scholarly journals REASERCH ON A WATER-IMMERSED WIDE BAND HORN ANTENNA WITH WATER-FILLED COAXIAL IMPEDANCE MATCHING STRUCTURE

2019 ◽  
Vol 77 ◽  
pp. 115-123 ◽  
Author(s):  
Yang Yang ◽  
Lianghao Guo ◽  
Qing Zhou ◽  
Zhe Wu ◽  
Haibo Jiang ◽  
...  
2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Danvir Mandal ◽  
S. S. Pattnaik

A novel wide coplanar waveguide- (CPW-) fed multiband wearable monopole antenna is presented. The multiband operation is achieved by generating slanted monopoles of different lengths from an isosceles triangular patch. The different operating frequencies of the proposed antenna are associated with the lengths of the slanted monopoles, which are determined under quarter wavelength resonance condition. The CPW line is used as a multiband impedance-matching structure. The two grounds are slightly extended for better impedance matching. The proposed antenna is designed to cover the 1800 MHz GSM, 2.4 GHz/5.2 GHz WLAN, and 3.5 GHz WiMAX bands. The measured peak gains and impedance bandwidths are about 4.18/3.83/2.6/2.94 dBi and 410/260/170/520 MHz for the 1550-1960 MHz/2.3-2.56 GHz/3.4-3.57 GHz/5.0-5.52 GHz bands, respectively. The calculated averaged specific absorption rate (SAR) values at all the resonant frequencies are well below the standard limit of 2 W/kg, which ensures its feasibility for wearable applications. The antenna performance under different bending configurations is investigated and the results are presented. The reflection coefficient characteristics of the proposed antenna is also measured for different on-arm conditions and the results are compared. A good agreement between experimental and simulation results validates the proposed design approach.


2011 ◽  
Vol 20 (07) ◽  
pp. 1231-1242 ◽  
Author(s):  
J. DEL PINO ◽  
SUNIL L. KHEMCHANDANI ◽  
ROBERTO DÍAZ-ORTEGA ◽  
R. PULIDO ◽  
H. GARCÍA-VÁZQUEZ

In this work, the influence of the inductor quality factor in wide band low noise amplifiers has been studied. Electromagnetic simulations have been used to model the integrated inductor broad band response. The influence of the quality factor on LNA performance of the inductors that compound the impedance matching networks, inductive degeneration and broadband load has been studied, obtaining design guidelines for optimizing the amplifier gain flatness. Using this guidelines, an LNA with wideband input matching, shunt-peaking load, and an output buffer was designed. Using Austria Mikro Systems BiCMOS 0.35 m process, a prototype has been fabricated achieving the following measured specifications: maximum gain of 12.5 dB at 3.4 GHz with a -3 dB bandwidth of 1.7–5.3 GHz, noise figure from 4.3 to 5.2 dB, and unity gain at 9.4 GHz.


Author(s):  
Sha Li ◽  
Yi Hua Yan ◽  
Wei Wang ◽  
Zhi Jun Chen ◽  
Dong Hao Liu ◽  
...  

AbstractIn traditional antenna design, metal components are not placed in the central part of the antenna as they change the characteristics of near field radiation. However, we show that placing a metal ring in the centre of the strip lines, which connect the ends of folded high-frequency dipoles, does not damage the performance of the feed. Instead it significantly improves the voltage standing wave ratio of the feed whilst other performance indicators are not compromised. Thus, our findings show an excellent way of improving the wide band feed. Based on this foundation, a new circularly polarised feed for operation between 0.4 to 2 GHz is introduced for the Chinese Spectral Radioheliograph in this paper. The issue of a feed impedance matching network is investigated. By optimising the impedance matching, the performance of the feed is enhanced with respect to the previous realisations of the Eleven feed. The simulation and experimental results show that the gain of the feed is about 10 dBi, and the VSWR is less than 2:1. In addition, the feed has a low axial ratio, fixed phase centre location, and constant beam width in the range of 0.4 to 2 GHz.


2017 ◽  
Vol 9 (8) ◽  
pp. 1741-1748 ◽  
Author(s):  
Mahdi Jalali ◽  
Mohammad Naser-Moghadasi ◽  
Ramezan Ali Sadeghzadeh

Wide-band circularly polarized multi-input multi-output (MIMO) antenna array with a 2 × 4 feed network was proposed for C-band application. Different unique techniques were utilized in the proposed array to enhance the antenna characteristics, such as gain, 3 dB axial ratio bandwidth (ARBW), impedance tuning, and ruinous mutual coupling effects. A miniaturized dual-feed Tai chi-shaped antenna element with a pair of feeding points and a pair of eyebrow-shaped strips was presented for enhancing circular polarization (CP) purity and impedance matching. For a better improvement of CP features, a 2*4 MIMO sequentially rotated (MIMO-SR) feed network was used to achieve broader 3 dB ARBW. Besides, the MIMO feature of the feed network could control the left- and right-handed CP, respectively. Ultimately, specific forms of slot and slit structures were applied onto the top layer of MIMO feed network that provided a high isolation between the radiating elements and array network. Furthermore, the diversity gain (DG) was studied. The extracted measured results illustrated an impedance bandwidth of 3.5–8.2 GHz at port 1 and 3.5–8.3 GHz at port 2 for VWSR < 2 and 3 dB ARBW of 4.6–7.6 GHz at port 1 and 4.6–7.5 GHz at port 2. The peak gain of 9.9 dBi was at 6 GHz.


Frequenz ◽  
2017 ◽  
Vol 71 (11-12) ◽  
Author(s):  
Naveen Jaglan ◽  
Binod Kumar Kanaujia ◽  
Samir Dev Gupta ◽  
Shweta Srivastava

AbstractA dual band-notched MIMO/Diversity antenna is proposed in this paper. The proposed antenna ensures notches in WiMAX band (3.3–3.6 GHz) besides WLAN band (5–6 GHz). Mushroom Electromagnetic Band Gap (EBG) arrangements are employed for discarding interfering frequencies. The procedure followed to attain notches is antenna shape independent with established formulas. The electromagnetic coupling among two narrowly set apart Ultra-Wide Band (UWB) monopoles is reduced by means of decoupling bands and slotted ground plane. Monopoles are 90° angularly parted with steps on the radiator. This aids to diminish mutual coupling and also adds in the direction of impedance matching by long current route. S


2013 ◽  
Vol 441 ◽  
pp. 154-157
Author(s):  
Yong Pan ◽  
Zi Ye Hou ◽  
Jiang Xiong ◽  
Kai Hua Liu

A miniaturized multi-frequency antenna is proposed. The proposed antenna can generate three separate impedance bandwidths to cover all the 2.4/5.8 GHz WLAN/RFID operating bands and the 2.5/3.5/5.5 GHz WiMAX bands. The proposed microstrip-fed antenna mainly consists of a circular ring, four semicircular rings, a rectangle strip, and a defected ground plane. By adding four semicircular rings in the circular ring, the antenna excites two resonant modes and is with miniaturization structure. Because of the introduction of the cambered ground plane with an circular-defect, the third wide band with better impedance matching is obtained. A prototype is experimentally tested, and the measured results show good radiation patterns and enough gains across the operation bands.


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