scholarly journals Dual-Band Quarter Mode SIW Cavity Back Slot Antenna

2020 ◽  
Vol 8 (5) ◽  
pp. 2182-2187
Keyword(s):  
Design Process ◽  
Experimental Results ◽  
Dual Band ◽  
Slot Antenna ◽  
Operating Mechanism ◽  
Circular Cavity ◽  
Dual Frequency ◽  
Resonant Frequencies ◽  
Magnetic Wall ◽  
The Operating Mechanism

A miniaturized quadrant slot antenna backed by the cavity using QMSIW technique is developed for dual-frequency applications. The design process is begun with FMSIW circular cavity which has been cut along magnetic wall twice to get quadrant sector of a circular cavity that is said to be a QMSIW cavity. The QMSIW cavity excited in TM210 and TM020 modes is loaded by quadrant slot which helps to decrease the resonant frequencies. The CST microwave studio is used to study the operating mechanism of various modes in the cavity. The antenna has been fabricated and measured the S11 and principle pattern and also compared with simulated results. The experimental results prove that the antenna S11 in dB is low at dual-frequency. One of the resonant frequencies is at 8.05 GHz and other 9.95 GHz with peak gains are around 6.25 dBi and 6.45 dBi respectively.

A Miniaturized Dual-Band FSS with Closely Spaced Resonances Using 2.5-Dimension Structure

Frequenz ◽  
2018 ◽  
Vol 72 (11-12) ◽  
pp. 511-515 ◽  
Author(s):  
Weiyang Yin ◽  
Hou Zhang ◽  
Tao Zhong ◽  
Xueliang Min
Keyword(s):  
Resonant Frequency ◽  
Free Space ◽  
Frequency Ratio ◽  
Surface Current ◽  
Dual Band ◽  
Operating Mechanism ◽  
Special Design ◽  
Measurement Results ◽  
Simulation Results ◽  
The Operating Mechanism

Abstract Using 2.5-dimension structure, a novel miniaturized dual-band FSS with closely spaced resonances is proposed in the paper. The special design of the geometry contributes to two closely spaced resonances at 1.69 GHz and 2.16 GHz respectively and the frequency ratio of upper to the lower resonant frequency is 1.27. Besides, the two bands can be controlled individually by varying corresponding parameters. The size of the proposed FSS is only 0.057λ0, where the λ0 represents free space wavelength at lower resonant band. Furthermore, the simulation results show the proposed FSS exhibits stable response with different incident angles and polarizations. To understand the design better, the distribution of surface current is analyzed to explain the operating mechanism of the proposed FSS. Finally, the proposed FSS is fabricated and the measurement results are in accordance with the simulation results.

A novel single-feed reconfigurable antenna for polarization and frequency diversity

2016 ◽  
Vol 9 (5) ◽  
pp. 1155-1161 ◽  
Author(s):  
Ailar Sedghara ◽  
Zahra Atlasbaf
Keyword(s):  
Circular Polarization ◽  
Simple Structure ◽  
Dual Band ◽  
Slot Antenna ◽  
Impedance Bandwidth ◽  
Frequency Diversity ◽  
Resonant Frequencies ◽  
Frequency Bands ◽  
Left Hand ◽  
Microstrip Feed

A novel dual-band single-feed reconfigurable annular-ring slot antenna with polarization diversity is proposed. This antenna has the ability to switch frequency bands and polarization at the same time whereas applying a simple structure. It consists of two concentric circular slots and two tuning stubs on one side of the substrate and a 50 Ω microstrip feed line and two stubs on the other side. The proposed antenna can be switched between two resonant frequencies, 2.4 GHz (WLAN) and 3.5 GHz (Wimax). Furthermore, it can be switched between linear polarization (LP), left-hand circular polarization (LHCP), and right-hand circular polarization (RHCP) at the first frequency band, LHCP and RHCP at the second band. All these capabilities are achieved by applying only five PIN diodes on both sides of the substrate. Simulation and experimental results indicate that the proposed antenna demonstrates a good impedance bandwidth at the two frequency bands and satisfactory radiation pattern in five different states.

