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Design and Analysis of a Frequency Reconfigurable Microstrip Patch Antenna Switching Between Four Frequency Bands

Design and Analysis of a Frequency Reconfigurable Microstrip Patch Antenna Switching Between Four Frequency Bands

In this paper, a single feed frequency reconfigurable MPA is proposed. The antenna contains two nested patches, i.e., a rectangular patch and an inverted U-shaped patch. Three PIN diodes are placed in the slot present between both patches to provide reconfiguration between four frequency bands of WiFi, WiMAX and GPS. Inset microstrip feed is used to excite the antenna. This type of feed introduces a junction capacitance by introducing a physical notch. By changing the length and width of notch junction capacitance can be changed in order to match impedance of feed line to the patch. This feeding technique has eliminated the need of extra matching network for our antenna. DC bias circuitry is designed by splitting the U-shaped patch into three different parts in order to excite all three diodes independent of each other. λ/ 4 high impedance lines are used to connect diodes to the DC bias which is provided from ground plane through via holes. Bias circuitry is designed without using any lumped element on radiating side of MPA.
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Estimating Range and Relationship of EEG Frequency Bands for Emotion Recognition

Estimating Range and Relationship of EEG Frequency Bands for Emotion Recognition

Relative power prediction phase is concerned with absolute and relative powers of frequency bands. It works on frequency bands extracted in power spectrum analysis phase. First, absolute powers for each EEG frequency band for each of three emotions are premeditated. The absolute powers are calculated for different regions of brain along with combination of electrode pairs using preprocessed EEG dataset as illustrated in Fig. 3. Next, relative power sets are constructed using same EEG dataset for 14 channels and three emotions as shown in Table 2. Thus, four relative power sets corresponding to each frequency band are gained each of size [14*16*3]. The average relative powers of all subjects for each set of frequency bands in each emotion are depicted in Table 2. Delta band is eliminated from analysis as it contains very low frequencies inducing noise.
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A High-Performance Circularly-Polarized Rectenna for Wireless Energy Harvesting at 1.85 and 2.45 GHz
 Frequency Bands

A High-Performance Circularly-Polarized Rectenna for Wireless Energy Harvesting at 1.85 and 2.45 GHz Frequency Bands

Abstract—This paper deals with the design and experiments of a dual-band circularly polarized rectenna at 1.85 and 2.45 GHz. It uses a single antenna and a single RF-to-dc rectifier. The circuit contains a dual-band circularly polarized antenna and a dual-band RF-to-dc rectifier based on a miniaturized 180 ◦ hybrid ring junction. The ring junction is used to independently match the sub- rectifiers at each frequency. The proposed rectenna was experimented with single-tone and multi-tone incident waves. It achieves more than 300 mV and 40% efficiency, across a 4-kΩ resistive load, at very low power density of 1.13 µ W/cm 2 at 1.85 GHz and 1.87 µ W/cm 2 at 2.45 GHz. It also achieves more than 150 mV under the same load condition and in the critical case when receiving only one of the two frequency bands. It is dedicated to harvest RF energy in the GSM 1800 and the 2.45-GHz ISM bands, regardless the polarization angle of the incident waves.
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Compact CPW Fed Switchable UWB Antenna as an Antenna Filter at Narrow-Frequency Bands

Compact CPW Fed Switchable UWB Antenna as an Antenna Filter at Narrow-Frequency Bands

A novel switchable compact coplanar waveguide (CPW) fed UWB antenna having filtering behavior has been presented. Also, miniaturized novel resonators have been incorporated in the partial ground plane to achieve dual notch response. The dual-notch mechanism is also made continuously tunable by introducing capacitors in the miniaturized resonators. It is also shown that the proposed antenna stopbands can also be shifted to our desired frequency bands just by varying the capacitance of the capacitor. The proposed antenna has been simulated in Ansoft HFSS and validated in CST Microwave Studio suite. The proposed antenna is also fabricated, and the measured results are correlated with the simulated ones. Moreover, the proposed antenna possesses a miniaturized size, stable gain, good radiation efficiency, and clean radiation pattern in the passband. The proposed antenna will pave the way for UWB wireless communication applications.
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Materials' Insertion Loss at Three Frequency Bands

