Design and Simulation of a Wide-Band LPDA

2014 ◽  
Vol 687-691 ◽  
pp. 4024-4028
Author(s):  
Si Hao Wang ◽  
Yong Li ◽  
Shen Ke Zhang

A reconfigurable wideband Log-Periodic Dipole Array (LPDA) is here in introduced. Built utilizing low cost it can cover frequencies from 0.2GHz to 2GHz, through the discrete adjustment of its elements. The gain of antenna in a given frequency band of operation can also be changed by the reconfiguration of its elements. The design, construction and testing processes are discussed and a performance analysis is made based on computer simulations. In this paper simulation software HFSS is used to get the optimization design of LPDA, and the simulation results are agree with the experimental dates appropriately.

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3123
Author(s):  
Ran Yang ◽  
Wenyi Liu ◽  
Wanjia Gao ◽  
Dingwei Kang

The performance of the ultrasonic transducer will directly affect the accuracy of ultrasonic experimental measurement. Therefore, in order to meet the requirements of a wide band, a kind of annular 2-2-2 piezoelectric composite is proposed based on doped PDMS. In this paper, the transducer structure consisted of PZT-5A piezoelectric ceramics and PDMS doped with 3 wt.% Al2O3:SiO2 (1:6) powder, which constituted the piezoelectric composite. MATLAB and COMSOL software were used for simulation. Meanwhile, the electrode materials were selected. Then, the performance of the designed annular 2-2-2 ultrasonic transducer was tested. The simulation results show that when the polymer phase material of the piezoelectric ultrasonic transducer is doped PDMS, the piezoelectric phase and the ceramic substrate account for 70% of the total volume, the polymer phase accounts for 30% of the total volume, and the maximum frequency band width can reach 90 kHz. The experimental results show that the maximum bandwidth of −3 dB can reach 104 kHz when the frequency is 160 kHz. The results of the electrode test show that the use of Cu/Ti electrode improves the electrical conductivity of the single electrode. In this paper, the annular 2-2-2 transducer designed in the case of small volume had the characteristics of a wide frequency band, which was conducive to the miniaturization and integration of the transducer. Therefore, we believe that the annular 2-2-2 piezoelectric composite has broad application prospects.


Author(s):  
Puji Handayani ◽  
Gamantyo Hendrantoro ◽  
Eko Setijadi ◽  
Ahmad Mauludiyanto ◽  
Muhammad Rendy Anggara

Metamaterial absorber is an electromagnetic wave absorber made from metamaterial. It basically works in narrow band frequency as it is designed in a particular shape that related to its resonance frequency. However, some applications, e.g., anechoic chamber, require metamaterial absorber that can work in a wide frequency band. This paper discussed the design of wide band metamaterial absorber using the combination of multiple unit cells. The unit cells type was split ring resonator (SRR). SRR had advantages in terms of its simple shape, it could have more than one resonant frequencies depending on the number of its ring, and its shape could be modified easily to obtain the desired resonant frequencies. We designed metamaterial absorber having good absorbtion rate in 2-10 GHz frequency band. To cover this wide frequency band, we used five unit cells which were arranged on a flat plane. Each unit cell had several resonant frequencies. The design was carried out using simulation software of CST (Computer Simulation System). The fabricated design was measured and the results shown that it had an absorbtion rate of 99% in the measured frequency band.


2015 ◽  
Vol 4 (1) ◽  
pp. 45 ◽  
Author(s):  
S. M. Ali Hamed ◽  
A. A. Osman

This paper presents a simple formulas for designing broadband concentric circular-loops antennas (CCLAs). The loop dimensions for widest bandwidth are expressented in terms of the resonance frequency of the driven loop. The analysis addresses both cases CCLAs with and without ground planes. The presented formulas are employed to design multiple CCLAs.  For example, a 3-elements CCLA of a maximum radius of 6.34 cm can be designed to operate with a voltage standing wave ratio (VSWR) < 2 over a frequencies band of a fractional bandwidth of 16.9% with a minimum directivity of 3.9 dB. Addionationally, a 4-elements CCLA of maximum radius of 15 cm can be design to operate in the frequency band extending from 825 MHz to 991 MHz (fractional bandwidth of 18.3%) with a VSWR < 2 and directivity higher than 5.2 dB over the entire band. Furthermore, the analysis shows that a 3-elements CCLA backed with a conducting ground plane improves the fractional bandwidth to 19.6% and directivity to 9.15 dB over the band of interest. The analytical results on designed antennas are validated with simulation results obtained by using the AN-SOF antenna simulation software. An excellent agreement is observed between analytical and AN-SOF simulations results.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 1381-1389
Author(s):  
Dezhi Chen ◽  
Chengwu Diao ◽  
Zhiyu Feng ◽  
Shichong Zhang ◽  
Wenliang Zhao

In this paper, a novel dual-stator permanent magnet machine (DsPmSynM) with low cost and high torque density is designed. The winding part of the DsPmSynM adopts phase-group concentrated-coil windings, and the permanent magnets are arranged by spoke-type. Firstly, the winding structure reduces the amount of copper at the end of the winding. Secondly, the electromagnetic torque ripple of DsPmSynM is suppressed by reducing the cogging torque. Furthermore, the dynamic performance of DsPmSynM is studied. Finally, the experimental results are compared with the simulation results.


Author(s):  
Esra Musbah Mohammed Musbah ◽  
Khalid Hamed Bilal ◽  
Amin Babiker A. Nabi Mustafa

VoIP stands for voice over internet protocol. It is one of the most widely used technologies. It enables users to send and transmit media over IP network. The transition from IPv4 to IPv6 provides many benefits for internet IPv6 is more efficient than IPv4. This paper presents a performance analysis of VoIP over WLAN using IPv4 and IPv6 and OPNET software program to simulate the protocols and to investigate the QoS parameters such as jitter, delay variation, packet send, and packet received and throughputs for IP4 and IP6 and compare between them.


2012 ◽  
Vol 497 ◽  
pp. 89-93
Author(s):  
Liang Liang Yuan ◽  
Ke Hua Zhang ◽  
Li Min

In order to process heterotype hole of workpiece precisely, an open abrasive flow polish machine is designed, and the optimization design of machine frame is done for low cost. Firstly, basing on the parameters designed with traditional ways, three-dimensional force model is set up with the soft of SolidWorks. Secondly, the statics and modal analysis for machine body have been done in Finite element methods (FEM), and then the optimization analysis of machine frame has been done. At last, the model of rebuild machine frame has been built. Result shows that the deformation angle value of machine frame increased from 0.72′ to 1.001′, the natural frequency of the machine decreased from 75.549 Hz to 62.262 Hz, the weight of machine decreased by 74.178 Kg after optimization. It meets the strength, stiffness and angel stiffness requirement of machine, reduces the weight and cost of machine.


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