Technique for Antenna Gain Correction Based on Return Loss Compensation

Nowadays, many battery-operated SoCs for loT and environmental monitoring applications are equipped with temperature sensors. In these miniaturized systems, power and area are two critical concerns. One challenge for temperature sensors is that they are sensitive to process corners and random mismatch. Generally, a 2-point trim and systematic non-linear error removal are required, especially for resistor-based sensing front-ends with two types of resistors, whose spread is partially uncorrelated [1], [2]. These corrections are done off-chip and digitally in most publications. In particular for low power sensors, they may consume more power and area than the sensor itself when integrated on-chip [3]. This work presents a resistive temperature sensor that integrates on-chip analog offset, gain and non-linearity correction techniques, while keeping state-of-the-art power and size performance. The prototype consumes 2.98pJ/conversion with an area of 0. <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0023\text{mm}^{2}$</tex> including all the correction techniques and achieves <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$+0.7/-0.6^{\circ}\mathrm{C}$</tex> inaccuracy.

Purpose: Gain calibration for X-ray imaging systems with movable flat panel detectors (FPD) and intrinsic crosshairs is a challenge due to the geometry dependence of the heel effect and crosshair artifact. This study aims to develop a gain correction method for such systems by implementing the multi-acquisition gain image correction (MAGIC) technique. Methods: Raw flat-field images containing crosshair shadows and heel effect were acquired in 4 different FPD positions with fixed exposure parameters. The crosshair region was automatically detected and substituted with interpolated values from nearby exposed regions, generating a conventional single-image gain-map for each FPD position. Large kernel-based correction was applied to these images to correct the heel effect. A mask filter was used to invalidate the original cross-hair regions previously filled with the interpolated values. A final, seamless gain-map was created from the processed images by either the sequential filling (SF) or selective averaging (SA) techniques developed in this study. Quantitative evaluation was performed based on detective quantum efficiency improvement factor (DQEIF) for gain-corrected images using the conventional and proposed techniques. Results: Qualitatively, the MAGIC technique was found to be more effective in eliminating crosshair artifacts compared to the conventional single-image method. The mean DQEIF over the range of frequencies from 0.5 to 3.5 mm-1 were 1.09±0.06, 2.46±0.32, and 3.34±0.36 in the crosshair-artifact region and 2.35±0.31, 2.33±0.31, and 3.09±0.34 in the normal region, for the conventional, MAGIC-SF, and MAGIC-SA techniques, respectively. Conclusion: The introduced MAGIC technique is appropriate for gain calibration of an imaging system associated with a moving FPD and an intrinsic crosshair. The technique showed advantages over a conventional single image-based technique by successfully reducing residual crosshair artifacts, and higher image quality with respect to DQE.

Position-dependent microchannel plate gain correction in Rosetta's ROSINA/DFMS mass spectrometer

In modern world, communication devices need to be operated for more than one frequency bands. Lot of research works were carried out in the field of multiband antennas. The one major concern in the design of multiband patch antenna are the gain and bandwidth. Both gain and bandwidth of the multi band antenna can be improved for the better performance. In this paper a triangular multiband antenna is designed and the gain of the antenna is enhanced by the blend of reactive impedance surface and Frequency selective surface. The proposed antenna resonates 3.4 GHz, 4.2 GHz, 6.75 GHz,7.1 GHz, 7.5 GHz and 9.3 GHz with a better return loss and gain.

A small-size printed PIFA using capacitive coupled-fed excitation to generate multiple resonant modes at lower and higher frequencies for eight-band operation covering LTE700 /GSM850/900/DCS1800/PCS1900/UMTS2100/LTE2300/2500 WWAN applied in the mobile phone is presented. The proposed PIFA consists of a main coupling strip which is linked to the short-circuit to the system ground plane of the mobile phone via a long inductive shorting strip and a feeding plate totally occupying a size of 15×45 mm2 printed on one surface of the FR4 substrate having a volume of 45×115×1.6 mm3, making it promising for practical applications. The capacitive coupling feed allows the PIFA to generate two wide operating bands for covering 698–960 MHz and 1710–2690 MHz, synchronously. The measured antenna's return loss, antenna gain and radiation efficiency are obtained in the letter, which can meet the requirements of practical mobile phones perfectly.

