scholarly journals Microwave losses of nanostructure Li-Ni ferrites in X-band and Ku-band

2019 ◽  
Vol 14 (29) ◽  
pp. 44-54 ◽  
Author(s):  
Sadeq H. Lafta
Keyword(s):  
Reflection Loss ◽  
Spinel Structure ◽  
Hydrothermal Process ◽  
Paramagnetic State ◽  
Molar Ratio ◽  
Mixing Ratio ◽  
Sem And Tem ◽  
X Band ◽  
Microwave Losses ◽  
Ku Band

The molar ratio(x) of Li-Ni ferrites in the formula Li0.5-0.5xNixFe2.5-0.5xO4 was varied in range 0.1-1.0 by hydrothermal process. TheXRD, SEM, and TEM tests were conducted to examine the samplescrystalline phase and to characterize the particles shapes and sizes.The high purity spinel structure was obtained at med and high xvalues. SEM and TEM images showed the existence of differentferrite particles shapes like nanospheres and nanorods. Themaximum particle size is around (20nm). These size encourageoccurrence of super paramagnetic state. The reflection loss andinsertion loss as microwave losses of Li-Ni ferrite-epoxy compositeof 1mm thickness and mixing ratio 39.4 wt was investigated. Theminimum reflection loss in x-band and in Ku band was about -8dBaround 10GHz and lower than -18dB respectively. The insertion lossexceeded -6dB in the two band for some samples.

Design and Analysis of Compact Triband Microstrip Antenna for X Band and Ku Band

2020 ◽  
Author(s):  
Muhammet Tahir Guneser ◽  
Cihat Seker ◽  
Seda Kersolar ◽  
Ibrahim Telli ◽  
Sevda Dilek Dogangun ◽  
...  
Keyword(s):  
Microstrip Antenna ◽  
X Band ◽  
Ku Band

Sol-Gel Synthesis and Characterization of Ultrafine ZrSiO4 Powder

2014 ◽  
Vol 906 ◽  
pp. 66-71
Author(s):  
Zhen Quan Li ◽  
Qiang Zhen ◽  
Ya Li Wang
Keyword(s):  
Wavelength Range ◽  
High Purity ◽  
Raw Materials ◽  
Formation Rate ◽  
Sol Gel ◽  
Molar Ratio ◽  
Sem And Tem ◽  
Homogeneous Product ◽  
Sol Gel Synthesis ◽  
Calcined Temperature

High purity ZrSiO4 powder were synthesized using Si (C2H5O)4 and ZrOCl2·8H2O as raw materials by the sol-gel method, LiCl was added as mineralizer to promote crystallization of zircon. The influences of molar ratio of Zr:Si, calcined time and calcined temperature on the synthesis of ZrSiO4 powder were investigated. XRD, SEM and TEM were used to characterize the powders. It was found that when the molar ratio of Zr:Si was 1:1.2, the calcined temperature was 1600°C and the calcined time was 4h, the high purity ZrSiO4 ultrafine powder was obtained. The ZrSiO4 formation began at 1300°C and when the gel was calcined at 1600°Cfor 4 h, the formation rate of ZrSiO4 was up to 95%. SEM and TEM studies reveal a homogeneous product with particle sizes on the order of 0.1-1μm. The IR emissivity of ultrafine ZrSiO4 is 0.892 at the whole wavelength range, and that is up to 0.951 at the wavelength range of 8-14 μm.

A Novel Multi-band High-Gain Slotted Fractal Antenna using Various Substrates for X-band and Ku-band Applications

MAPAN ◽  
2021 ◽  
Author(s):  
Aman Dahiya ◽  
Rohit Anand ◽  
Nidhi Sindhwani ◽  
Dhirendra Kumar
Keyword(s):  
High Gain ◽  
Fractal Antenna ◽  
X Band ◽  
Ku Band ◽  
Multi Band

A Highly Efficient Dual-Band Transmitarray Antenna Using Cross and Square Rings Elements

2021 ◽  
Vol 36 (7) ◽  
pp. 852-857
Author(s):  
Yongliang Zhang ◽  
Xiuzhu Lv ◽  
Jiaxuan Han ◽  
Shuai Bao ◽  
Yao Cai ◽  
...  
Keyword(s):  
Satellite Communications ◽  
Dual Band ◽  
Band Ratio ◽  
Maximum Gain ◽  
Aperture Efficiency ◽  
Dielectric Substrates ◽  
Highly Efficient ◽  
X Band ◽  
Transmission Phase ◽  
Ku Band

In this paper, a highly efficient dual-band transmitarray antenna using cross and square rings elements is presented for X and Ku bands. The dual-band transmitarray is designed for downlink/uplink frequencies of Ku band satellite communications. The transmitarray element consists of four metal patches and two dielectric substrates. The metal patch is printed on both sides of the substrate. By optimizing the parameters, the transmitarray element can achieve a transmission phase coverage greater than 360° and work independently in both frequency bands. Then, a method to select the size of the element is proposed, so that all the elements in the array can realize the transmission phase of the two frequencies as much as possible. A 201-elements transmitarray antenna is fabricated and measured and the band ratio of the antenna is 1.13. The measured maximum gain at 11.5 GHz is 22.4 dB, corresponding to the aperture efficiency is 52.7%. The measured maximum gain at 13 GHz is 24.2 dB, corresponding to the aperture efficiency is 62.4%. The 1-dB gain bandwidths are 9.7% (10.8-11.9 GHz) at X band and 9% (12.6-13.8 GHz) at Ku band.