Materials' Insertion Loss at Three Frequency Bands

In [3–5], the propagation loss is given for different scenarios and mechanisms. In [6], the effect of metal door on the indoor radio channel received signal has been studied. Three frequency bands namely, (850– 950) MHz, (2.4–2.5) GHz and (5.1–5.3) GHz have been used in the measurement campaign. It has been noticed that the door attenuation is higher than 40 dB at the 5.2 GHz band. In [7], the outdoor-to-indoor propagation loss measurements for broadband wireless access in rural areas are given. In [8], materials’ insertion loss at 2.4, 3.3 and 5.5 GHz bands has been presented.
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THE CHARACTERISTIC FREQUENCY BANDS ANALYSIS OF BRAIN WAVE DURING LEARNING

THE CHARACTERISTIC FREQUENCY BANDS ANALYSIS OF BRAIN WAVE DURING LEARNING

i� th�s �ese��ch�� 50 st���e�ts ���� the de���t�e�t �� c����te� sc�e�ce �e�e teste�� ��� the�� ��������e s�����s ��� the ����c�� �e�s����� �� ����ess����� ����s. b�se�� �� the e�e���� ���st����t��� �� ���� ��������e ch���cte��st�c ��eq�e�c�� ����� ��� ���������� �e���e�s’ ����c�� �e�s����� �����t���� �t est����shes the lei. the e�e���� ���st����t��� �� the teste�� ��������e characteristic frequency band is listed in Table 1. Based on the α, β, θ and δ in Table 1, the ��e���e e�e���� �e�ce�t��e �� the ��eq�e�c�� ����� �� e�ch ���e �s c��c���te�� ���� the �e�e���t ch���cte��st�c ��eq�e�c�� �����s ��e ������ ��t �cc������� t� the e�e���� �e�e� �he� the ���t�c����ts �e�e teste�� ��� the�� “p��������t�� ���� st�t�st�cs” �� the ����ess����� ���sc�����e. the test �es��ts showed that 46 students whose subzone characteristic frequencies of the α and β apparently increased in energy, the frequency of relevant subzones for α is 9Hz to 11Hz and for β is 19Hz to 21Hz, the main frequencies of the subzones for α are α2 and α3 and for β are β7 and β8, and the energy percentage of relevant subzones is apparently higher than that of other s�����es �he� the 50 st���e�ts �e�e �e�s����� ����c����� �� � st�te �� c��sc���s�ess �see t���e 1�. f��� the t���es1�� 2 ���� 3�� �e c�� ���� the ch���cte��st�c ��eq�e�c�� �����s �� the s�����e are the frequency bands at δ1, δ2, θ1 and θ2 at the time when people fall asleep or are in deep s�ee��� �h�ch ��e �����e�t��� �����e�e�t ���� th�se �e�e��te�� ��� ����c�� �e�s����� �� the c�se �� consciousness, and the energy of the frequency bands of α and β is obviously lower than that �cq���e�� �� the c�se �� c��sc���s�ess. the�e���e�� �� ����e� t� c��s���e� the ��������e e�e���� �� the q��c�-��etect��� �e�������� the t�t�� e�e���� �e�ce�t��e �e��te�� t� ��eq�e�c�es �� ���� ���es (α2 and α3, and β7 and β8) is specified as the LEI, and the LEI is used as the basis for teachers t� ����e�st���� the �h��s������c�� st�t�s �� st�������� ����e �� c���e��t��e��� �� �e���e�s.
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Demosaicking Based on Optimization and Projection in Different Frequency Bands

Demosaicking Based on Optimization and Projection in Different Frequency Bands

nance in the low-frequency band, where edge indicators are used as weights to ensure slowly varying chrominance in each object region while high-frequency bands are reconstructed by projection. Using edge indicators helps to avoid smooth- ness in the chrominance across edges. Since the proposed cost function is positive definite quadratic by definition, it is guaranteed to converge to a global minimum. Compari- son of the proposed algorithm with seven demosaicking al- gorithms (both noniterative and iterative) showed that the proposed algorithm works well in producing full-color im- ages with fewer color artifacts in both the edgy and smooth regions.
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Propagation path loss modeling and 
		coverage measurements in urban microcell in millimeter wave frequency 
		bands