The main objective of this article is to design a compact ring printed monopole antenna for WiBAN applications. The performance of antenna is measured based on gain, return loss, efficiency, radiation pattern, and operating bandwidth. The antenna is implanted into canola oil (for homogeneous material) and beef (for nonhomogeneous material). The final measured result shows satisfactory performance and good agreement with the simulated result. The result presented indicates that the gain of antenna is 0.8 dBi with 49% efficiency when antenna is implanted into canola oil, whereas the gain of antenna is −30 dBi with 0.04% efficiency when antenna is implanted into beef. The radiation patterns of antenna are changed depend on the size and material of human body model. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1053–1058, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27503

This paper designs, simulates, and analyzes the S-band microstrip patch antenna (MPA) for wireless applications. FR-4 (lossy) and Rogger RT/duroid, whose dielectric permittivity is 4.3 and 2.2, respectively, have been used as substrate materials. Simulation is done by computer simulation technology (CST) suite studio 2019 software. Simulations with FR-4 material showed that the return loss was -20.405 dB, the gain was 2.592 dB, the directivity was 7.47 dBi, the voltage standing wave ratio (VSWR) was 1.221, the bandwidth (BW) was 0.0746 GHz, and the efficiency was 34.69%. Also, Rogers RT/duroid material gives results of a return loss of -12.542 dB, a bandwidth (BW) of 0.0349 GHz, a gain of 8.092 dB, a directivity of 8.587 dBi, and an efficiency of 94.24%. The main goal of this antenna is to have a low return loss while getting as close as possible to a VSWR of 1. This will improve the antenna's gain, directivity, and efficiency compared to other antennas. Copper was used to make the patch and the ground, which were 0.35 mm and 0.0077 mm thick, respectively. The results obtained from the proposed antenna were better than those previously published in various in modern scientific journal and conference papers.

An Ultra wide band wearable antenna with coplanar waveguide feed is presented in this paper. The antenna was designed and fabricated in jeans substrate. A coplanar feed of 50 Ohm impedance was used so as to provide the antenna a uniplanar structure. The simulation results showed ultra wide band characteristics with return loss below -10dB for the entire band of 3.1GHz to 10.6GHz. The antenna was fabricated using copper tape with the geometry of antenna etched on it. The return loss of the fabricated antenna was measured for a frequency of 3GHz to 8GHz. Over this range the antenna return loss was found to be below -10dB and was found to be in agreement with the simulated results. In order to increase the gain of the antenna Artificial Magnetic Conductor (AMC) was used. It was found to be exhibiting AMC characteristics at multiple frequencies. This was attached to antenna geometry and simulation studies were carried out. The simulated results showed an increase in antenna gain.

In this paper, a new method for designing an active dual-band dipole antenna is proposed. The operating frequencies of the proposed antenna are 150 and 450 MHz that are usually used in military applications. Using a series stub is the main idea in the proposed dual-band antenna, where it makes an independent resonance frequency higher than the main resonance frequency of a conventional dipole. To make appropriate matching impedance in the two frequency bands, the technique of creating an internal coaxial cable is used. Furthermore, to improve the antenna gain, an amplifier is in series part connected to the proposed dipole antenna. The simulated and measured results of the return loss, radiation patterns and antenna gain show that this antenna has a good operation in both resonance frequencies.

Ultra-wideband (UWB) technology was nowadays increased in interest for various applications due to its distinctive characteristics where it able to carry signals passes through obstacles unlikely narrow-band frequency that tends to reflect the signal. Through this paper, a design of miniaturized implantable UWB antenna utilizing various bio-compatible materials is studied. These materials are to be compared and determined the best material to be used for the design in terms of its return loss, center frequency, bandwidth, antenna gain and total efficiency. The antenna is designed in a structure of circular-ring with slit patch antenna using CPW profile with dimension of 10×10 mm2. As for the materials used in this study are Silicon, PDMS and Teflon PTFE. Each of this substrate has a thickness of 0.5 mm, 2.5 mm, and 1.5 mm correspondingly. After comparing these three materials, the one that gives the best result is Teflon PTFE with return loss at 11.91 GHz and 5.58 GHz bandwidth that covers from 9.16 GHz to 17.74 GHz frequency range. The antenna gives out total gain and efficiency of 2.54 dB and 86.5% respectively.