Optimization of a broadband directional gain microstrip patch antenna for X–Ku band application

2013 ◽  
Vol 5 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Anubhuti Khare ◽  
Rajesh Nema
Keyword(s):  
Patch Antenna ◽  
Middle Layer ◽  
Microstrip Patch Antenna ◽  
Impedance Bandwidth ◽  
Microstrip Patch ◽  
Indirect Coupling ◽  
X Band ◽  
Different Dimensions ◽  
Rectangular Microstrip Antenna ◽  
Ku Band

In this paper, optimization of a microstrip patch antenna is presented. The optimization uses a genetic algorithm in the IE3DTM Simulator. The optimization is done in several steps, first by changing the position of parasitic patches on the top layer, second by placing a feeding patch at the middle layer of geometry, and third by indirect coupling between the top and middle layer patches. Overall, we have performed many possible iterations and found appropriate geometry. From this appropriate geometry we have achieved maximum directional gain (6.2–8.8 dBi) over a 6 GHz bandwidth slot, 38% impedance bandwidth of the X-band and 14.8% impedance bandwidth of the Ku-band. The broadband frequency of operation is demonstrated by single geometry. The geometry of a single probe fed rectangular microstrip antenna incorporating a slot, gap coupled with a parasitic and an active patch on geometry, has been studied. We have investigated the height between active and parasitic patches as 0.0525λ and the height between parasitic patches itself as 0.0525λ. We have investigated the enhancement in maximum directional gain by stacking geometry with one active patch and two parasitic patches of different dimensions. This optimized antenna is used for X-band and Ku-band applications. The hardware validation and simulation results are matched to the proposed design.

Temperature dependence of the electromagnetic and microwave absorption properties of polyimide/Ti3SiC2 composites in the X band

RSC Advances ◽  
2015 ◽  
Vol 5 (105) ◽  
pp. 86656-86664 ◽  
Author(s):  
Hongyu Wang ◽  
Dongmei Zhu ◽  
Wancheng Zhou ◽  
Fa Luo
Keyword(s):  
Temperature Dependence ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Absorption Bandwidth ◽  
X Band ◽  
Maximum Reflection Loss

The maximum reflection loss value of polyimide/Ti3SiC2 composites is up to −48.6 dB at 8.5 GHz with a thickness of 2.9 mm and the absorption bandwidth below −10 dB is 3.8 GHz.

scholarly journals Frequency-multiplexed pure-phase microwave meta-holograms using bi-spectral 2-bit coding metasurfaces

Nanophotonics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 703-714 ◽  
Author(s):  
Shahid Iqbal ◽  
Hamid Rajabalipanah ◽  
Lei Zhang ◽  
Xiao Qiang ◽  
Ali Abdolali ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Phase Retrieval ◽  
Dual Band ◽  
Retrieval Algorithm ◽  
Band Frequency ◽  
X Band ◽  
Pure Phase ◽  
Frequency Multiplexing ◽  
Information Channels ◽  
Ku Band

AbstractIn this paper, a dual-band reflective meta-hologram is designed providing two distinct information channels whose field intensity distributions can be independently manipulated at the same time. The proposed pure-phase meta-hologram is composed of several frequency-dispersive coding meta-atoms possessing each of 2-bit digital statuses of “00”, “01”, “10”, and “11” at either the lower (X-band) or the higher (Ku-band) frequency band. Relying on the weighted Gerchberg-Saxton phase retrieval algorithm, different illustrative examples have been provided to theoretically inspect the dual-band performance of our coding meta-hologram. Numerical simulations validate the proposed frequency multiplexing meta-holography with the ability to project two different high-quality images with low cross-talk on two X-band and Ku-band near-field channels located at distinct pre-determined distances from the metasurface plane. As proof of concept, two meta-hologram samples are fabricated, and the experimental results corroborate well the numerical simulations and theoretical predictions. The designed meta-hologram features all fascinating advantages of the coding metasurfaces while its performance overcomes that of previous studies due to providing two information channels rather than the conventional single-channel holography. The frequency multiplexing acquired by the proposed bi-spectral coding meta-hologram may provide great opportunities in a variety of applications, such as data storage and information processing.

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