounded capacitors. Also, an agile filter application for secure communication is given to illustrate the functionality.
原文链接:
NSTL
Elsevier
Lberni, AbdelazizSallem, AminMarktani, Malika AlamiMasmoudi, Nouri...
12页查看更多>>摘要：During the past few years the multi-objective metaheuristics have become the most skilled and fruitful algorithms that have gained a lot of popularity of analog designers. These algorithms have been implemented into an optimization-based design tool that can be used to size difficult and complex analog circuits. The optimization-based approach can be categorized into simulation-based, equation-based, or neural-network-based device sizing. In this paper, the simulation-based approach is used to generate the non-dominated set of points of the Pareto fronts. A particular interest is accorded to the multi-objective particle swarm optimization (MOPSO) algorithm as a priori the most adequate metaheuristic to apply in the field of analog circuit sizing. The performances of MOPSO compared to the non-dominated sorting genetic algorithm (NSGA-II) are evaluated for four analog circuits at different operating regimes of transistors such as weak inversion, linear and saturation region. Performance tests of the proposed method are conducted on these circuits in 0.18 mu m CMOS technology. The results show that the proposed method can be useful for the optimal design of integrated circuits, to meet the challenge of automated design in the microelectronics domain.
原文链接:- NSTL
- Elsevier
Demirkol, BusraAldababsa, MahmoudToka, MesutKucur, Oguz...
10页查看更多>>摘要：In this paper, the outage probability (OP) performance of antenna selection schemes is investigated in downlink non-orthogonal multiple access based energy harvesting amplify-and-forward relay network. In this network, base station with multiple antennas simultaneously communicates with multiple-antenna users via the relay, which is equipped with single transmit and multiple receive antennas and operates in half-duplex (HD) or fullduplex (FD) mode. The joint transmit-receive antenna selection and receive antenna selection schemes are employed in the first and second hops, respectively. For the proposed system, the closed-form expressions for the exact OP are derived jointly for HD and FD modes over Nakagami-m fading. Then, the corresponding asymptotic OP expressions are obtained. Finally, accuracy of our analyses is verified by simulations.
原文链接:- NSTL
- Elsevier
Romera Perez, AntonioPons Abenza, AlejandroQuesada Pereira, Fernando D.Hinojosa Jimenez, Juan...
8页查看更多>>摘要：This work presents a novel low-pass filter based on using dielectric materials, in the critical areas of the structure, to prevent high-power space condition adverse effects, like multipactor breakdown. It is shown that the use of dielectric pieces in the inverters of the filter leads to increased gaps between metallic parts in the irises. In addition, by completely filling up the air space in critical gaps, the multipactor breakdown thresholds can be increased. Moreover, they also lead to a volume reduction, increasing compactness of the structure. To demonstrate the proposed concept, a prototype has been manufactured with an aluminum housing and a Teflon dielectric material, and tested for multipactor effect at ESA-VSC Laboratory. Tests confirmed that the manufactured filter has good electrical performance with cut-off frequency 13.6 GHz, insertion losses 0.32 dB, return losses better than 15 dB, and additionally does not show multipactor breakdown up to the maximum power tested in the experimental facility (5.5 kW).
原文链接:- NSTL
- Elsevier
Benmahmoud, FatehLemaitre-Auger, PierreTedjini, Smail
10页查看更多>>摘要：In this paper, a novel multi-arm crooked wire antenna designed with a multi-objective genetic algorithm (MOGA) is presented. The proposed topology offers a small size, lightweight, and a wideband -10 dB impedance matching. Its fully metallic nature preserves a high radiation efficiency. The multi-arm topology is discussed, and the impact of the number of arms and segments is studied. A proof of concept is optimized, fabricated, and tested. It occupies a volume less than 0.11 lambda x 0.13 lambda x 0.14 lambda, where lambda is the wavelength at the lowest operating frequency and covers the entire Global Navigation Satellite System services frequencies with a bandwidth of 503.5 MHz which represents 35.56%, without any matching network. The antenna's fully metallic structure results in a radiation efficiency higher than 98% and a gain of 8.66 dBi. Measurement results agree with simulations and are elaborated around the frequencies of the lower (1164-1300 MHz) and upper (1559-1610 MHz) bands of the L-band spectrum. A realization-friendly fabrication technique is proposed to realize the 3-D multi-arm wire antennas with high accuracy. The rigid fully metallic structure makes the antenna very suitable to operate in harsh environments, as in aerospace and military applications where substrate-based antennas are unqualified.
原文链接:- NSTL
- Elsevier
Nejadhasan, SajadZaheri, FatemehAbiri, EbrahimSalehi, Mohammad Reza...
