scholarly journals Small-Size Meandered Loop Antenna for WLAN Dongle Devices

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Wen-Shan Chen ◽  
Chien-Min Cheng ◽  
Da-Huei Lee ◽  
Chun-Lin Ciou ◽  
Wei-Syun Sin ◽  
...  
Keyword(s):  
Frequency Band ◽  
Coaxial Line ◽  
Loop Antenna ◽  
Back Side ◽  
Antenna Gain ◽  
Front Side ◽  
Radiation Patterns ◽  
Higher Modes ◽  
Half Wavelength ◽  
Via Holes

This paper proposes a loop-type USB dongle antenna, which is fabricated on a 1.6 mm thick FR-4 substrate for WLAN band systems. The front side of substrate consists of a 50-ohm coaxial line and a multiarm monopole antenna, while the back side has a meandered loop antenna connected to the ground by two via holes. The meandered loop resonates half-wavelength mode at about 2.4 GHz and its higher modes. The higher modes excited by the multiarm monopole form the 5.2 GHz frequency band. The bandwidth of the antenna covers the IEEE802.11 a/b/g WLAN applications. The overall dimensions of the antenna of 30 × 13.75 × 1.6 mm3with an antenna area of 7.5 × 13.75 mm2and a planar structure are exactly suitable for applying in dongle devices. The measured results of radiation patterns, antenna gain, and radiation efficiency are also proposed and discussed in the paper.

scholarly journals Very compact UWB antenna with group delay improvement

2015 ◽  
Vol 12 (2) ◽  
pp. 197-204 ◽  
Author(s):  
Esmaeel Tahanian ◽  
Hamidreza Hasani
Keyword(s):  
Time Domain ◽  
Return Loss ◽  
Group Delay ◽  
Frequency Characteristics ◽  
Back Side ◽  
Antenna Gain ◽  
Uwb Antenna ◽  
Delay Variations ◽  
The Time Domain

In this paper, very compact (12mm?17mm) and simple UWB antenna is proposed. The achieved bandwidth of the presented antenna is from 3.05 GHz to 12.5 GHz and in the most of the bandwidth, the return loss is less than -20dB. In addition to frequency characteristics, time characteristics such as group delay variations for three different antenna positions, namely, front to front, back to back and side by side using CST MW studio are simulated and discussed. To improve the group delay variations, by changing the radius of the circle on the back side of the antenna, the antenna gain in different frequencies will be tuned, therefore, the time domain characteristics of the proposed antenna are greatly improved.

scholarly journals Reconfigured and Notched Tapered Slot UWB Antenna for Cognitive Radio Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Tamer Aboufoul ◽  
Akram Alomainy ◽  
Clive Parini
Keyword(s):  
Cognitive Radio ◽  
Impedance Matching ◽  
Ultra Wideband ◽  
Slot Antenna ◽  
Total Efficiency ◽  
Back Side ◽  
Radiation Patterns ◽  
Uwb Antenna ◽  
Design Concepts ◽  
Specific Frequency

A compact reconfigurable and notched ultra-wideband (UWB) tapered slot antenna (TSA) is presented. The antenna reconfiguration operation principle relies on 2 mechanisms: in the first mechanism a resonator parasitic microstrip line electrically coupled to the TSA is used to notch the TSA at a specific frequency and the second mechanism relies on changing the input impedance matching of the antenna by means of changing the length of a stub line extended from an additional tiny partial ground on the back side of the antenna. The reflection coefficient, radiation patterns, and gain simulations and measurements for the proposed antenna are presented to verify the design concepts featuring a very satisfactory performance. Total efficiency simulations and measurements are also presented to highlight the filtering performance of the reconfigured antenna. When the antenna was reconfigured from the UWB to work into multiple frequency bands, the radiation patterns were still the same and the total peak gain has slightly improved compared to the UWB case. In addition, when the antenna operated in the notched mode, the gain has significantly dropped at the notch frequency. The simplicity and flexibility of the proposed multimode antenna make it a good candidate for future cognitive radio front ends.

scholarly journals A Band-Rejection Vivaldi Antenna with High Selectivity Using Hybrid HRW/CCLL

