scholarly journals On-Body Transmission Single-Band Diamond Dipole Antenna with Waveguide Jacket

Author(s):  
M. A. Abdullah ◽  
M. K. A Rahim ◽  
N. A. Samsuri ◽  
K. Kamardin

This paper presents the investigation of on-body transmission single-band diamond dipole antenna with three different jackets. The jackets are named as normal jacket, grounding jacket and waveguide jacket. The on-body transmission is measured using two flexible single-band antennas attach to the jackets. A man with the height of 180 cm and 75 kg weight becomes as a model for the real measurement. The measurement is conducted in small space area by using portable network analyzer with flexible network cable. The measurement results show that the best performance for on-body transmission is with waveguide jacket. 10 dB transmission improvement is archived when the antenna is placed above the waveguide jacket compared to the normal jacket. It is found that the transmission of the antenna is also depends on the antenna orientation and further transmission lossess occur when the antennas are placed above the grounding jacket.

2015 ◽  
Vol 719-720 ◽  
pp. 680-686
Author(s):  
Zhen Yu ◽  
Xiao Ying Ran ◽  
Jian Guo Yu

A wideband wedge-angle microstrip patch log-periodic antenna with 16 units operates at the center frequency 2.45GHz, is presented in this paper. Design an antenna interactive calculator with Visual Basic software to calculate and to adjust antenna parameters conveniently. Then, construct, simulate, and optimize the antenna model by use of Ansoft HFSS software. The patch log-periodic dipole antenna (LPDA) is tested by PNA3621 vector network analyzer. Measurement results show that the antenna has good characteristics with symmetrical radiation pattern, broad bandwidth, little number of side lobes, and voltage standing wave ratio with echo loss are relatively ideal in 2GHz~3.2GHz frequency range, which agree well with the simulation results.


2007 ◽  
Vol 546-549 ◽  
pp. 1661-1664
Author(s):  
Xiao Yan Wang ◽  
Fa Luo ◽  
Dong Mei Zhu ◽  
Wan Cheng Zhou ◽  
Hong Huan Wu

Csf/Si3N4 composites were prepared by hot-press sintering method using α-Si3N4 power, short chopping carbon-fiber and sintering additives. XRD analysis showed that the α-Si3N4 was almost completely transferred into β-Si3N4. The SEM micrographs of fractured surfaces showed that special network developed by rod-like β- Si3N4 grains. The flexure strength of 590±10MPa, and fracture toughness of 7.94±0.1MPa·m1/2 were achieved for the samples incorporated with 0.5wt% the carbon fibers .The microwave dielectric property of Csf/Si3N4 composites was measured at a frequency range of 8.2~18GHz by E8362B PNA series network analyzer. The real part (ε ′ ) of the permittivity of the Csf/Si3N4 composites increases from 10 to 58 with the rise of the content of carbon fibers in the composites, as well as the imaginary part increases from 0.03 to 98 at frequency of 9.375GHz. A strong frequency dependence of the real part was observed both in X and Ku bands.


2021 ◽  
Vol 21 (4) ◽  
pp. 291-298
Author(s):  
Chandana SaiRam ◽  
Damera Vakula ◽  
Mada Chakravarthy

In this paper, a novel compact broadband antenna at UHF frequencies is presented with canonical shapes. Hemispherical, conical and cylindrical shapes have all been considered for antenna configuration. The designed antenna provides an instantaneous frequency range from 370 to 5,000 MHz with omnidirectional characteristics. The antenna was simulated in CST Microwave Studio, fabricated and evaluated; the results are presented. The simulated and measurement results are in good agreement. The antenna has voltage standing wave ratio (VSWR) ≤ 1.9:1 in 400–570 MHz, 2,530–3,740 MHz and 4,180–4,620 MHz; it has VSWR ≤ 3:1 over the operating frequency range 370–5,000 MHz and the measured gain varies from -0.6 to 4.5 dBi over the frequency band. The concept of canonical-shaped antenna elements and the incorporation of triple sleeves resulted in a reduction of the length of the antenna by 62% compared to the length of a half-wave dipole antenna designed at the lowest frequency. The antenna can be used for trans-receiving applications in wireless communication.


Author(s):  
Azhari Bin Asrokin ◽  
Mohamad Kamal Bin A. Rahim

A balance-unbalance (balun) transformer is commonly used to connect the balance 100 Ohm twisted pair cable to the unbalance 50 Ohm network analyzer ports, but due to the limitations of the core (i.e. ferrite) inside the balun, the balun can only effectively operates at a certain band of frequencies. This limitation can be eliminated by using a 4-port vector network analyzer (VNA) which is done by connecting the VNA’s ports to each conductor end. The extracted S-parameters will then be transformed to a 2-port S-parameters in differential mode at both ports. To validate the measurement technique, S-parameter measurement by using the 4-Port Network Analyzer without any balun will be compared to the measurement which used the 2-Port Network Analyzer with the balun transformers. Two twisted pair cable distances are selected as reference which are 500, and 1000 meters with nominal copper diameter of 0.5mm. Based on the measurement results, the 4-ports measurement shows good correlation with the 2-ports measurement especially at 500m distance. This shows that the 4-ports measurement setup is suitable to be used to measure twisted pair copper cable and possible to measure at a higher frequency band such as up to 500 MHz but at a shorter twisted pair cable distance.