Propagation path loss modeling and coverage measurements in urban microcell in millimeter wave frequency bands

In Non-Line-of-Sight (NLOS) cases, the performance of higher frequencies is worse with reliable distances dropping even faster. Most paths are obstructed by objects and buildings. When penetrating obstacles, radio waves are decrease in amplitude. As the radio frequency increases, the rate of attenuation increases. Figure 1 illustrates the effect of higher frequencies having higher attenuation on penetrating obstacles [1].

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Thin Profile Wideband Printed Monopole Antenna for Slim Mobile Handsets Applications

Thin Profile Wideband Printed Monopole Antenna for Slim Mobile Handsets Applications

In this paper, a low profile extremely wideband printed monopole antenna is presented. The pro- posed antenna operates over the LTE700/GSM800/900, GPS L1/GSM1800/1900/UMTS/IMT2100/Wi- Fi/LTE2300/2500, and WiMAX frequency bands based on − 6 dB reflection coefficients. The simulated and measured results are found in good agreement. The configuration of the proposed antenna consists of two strips named as coupling strip and shorted radiating strip at top of the substrate, whereas me- andered parasitic strip at bottom of the substrate. The bottom meandered strip helps in widening the overall operating bands by increasing the capacitance between the main radiating strip and meandered parasitic strip. Due to the capacitive coupling between the top and bottom elements, capacitance comes into the picture. The proposed antenna is elaborated through S -parameters analysis including typical shape parameters, surface current distributions, and radiation performances. Further, study is carried out in the vicinity of the mobile environment and user proximity. SAR is also calculated, and the results are found within the standard limit. The antenna configuration, results and discussion are presented in the following sections.
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Enhanced Detection Performance of Spectrum Monitoring Using Energy Ratio Algorithm for OFDM based Cognitive Radio Networks

Enhanced Detection Performance of Spectrum Monitoring Using Energy Ratio Algorithm for OFDM based Cognitive Radio Networks

spectrum. By making the physical layer (PHY) highly flexible and adaptable, a CR can achieve, the sensing and be aware of its operational environment, and dynamically adjust its radio operating parameters accordingly. The important function of secondary user (SU) is to identify available frequency bands across multiple dimensions like time, space, frequency, angle and code efficiently. Interference between licensed users of that spectrum can be avoided by updating its transmission parameters dynamically. The secondary users identifies, vacant frequency bands under uncertain radio frequency (RF) environment to detect primary users with high probability of detection so that incumbents become active in the band of interest by relying on robust and efficient spectrum sensing (SS) techniques. The Radio Knowledge Representation Language (RKRL) is a language which the cognitive radio uses for knowledge.
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Radio Frequency Identification (RFID)

Radio Frequency Identification (RFID)

Different frequency ranges: RFID tags use different types of frequency bands according to the type of environment its working in and type of application using it. Because radio waves behave differently at different frequencies, it is imperative to choose the right frequency band for the specific application. Frequency is the measurement of radio waves. Basically, four types of frequency bands are used as below,

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Image Super Resolution Using Wavelet Analysis

Image Super Resolution Using Wavelet Analysis

Abstract—The aim of image resolution enhancement is to process a given input low resolution image to make the result more desirable than the original image for a given specific application. In the work, we have proposed an image resolution enhancement technique that generates sharper and high resolution output image. The proposed technique utilizes DWT for decomposing low resolution image in separate sub-bands. Then the above three higher frequency band images are interpolated by the utilization of bi-cubic interpolation. This higher frequency bands generated by stationary wavelet transform of the given input image are then increased into the interpolated higher frequency bands in order to correct the coefficients. The given input image is interpolated in parallel. At last, correctly estimated interpolated higher frequency bands and interpolated input image are mixed by utilizing inverse DWT (IDWT) for getting enhanced output image. After that there is a comparison between the conventional techniques for image enhancement and state-of-the-art image enhancement techniques. One level DWT having Daubechies 9/7 as the wavelet function is utilized to decompose given input image into separate band images. The three higher frequency bands (L-H, H-L, and H-H) has the higher frequency contents of the given input image. In this pro-posed method, bi- cubic interpolation which has increment factor as ‘2’ is then given to higher frequency band images. Due to application of down-sampling in each of the DWT bands there is loss of information in the respective given sub-bands. Hence, SWT is utilized to reduce the losses.
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Correlation for Multi-Frequency Propagation in Urban Environments