In this paper, a novel design that improves the performance of conventional rectangular microstrip antenna is discussed. Design adopts basic techniques such as probe feeding technique with rectangular inverted patch structure as superstrate, air filled dielectric medium as substrate and slot embedded patch. Prototype of the proposed antenna has been fabricated and various antenna performance parameters such as impedance bandwidth, return loss, radiation pattern and antenna gain are considered for Electromagnetic-study. The antennas are designed for the wireless application operating in the frequency range of 3.3 GHz to 3.6 GHz, and UK based fixed satellite service application (3 GHz to 4 GHz), and are named as single inverted patch conventional rectangular microstrip antenna (SIP-CRMSA) and slots embedded inverted patch rectangular microstrip antenna (SEIP-RMSA), respectively. Measurement outcomes for SEIP-RMSA1 and SEIP-RMSA2 showed the satisfactory performance with an achievable impedance bandwidth of 260 MHz (7 %) and 250 MHz (6.72 %), with return loss (RL) of −11.06 dB and −17.98 dB, achieved gain of 8.17 dB and 5.17 dB with 10% and 8% size reduction in comparison with the conventional patch antenna.

This study was conducted to investigate the potential of utilizing conductive polymer nanocomposite for flexible type antenna application. The polyaniline (PANI) filled with graphene nanoplatelets (GNPs) nanocomposites were synthesized by an oxidative aniline polymerization in an acidic medium. The PANI/GNPs nanocomposites were then characterized by using various spectroscopy and imaging tools. It was found that the strong interaction between PANI macromolecules and GNPs flakes is caused by the strong ?-? conjugation between them, as validated by an increase of Id/Ig ratio of PANI/GNPs nanocomposites. As a result, it established a three-fold improvement for the electrical conductivity of PANI/GNPs nanocomposites, due to the larger amount of charge carrier transport at higher GNPs nanofiller loadings (1.00 wt.%). Later, the PANI/GNPs nanocomposites powder was applied to the cotton fabric by integrating it with a rubber paint slurry. Electrical conductivity, antenna gain, return loss, and radiation pattern of the antenna were reported. It was found that PANI/GNPs flexible textile antenna possessed a constant gain of 4.1809 dB, return loss at -13.154 dB, and radiation pattern which operated at 10.36 GHz for 100% improvement of electrical conductivity, in comparison with unfilled PANI. From these findings, it can be said that the development of wearable textile antenna utilizing PANI/GNPs nanocomposites on the cotton fabric as flexible radiation patch, has great potential for wireless communication purposes.

A novel miniature coplanar waveguide (CPW) fed octagon shaped slot antenna used for wireless local area network is proposed. The antenna is designed on a RT/duriod 5880 substrate with a permittivity of 2.2 and size of 16.5mm × 20 mm × 1.6mm to generate single resonant mode with bandwidth of 0.94 GHz (5.095 GHz–6.035 GHz) covering 5.2/5.8 GHz, antenna gain 3.55 dBi, VSWR 5.5GHz–1.062 and return loss (S11)–30.42 dB, respectively. The radiation patterns are broadside and bidirectional in the E — plane and almost omnidirectional in the H-plane. This antenna is suitable for wireless local area network applications. The fundamental parameters of the antenna such as return loss, VSWR, gain and polarization which meets the acceptable antenna standards are obtained. Simulation tool, based on the method of moments ZELAND IE3D version 12.0 has been used to analyze and optimize the antenna. These properties with compact and uniplanar structure make the antenna suitable in WLAN application.

A simple microstrip patch antenna was first used to study and its resonant frequency and bandwidth were observed. Based on the observations a Frequency Selective Surface (FSS) is proposed to improve the bandwidth, antenna gain and return losses of a patch antenna. Fabricated results of the return losses, radiation pattern and antenna gain of this patch antenna are also presented. Through the Fabricated results it has been proven that the microstrip antenna implanted with an FSS structure containing fractal cross elements has been converted into an antenna with good performance along with sufficient bandwidth and higher gain.

With the advancement of wireless communication systems in recent years, small size multiband antennas are in great demand for both commercial and military applications. The fractal geometry concept can be used to reduce antenna size. So fractal shaped antennas are good choice to reduce antenna size and get multiband behavior. A dual band elliptical fractal patch antenna is presented in this paper. Artificial Neural Networks (ANN) based approach is used for calculating the resonant frequency, return loss and gain of antenna. The back propagation algorithm is used to train the network. The results obtained by using this ANN approach are in agreement with the simulated results obtained using IE3D software.