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Mengfei Xiong ◽  
Junping Duan ◽  
Binzhen Zhang
Keyword(s):  
Frequency Band ◽  
Design Method ◽  
Directional Pattern ◽  
Impedance Bandwidth ◽  
Ieee 802.11A ◽  
Notch Band ◽  
Notched Band ◽  
Half Wavelength ◽  
Measurement Results ◽  
Vivaldi Antenna

A simplified notched design method for the Vivaldi antenna is exhibiting high frequency-band-selectivity characteristics. By suitably introducing half-wavelength resonator (HWR) and complementary capacitively loaded loop (CCLL), the notched-band selectivity is promoted while maintaining the wide impedance bandwidth of the antenna applicable for wireless communications. HWR is bent in the middle to focus the first notch pole, and the second notch pole is obtained by CCLL on the radiating patch. Additionally, the resonant frequency of the notched pole can be determined by the position and size of two loaded resonators in theoretical analysis, thereby realizing a wideband antenna with the desired notched band. Finally, the Vivaldi antenna of loading resonator was fabricated to verify the feasibility of this new method. Measured and simulated experimental results reveal that the antenna exhibits directional pattern in the passband, low gain at the band-rejection, and excellent selectivity within a frequency range. The simulation and measurement results are in good agreement. The proposed antenna achieves S11<−10 dB in 2.6–13.7 GHz and a notch band from 4.49 to 6.64 GHz to reject IEEE 802.11a and HIPERLAN/2 frequency band. Moreover, the proposed antenna has good frequency selectivity, and its gain is good enough in the passband with peak gain up to 10.8 dBi. This antenna design presents frequency suitability, demonstrating that a UWB antenna with a controllable notched band has been realized.

scholarly journals A Compact UWB Antenna with a Quarter-Wavelength Strip in a Rectangular Slot for 5.5 GHz Band Notch

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Pichet Moeikham ◽  
Chatree Mahatthanajatuphat ◽  
Prayoot Akkaraekthalin
Keyword(s):  
Frequency Band ◽  
Communication Systems ◽  
Notch Filter ◽  
Radiation Patterns ◽  
Frequency Range ◽  
Uwb Antenna ◽  
Antenna Structure ◽  
Rectangular Slot ◽  
Quarter Wavelength ◽  
Uwb Applications

The limitation of the electromagnetic interferences (EMIs) caused by UWB radiating sources into WLAN/WiMAX communication systems operating in the frequency band located around 5.5 GHz requires the adoption of appropriate design features. To this purpose, a notch filter integrated into an UWB antenna, which is able to ensure a better electrical insulation between the two mentioned communication systems with respect to that already presented by the authors Moeikham et al. (2011), is proposed in this paper. The proposed filter, consisting in a rectangular slot including a quarter-wavelength strip integrated on the lower inner edge of the UWB radiating patch, is capable of reducing the energy emission in the frequency range between 5.1 and 5.75 GHz resulting in lower EMIs with sensible electronic equipments working in this frequency band. The antenna structure has no need to be tuned after inserting the rectangle slot with a quarter-wavelength strip. The proposed antenna has potential to minimize the EMIs at a frequency range from 5.1 to 5.75 GHz. The radiation patterns are given nearly omnidirectional in plane and likely bidirectional in plane at all frequencies by the proposed antenna. Therefore, this antenna is suitable to apply for various UWB applications.

IMPROVEMENT OF DIPOLE ANTENNA GAIN USING 8 CBU AMC-EBG AND 8 CBU FSS

2017 ◽  
Vol 79 (4) ◽  
Author(s):  
Maisarah Abu ◽  
Siti Adlina Md Ali ◽  
Siti Normi Zabri
Keyword(s):  
Transport System ◽  
Ground Plane ◽  
Side Lobe ◽  
High Gain ◽  
Dipole Antenna ◽  
Intelligent Transport System ◽  
Antenna Gain ◽  
Radiation Patterns ◽  
Intelligent Transport