Correlation for Multi-Frequency Propagation in Urban Environments

The aim of this paper is to experimentally evaluate the correlation between different frequency bands of shadowing and small-scale fading. The considered frequency bands are the GSM-900, GSM-1800 and UMTS (2100 MHz) bands. Despite not including the newer 4G-LTE frequency band, we expect that the findings in this paper can be generalized to any RF band. Measurements will be conducted in a urban environment to measure the power of the signals transmitted by a base station at different frequencies. The shadowing and small- scale fading parameters for each frequency band will be extracted, and correlation between the different bands will be investigated.
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Development and Demonstration of Graphical User Interface Spectrum Sensing Algorithm using some Wireless Systems in South Africa

Development and Demonstration of Graphical User Interface Spectrum Sensing Algorithm using some Wireless Systems in South Africa

The sequential functionality and other activities involved in the development of SSADA are illustrated in Figure 3. The overall operation of the GUI spectrum sensing algorithm or SSADA is initiated in stage 1 of Figure 3, by choosing a wireless service of interest in the developed graphic user interface program. A hypothetical South Africa frequency allocation table was used for the spectrum sensing and detection demonstration activities using four wireless services’ frequency bands namely radio broadcasting, television broadcasting, mobile telephone and unlicensed, or ISM frequency bands. The four frequency bands were stored in the knowledge base in Figure 2, which serves as the database for the developed SSADA. In addition, the latitude and longitude of the six main cities in South Africa, namely Bloemfontein, Cape Town, Durban, Johannesburg, Port Elizabeth and Pretoria, used as the test sites, were stored in the database to provide information about the location of each of the cities. After providing the preference service and location, the reasoning engine in Figure 2 was updated with this data and the developed SSADA commences rough spectrum sensing by scanning over the entire system bandwidth (B SYS ).
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Power Spectral Density Analysis of Purkinje Cell Tonic and Burst Firing Patterns From a Rat Model of Ataxia and Riluzole Treated

Power Spectral Density Analysis of Purkinje Cell Tonic and Burst Firing Patterns From a Rat Model of Ataxia and Riluzole Treated

Recently, a singnal processing study (Ze’ev et al., 2010) proposed a spectral analysis of the Purkinje neuron output, as a combination of three inherent frequencies observed in its spectrum. These frequencies were due to the calci- um spikes (1-15 Hz), sodium spikes (30-300 Hz) and the switching behavior between silent and firing states (below 1 Hz). The complex behavior of Purkinje cells could be defined by amplitude and frequency modulations of the frequency bands related to the switching behavior, sodium and calcium spikes. The Switching frequency was demon- strated for the first time by Ze’ev et al. in vitro condition (Ze’ev et al., 2010), however in vivo experiments showed similar slow oscillations between 0.039-0.078 Hz (Chen et al., 2009). Slow oscillations of firing and quiescence could be described as an astable mode, versus the known bistable mode in the PCs (Yartsev, Givon-Mayo, Maller, & Don- chin, 2009). A new theory of Purkinje cell function using the terminology of electronic oscillator systems has also been defined which represent astable, bistable and monos- table modalities (Abrams & Zhang, 2011).
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Home used, patient self-managed, brain-computer interface for the management of central neuropathic pain post spinal cord injury: usability study

Home used, patient self-managed, brain-computer interface for the management of central neuropathic pain post spinal cord injury: usability study