2013 ◽  
Vol 64 (3) ◽  
Author(s):  
Nazirah Othman ◽  
Noor Asmawati Samsuri ◽  
Norfatin Akma Ellias

This paper presents the effects of conductive medical implant on energy absorbed by the human body and the testicular area when exposed to near field electromagnetic radiation. A dipole antenna is used as the radiating source and it is placed in front of the trousers pocket. Two types of medical implants are used in this study: intramedullary nail and bone plate. Numerical simulations are performed by means of CST Microwave Studio. Results are discussed in terms of changes in SAR values due to the presence of conductive medical implant at 0.4, 0.9, 1.8 and 2.4 GHz. The results have indicated that the conductive intramedullary nail that is located inside the femur significantly increases the SAR. Maximum enhancement in SAR is found when the length of the intramedullary nail is approximately one wavelength of the respective frequency tested. The measurement results indicate good agreements with the simulation results at 2.4 GHz.


2011 ◽  
Vol 135-136 ◽  
pp. 954-959
Author(s):  
Chang Bao Wen ◽  
Yong Feng Ju ◽  
Li Liu ◽  
Ya Fei Jiang ◽  
Chen Zhao ◽  
...  

In the design process of surface acoustic wave (SAW) device based on multistrip coupler (MSC), the characteristics of interdigital transducer (IDT) and device can not been directly achieved, and the layout structure of device can not be observed and checked. To solve some problems, the design platform of SAW device based MSC was realized in the Matlab design environment using the modular design. The design platform of SAW device based MSC consists of layout simulation module, characteristics simulation module and data output module. By means of realizing a SAW device based MSC with center frequency at 51.293MHz, the comparison and analysis between the design results and the actual test results are presented. Experiments results confirm that the platform can correctly design the device layout. The device characteristics achieved by the design platform are in good agreement with the actual measurement results by the network analyzer.


Frequenz ◽  
2017 ◽  
Vol 72 (1-2) ◽  
Author(s):  
Chen-yang Shuai ◽  
Guang-ming Wang

AbstractA simple ultra-wideband magneto-electric dipole antenna utilizing a differential-fed structure is designed. The antenna mainly comprises three parts, including a novel circular horned reflector, two vertical semicircular shorted patches as a magnetic dipole, and a horizontal U-shaped semicircular electric dipole. A differential feeding structure working as a perfect balun excites the designed antenna. The results of simulation have a good match with the ones of measurement. Results indicate that the designed antenna achieves a wide frequency bandwidth of 107 % which is 3.19~10.61 GHz, when VSWR is below 2. Via introducing the circular horned reflector, the designed antenna attains a steady and high gain of 12±1.5dBi. Moreover, settled broadside direction main beam, high front-to-back ratio, low cross polarization, and the symmetrical and relatively stable radiation patterns in the E-and H-plane are gotten in the impedance bandwidth range. In the practical applications, the proposed antenna that is dc grounded and has a simple structure satisfies the requirement of many outdoor antennas.


2014 ◽  
Vol 899 ◽  
pp. 147-150 ◽  
Author(s):  
Dušan Katunský ◽  
Marek Zozulák ◽  
Kristián Kondáš ◽  
Jozef Šimiček

Window sill of brick walls is one of the most critical places in a connection of two envelope types objectively. If there are the transparent and opaque parts present together, the connection is much more complicated. Different behavior of the construction materials in dynamic boundary conditions causes deformations of thermal field of the window sill detail. Numerical thermal field analysis verified by the experimental measurement in experimental outdoor chambers is used for recognize the real heat-air-moisture behavior in the various constructions.


2015 ◽  
Vol 9 (2) ◽  
pp. 341-348 ◽  
Author(s):  
Jin Zhang ◽  
Xianqi Lin ◽  
Jiawei Yu ◽  
Liying Nie

Patch antennas with a meandering slot and different distributions of grounded metallic vias are presented in this paper. The meandering slot is adopted to stimulate dual-band operation, while the number and position of the grounded metallic vias are suggested to achieve different radiation performances. The characteristics are analyzed in detail where we find that the existence of the vias also improves the impedance matching. Four samples are designed, where dual-band with both linear polarization, dual-band with circular- and linear-polarization, and single band with linear polarization are obtained, respectively. The samples are finally fabricated and the measurement results agree well with the simulation results.


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