This paper investigates the performances of dipole antenna incorporated with and without 8 CBU AMC-EBG and 8 CBU FSS at 5.8 GHz. The designs are simulated on Rogers RO 3010. Due to the flexibility of the material used as a substrate, the effect of a different angle is investigated. Both 8 CBU AMC-EBG and 8 CBU FSS act as reasonably good ground plane for the dipole antenna and help improving the realised gain and improve the radiation patterns by push the front lobe at the same time reduce the side lobes. The maximum improvements led by dipole antenna with 8 CBU AMC-EBG thus 8.543 dB of realised gain achieved and the front lobe is pushed higher and the side lobe is significantly lowered than with 8 CBU FSS. The designs of dipole antenna with 8 CBU AMC-EBG and 8 CBU FSS can be applied as high gain  atenna for Intelligent Transport System (ITS).

scholarly journals Ultrawideband Low-Profile and Miniaturized Spoof Plasmonic Vivaldi Antenna for Base Station

2020 ◽  
Vol 10 (7) ◽  
pp. 2429 ◽  
Author(s):  
Li Hui Dai ◽  
Chong Tan ◽  
Yong Jin Zhou
Keyword(s):  
Radiation Pattern ◽  
Frequency Band ◽  
High Gain ◽  
Base Station ◽  
Ultra Wideband ◽  
Radiation Patterns ◽  
Low Profile ◽  
Simulation Results ◽  
Vivaldi Antenna ◽  
Good Agreement

Stable radiation pattern, high gain, and miniaturization are necessary for the ultra-wideband antennas in the 2G/3G/4G/5G base station applications. Here, an ultrawideband and miniaturized spoof plasmonic antipodal Vivaldi antenna (AVA) is proposed, which is composed of the AVA and the loaded periodic grooves. The designed operating frequency band is from 1.8 GHz to 6 GHz, and the average gain is 7.24 dBi. Furthermore, the measured results show that the radiation patterns of the plasmonic AVA are stable. The measured results are in good agreement with the simulation results.

scholarly journals Ferrite-Loaded Spidron Fractal Loop VHF Antenna for UAV Applications

2020 ◽  
Vol 10 (15) ◽  
pp. 5392 ◽  
Author(s):  
Won Bin Park ◽  
Young-Mi Park ◽  
Keum Cheol Hwang
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
Magnetic Loss ◽  
Low Frequency ◽  
Loop Antenna ◽  
High Frequency Band ◽  
Ferrite Material ◽  
Aerial Vehicle ◽  
Flat Ground ◽  
Good Agreement

In this letter, an electrically small Spidron fractal loop antenna operating in the VHF band is proposed. The ferrite material, which consists of a nickel-zinc combination, is loaded into inside of the loop antenna to increase the gain of the antenna in the low frequency band. To minimize the magnetic loss of the ferrite in the high frequency band, the amount and configuration of the ferrite are optimized using a genetic algorithm. Through this optimization step, the amount of the ferrite is decreased to 37.5% and the gain of the antenna in the high frequency band is improved. The size of the proposed antenna is 0.0242 × 0.0242 × 0.0051 λL3 at the lowest operating frequency. The proposed antenna was fabricated to verify the performance, and the simulated and measured results are in good agreement. The measured peak gains varied from −31.6 to −1.9 dBi within the measured frequency band. To examine the performance of the proposed antenna mounted on an unmanned aerial vehicle model (UAV), the antenna on a UAV was also simulated and the results were discussed. The simulated realized peak gains of the antenna on the UAV and on flat ground are similar.

The Mechanism of J-V “Roll-Over” in CdS/CdTe Devices

2007 ◽  
Vol 1012 ◽  
Author(s):  
Jie Zhou ◽  
Xuanzhi Wu ◽  
Yanfa Yan ◽  
Sally Asher ◽  
Juarez Da Silva ◽  
...  
Keyword(s):  
Back Side ◽  
Back Contact ◽  
Front Side ◽  
Current Voltage

AbstractThe “roll-over” phenomenon in current-voltage (J-V) curves of CdS/CdTe devices is recognized as a result of the formation of a higher back barrier. When Cu has not been intentionally added to the back contact, roll-over is understandable. However, the mechanism was unclear for forming J-V roll-over in a CdTe cell with a back contact containing Cu. We did extensive characterizations, including XRD, XPS, SIMS, TEM, and EDS, and “recontact” experiments to understand this phenomenon. The results show that the roll-over comes from the formation of Cu-related oxides at the back side of the device during processing, rather than the diffusion of Cu to the front side of the device. Discussions related to the J-V roll-over mechanisms will also be presented.

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