The protocol developed in Simulink and LabView [21] was replicated in C++. This was used to enable a large number of users to use the inexpensive systems at the same time (without providing Matlab and LabView li- cence) and to use tablet computers. EEG signal was fil- tered in four frequency bands: 2–30 Hz, theta (4–8 Hz), alpha (9–12 Hz) and higher beta (20–30 Hz) using a 5th order Butterworth filter. Power in each band was calcu- lated over 0.5 s moving average windows and a relative power was calculated by dividing the power of each band (theta, alpha and higher beta) by the EEG power in the 2–30 Hz frequency band. In that way, the EEG power in each frequency band was normalized and expressed as a percentage irrespective of EEG amplitude of an individ- ual user. Relative power during NFB has been constantly compared to the baseline values in corresponding bands. This was reflected by changing colours (from red to green) in the GUI with bars or by changing speed in a GUI with cars.
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Effects Of A Boundary Between HF And LF Bands On Heart Rate Variability Parameters

Effects Of A Boundary Between HF And LF Bands On Heart Rate Variability Parameters

frequencies on the frequency axis (x-axis) that represents the spectral magnitude calculated by the fast FT. Due to data discretization, it is not always possible to assign a precise magnitude to every frequency on a real x-axis, because the number of fast FT values varies based on the number of samples. In the case of a shorter data length, the frequency bin is not in line with an actual frequency as the frequency bin can be derived from the sampling frequency and the resolution of the FT. A range of frequencies between upper and lower bounds always includes the corresponding numbers of the bins. The total number of bins is the same as the number of samples, meaning complex numbers in the frequency domain. The ranges of the frequency bin for the 30 s, 2 m 30 s, and 5 min segments are listed in Table 1-3, and the frequency differences between two consecutive bins were 0.033, 0.07, and 0.003 Hz, respectively. Therefore, the shorter the HRV segment, the large the difference in frequency between two bins. More care must be taken in selecting the frequency bands for the LF and HF bands for an ultrashort-term HRV dataset.
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Case study investigating probabilistic and deterministic sampling methods for developing in-structure response spectra of a fixed base structure model

Case study investigating probabilistic and deterministic sampling methods for developing in-structure response spectra of a fixed base structure model

frequency basis can be misleading when differences in spectral shape are important. For example, the variability calculated according to Eqn. 3 can be very large in frequency regions where the ISRS have steep slopes (Figure 12). Lognormal standard deviations implied by peak spectral accelerations independent of the specific frequency, and at relatively high frequency bands where the ISRS flatten out are typically better estimators of the structural response variability for the purposes of seismic fragility calculations.

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Migration from Microwave to Millimeter-wave for Next Generation Mobile Communication Systems

Migration from Microwave to Millimeter-wave for Next Generation Mobile Communication Systems

The need to meet the continued traffic growth demands led the 3G Partnership Project (3GPP) to begin to develop a new standard for the evolution of GSM/HSPA technology towards a packet-optimized system known as Long Term Evolution (LTE). The goal was thus to produce a new radio access technology with reduced delay with respect to connection establishment and transmission latency, higher user data rates, improved spectral efficiency, increased cell-edge bit-rate, a simplified network architecture, seamless mobility and a reasonable mobile terminal power consumption [12]. One of the ways LTE is able to optimize spectrum allocation is its ability to operate in a wide range of frequency bands and sizes of spectrum allocations in both uplink and downlink. In actual fact, the principle of ‘Spectrum Refarming” make LTE deployable in spectra currently being occupied by older radio access technologies [13].
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Antenna at S-Band as Ground for Array at X-Band in Dual Frequency Antenna at S/X-Bands

Antenna at S-Band as Ground for Array at X-Band in Dual Frequency Antenna at S/X-Bands

A novel configuration for a dual-frequency antenna having a high frequency ratio (1 : 3 . 3) is proposed in this paper. A 2 × 2 antenna array at higher frequency (X-band) is used instead of single patch to achieve high gain. This configuration uses the antenna at lower frequency (S-band) as ground plane for antenna array at higher frequency (X-band) and saves space. It achieves bandwidth of 13.3% at S-band and 6.2% at X-band without any interference between the two bands. It gives gain of 7.5 dBi at 2.5 GHz and 10.5 dBi at 8.2 GHz. It has high isolation of better than 38 dB between the two bands, and the radiation pattern is stable over the bandwidth of the two frequency bands. The antenna is fabricated and tested, and measured results are in reasonable agreement with the simulated ones.
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