17页查看更多>>摘要：In this paper, a new compensation technique for the low noise amplifier (LNA) with the high capability and efficiency for low power applications is proposed. The supply voltage and bias of the LNA are near the subthreshold voltage, which has excellent effect on reducing power consumption. At this voltage level, the gain decreases and the various circuit parameters become extremely sensitive to process, voltage and temperature (PVT) changes. To overcome the problem, a compensating circuit with variable current source to control the LNA bias voltage is used. The output of the compensator circuit is adjusted according to changes in temperature, voltage and five process corners, and produces a variable voltage. The temperature compensator consists of two current sources that produce a current proportional to temperature changes. Regarding process and voltage compensator, according to the state created in the circuit, the appropriate amount of current is injected through the output and finally stabilizes the main parameters of the LNA circuit. In LNA circuit, for proper performance at supply voltage near the sub-threshold and attaining the gain improvement, forward body bias and gm-boosting techniques are employed, respectively. The LNA circuit along with the PVT compensator at supply voltage of 0.35 V, consumes about 567 mu W power consumption that here 91 mu W is caused by the PVT compensator circuit. In the proposed circuit, the rate of noise figure (NF) and gain (S21) changes compared to temperature changes in the five corners have decreased by 4.3 and 12.1 times versus LNA with constant bias, respectively. In this case, with 20% changes of VDD, NF and S21 changes decreased by 23 and 11.35 times, respectively. The results are provided by Cadence software using 65 nm CMOS technology.
原文链接:- NSTL
- Elsevier
Habashi, AsiehGhobadi, ChangizNourinia, Javad
11页查看更多>>摘要：This letter presents a bi-layered chiral metasurface to achieve angularly stable dual-broadband cross-polarization conversion and asymmetric transmission properties of electromagnetic waves with linear polarization. In this regard, any unit cell of the recommended chiral metasurface consists of two new h-shaped resonators configured on two opposite sides of a dielectric slab. Investigations of the simulated and experimental electromagnetic responses validate that the impinging x - (y-) and y - (x-) polarized waves can convert into transmitted y (x-) and x - (-y) polarized waves at 7.5-8.6 GHz and 15-16.6 GHz, if the incident waves pass through the structure along -z (+z) direction, respectively. The obtained polarization conversion ratio (PCR) and asymmetric transmission parameters are more than 0.9 and 0.55 at both operated frequency bands, sequentially. Therefore, the proposed CMS has a significant potential to transform x- and y- polarized waves to orthogonal ones over the related frequency bands. The mechanism of the polarization conversions for any incident polarized wave has been verified by studying surface current distributions.
原文链接:- NSTL
- Elsevier
Badi, Susanta KumarAcharya, Om Prakash
9页查看更多>>摘要：In this article, a two element mutiple-input multiple-output (MIMO) antenna is designed to operate in 4.98 GHz to 6.04 GHz. The antenna has inter-element edge to edge spacing of 0.4 mm (approximate to 0.013Ag/0.00664 A0, where Ag and A0 are the guided and free space wavelength respectively at the lowest resonant frequency 4.98 GHz) which is extremely smaller than Rayleigh resolution distance. In spite of this, an acceptable port isolation is achieved by employing a stub in the common ground. Each radiating element comprises of etched rectangular patch having largest dimension approximate to 0.6 Ag fed with 50 ohm microstrip line. The proposed MIMO has overall size of 40 x 26 x 1.67 (approximate to 1.34 lambda g x 0.87 Ag x 0.056 Ag) mm3. Furthermore, the diversity parameters such as envelope correlation coefficient, diversity gain and mean effective gain have been studied in non-uniform medium. The total active reflection coefficient (TARC) and loss in channel capacity are found to be remain within the acceptable limit to exhibit the desired performances. The proposed antenna can be applied in 5G (below 6 GHz), WLAN and Wi-Fi bands.
原文链接:- NSTL
- Elsevier
Kalraiya, SachinChaudhary, Raghvendra KumarAbdalla, Mahmoud A.
9页查看更多>>摘要：In this study, a resistor-loaded wideband conformal metamaterial absorber has been designed, fabricate, and analyzed experimentally. The proposed absorber consists of lumped resistors loaded on cross-shaped resonators at the top side of the flexible substrate and copper metal film separated by flexible foam on the substrate's backside. The total thickness of the absorber is 0.07 lambda o, where lambda o is the lowest absorption frequency. The simulated results exhibited absorption from 3.25 - 13.6 GHz (absorption bandwidth 123%). The wideband absorption mechanism of the absorber was analyzed through the equivalent circuit model and parametric study. The designed structure has been tested on the planar and curved surfaces and measured the results. The simulated and experimental results have good agreement between them. The designed absorber can be suitable for scientific and military applications as of its wideband absorption bandwidth, polarization-insensitive, and conformability.
原文链接:- NSTL
- Elsevier
Khalaj-Amirhosseini, MohammadBoozari, Mahdi
7页查看更多>>摘要：An analytical method is proposed to synthesize arbitrary patterns for linear, ring and planar antenna arrays. It is well-known that the radiation pattern of an antenna array can be described by the ultra-spherical polynomials. Some ultra-spherical functions such as the Tschebyscheff and Legendre polynomials have been introduced in the literature. Using the orthogonality property of ultra-spherical functions, a closed form expression can be obtained for any arbitrary array factor. The array's excitation coefficients are then determined using a matrix-based system of equations. This system is solved using the Moore-Penrose pseudo-inverse principle, and the excitations of the array elements are calculated. The proposed method is demonstrated to be capable of designing linear, circular, and planar arrays. To validate the performance of the introduced method, several practical arrays are considered. The obtained results validate the benefits of the presented method in synthesizing radiation patterns for various types of linear and planar arrays.
原文链接:- NSTL
- Elsevier