Design of a Ring Monopole Dual-Frequency Antenna Fed by Coplanar Waveguide

2012 ◽  
Vol 241-244 ◽  
pp. 2555-2558
Author(s):  
Qi Wang
Keyword(s):  
Wireless Communication ◽  
Frequency Band ◽  
Communication System ◽  
Coplanar Waveguide ◽  
Monopole Antenna ◽  
Experimental Results ◽  
Antenna Design ◽  
Dual Band ◽  
Dual Frequency ◽  
Antenna Structure

A printed ring-shaped monopole antenna fed by coplanar waveguide for use in the dual-band wireless communication system has been presented and investigated. By adding some branch strips inside the ring and changing its size, as well as the further optimization, the proposed antenna could work effectively within the scope of 2.4-2.484GHz and 5.15-5.825GHz frequency band. Practical antenna structure is fabricated. The details of the antenna design and both the theoretical and experimental results are discussed.

scholarly journals DUAL BAND HALF MODE SIW SEMI CIRCULAR CAVITY BACK SLOT ANTENNA

2019 ◽  
Vol 87 ◽  
pp. 7-14 ◽  
Author(s):  
Jagadeesh Dokuparthi ◽  
Alapati Sudhakar
Keyword(s):  
Dual Band ◽  
Slot Antenna ◽  
Circular Cavity

PHOTOINDUCED NONLINEAR OCTUPOLAR POLARIZATION: TRANSIENT AND PERMANENT REGIMES

1996 ◽  
Vol 05 (04) ◽  
pp. 653-670 ◽  
Author(s):  
CÉLINE FIORINI ◽  
JEAN-MICHEL NUNZI ◽  
FABRICE CHARRA ◽  
IFOR D.W. SAMUEL ◽  
JOSEPH ZYSS
Keyword(s):  
Theoretical Analysis ◽  
Second Harmonic ◽  
Experimental Results ◽  
Polar Field ◽  
Rotational Spectrum ◽  
Dual Frequency ◽  
One Dimensional ◽  
Ethyl Violet ◽  
Disperse Red 1 ◽  
Good Agreement

An original poling method using purely optical means and based on a dual-frequency interference process is presented. We show that the coherent superposition of two beams at fundamental and second-harmonic frequencies results in a polar field with an irreducible rotational spectrum containing both a vector and an octupolar component. This enables the method to be applied even to molecules without a permanent dipole such as octupolar molecules. After a theoretical analysis of the process, we describe different experiments aiming at light-induced noncentrosymmetry performed respectively on one-dimensional Disperse Red 1 and octupolar Ethyl Violet molecules. Macroscopic octupolar patterning of the induced order is demonstrated in both transient and permanent regimes. Experimental results show good agreement with theory.

scholarly journals A Multi-Mode Broadband Vibration Energy Harvester Composed of Symmetrically Distributed U-Shaped Cantilever Beams

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 203
Author(s):  
Xiaohua Huang ◽  
Cheng Zhang ◽  
Keren Dai
Keyword(s):  
Energy Harvester ◽  
Low Frequency ◽  
Experimental Results ◽  
Vibration Energy ◽  
Cantilever Beams ◽  
Resonant Frequencies ◽  
Promising Alternative ◽  
Piezoelectric Energy ◽  
Straight Beam ◽  
Resonance Frequencies

Using the piezoelectric effect to harvest energy from surrounding vibrations is a promising alternative solution for powering small electronic devices such as wireless sensors and portable devices. A conventional piezoelectric energy harvester (PEH) can only efficiently collect energy within a small range around the resonance frequency. To realize broadband vibration energy harvesting, the idea of multiple-degrees-of-freedom (DOF) PEH to realize multiple resonant frequencies within a certain range has been recently proposed and some preliminary research has validated its feasibility. Therefore, this paper proposed a multi-DOF wideband PEH based on the frequency interval shortening mechanism to realize five resonance frequencies close enough to each other. The PEH consists of five tip masses, two U-shaped cantilever beams and a straight beam, and tuning of the resonance frequencies is realized by specific parameter design. The electrical characteristics of the PEH are analyzed by simulation and experiment, validating that the PEH can effectively expand the operating bandwidth and collect vibration energy in the low frequency. Experimental results show that the PEH has five low-frequency resonant frequencies, which are 13, 15, 18, 21 and 24 Hz; under the action of 0.5 g acceleration, the maximum output power is 52.2, 49.4, 61.3, 39.2 and 32.1 μW, respectively. In view of the difference between the simulation and the experimental results, this paper conducted an error analysis and revealed that the material parameters and parasitic capacitance are important factors that affect the simulation results. Based on the analysis, the simulation is improved for better agreement with experiments.

Insights into the phenomenon of ‘bubble-free’ electrocatalytic oxygen evolution from water

2021 ◽  
Author(s):  
George Tsekouras ◽  
Richard Terrett ◽  
Zheyin Yu ◽  
Zhenxiang Cheng ◽  
Gerhard F. Swiegers ◽  
...  
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Operating Mechanism ◽  
Evolved Gas ◽  
The Operating Mechanism

Understanding of the operating mechanism of a ‘breathable’ water-splitting electrode, which extracts evolved gas without forming bubbles, is advanced.

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