The study and exploration of massive multiple-input multiple-output (MMIMO) and millimeter-wave wireless access technology has been spurred by a shortage of bandwidth in the wireless communication sector. Massive MIMO, which combines antennas at the transmitter and receiver, is a key enabler technology for next-generation networks to enable exceptional spectrum and energy efficiency with simple processing techniques. For massive MIMOs, the lower band microwave or millimeter-wave band and the antenna are impeccably combined with RF transceivers. As a result, the 5G wireless communication antenna differs from traditional antennas in many ways. A new concept of the MIMO tri-band hexagonal antenna array is being introduced for next-generation cellular networks. With a total scaling dimension of 150 × 75 mm2, the structure consists of multiple hexagonal fractal antenna components at different corners of the patch. The radiating patch resonates at 2.55–2.75, 3.45–3.7, and 5.65–6.05 GHz (FR1 band) for better return loss (S11) of more than 15 dB in all three operating bands. The coplanar waveguide (CPW) feeding technique and defective ground structure in the ground plane have been employed for effective impedance matching. The deviation of the main lobe of the radiation pattern is achieved using a two-element microstrip Taylor antenna array with series feeding, which also boosts the antenna array’s bandwidth and minimizes sidelobe. The proposed antenna is designed, simulated, and tested in far-field radiating conditions and generates tri-band S-parameters with sufficient separation and high-quality double-polarized radiation. The fabrication and testing of MIMO antennas were completed, where the measurement results matched the simulation results. In addition, the 5G smartphone antenna system requires a new, lightweight phased microwave antenna (μ-wave) with wide bandwidth and a fire extender. Because of its decent performance and compact architectures, the proposed smartphone antenna array architecture is a better entrant for upcoming 5G cellular implementations.
In this paper, a compact bandpass filter with improved band stop and band pass characteristics for wireless applications is built with four internal conductive poles in a single resonating cavity, which adds novel quad-resonating modes to the realization of band pass filter. This paper covers the design and testing of the S-band combline coaxial cavity filter which is beneficial in efficient filtering functions in wireless communication system design. The metallic cavity high Q coaxial resonators have the advantages of narrowband, low loss, better selectivity and high potential for power handling, as compared to microstrip filter in the application to determine the quality factor of motor oils. Furthermore, the tuning of coupling screws in the combline filter allows in frequency and bandwidth adjustments. An impedance bandwidth of 500 MHz (fractional bandwidth of 12.8%) has been achieved with an insertion loss of less than 2.5 dB and return loss of 18 dB at the resonant frequency. Four-pole resonating cavity filters have been developed with the center frequency of 4.5 GHz. Insert loss at 0 dB and estimated bandwidth at 850 MHz and a quality factor of 4.3 for the band pass frequencies between 4 and 8 GHz is seen in the simulated result.
Mammography is the most efficient technique for detecting and diagnosing breast cancer. Clusters of microcalcifications have been mainly targeted as a reliable early sign of breast cancer and their earliest detection is essential to reduce the probability of mortality rate. Since the size of microcalcifications is very tiny and may be overlooked by the observing radiologist, we have developed a Computer Aided Diagnosis system for automatic and accurate cluster detection. A three-phased novel approach is presented in this paper. Firstly, regions of interest that corresponds to microcalcifications are identified. This can be achieved by analyzing the bandpass coefficients of the mammogram image. The suspicious regions are passed to the second phase, in which the nodular structured microcalcifications are detected based on eigenvalues of second order partial derivatives of the image and microcalcification pixels are segmented out by exploiting the foveal segmentation in multiscale analysis. Finally, by combining the responses coming out from the second order partial derivatives and the foveal method, potential microcalcifications are detected.The detection performance of the proposed method has been evaluated by using 370 mammograms. The detection method has a TP ratio of 97.76 % with 0.68 false positives per image. We have examined the performance of our computerized scheme using free-response operating characteristics curve.
A novel multi-band clover leaf-shaped fractal antenna with integrated filtering to reduce higher order harmonics has been proposed. Existing microstrip filtering antennas endure limited gain, narrow impedance bandwidth, and undesired frequency radiations. The proposed antenna is designated to operate simultaneously in following operating bands: 3.35-3.6 GHz for WiMAX, 5.156-5.825 GHz for WLAN, 5.7-6.4 GHz for Intelligent Transport Systems (ITS), and 7.7-8.5 GHz for ITU-R applications. The proposed patch is realized by combining two semi-fractal ring microstrip patches like the geometry of a three-leaf clover with dual-layered stepped impedance resonator (SIR) integrated at bottom layer of the second substrate. The SIR bandpass filter exhibits odd and even modes suppresses higher order harmonics and undesired radiations. An aperture coupled feeding in the proposed patch offers better bandwidth and impedance matching. The number of iterations is increased to get the desired multiband characteristics. The proposed microstrip fractal antenna has the geometrical dimensions of 50 Â 50 Â 2 mm 3 . It is observed that both the simulated and measured results offers peak gain of >5 dBi and better return loss (S 11 ), that is, 3.3-3.6-GHz band offers S 11 of À33.73 dB, 5.15-5.825-GHz band offers S 11 of À36.69 dB, and 5.795-6.4-GHz band shows the S 11 of À36.25 dB, and for 7.725-8.5 GHz, the return loss is À33.209 dB.Harmonics at 6.42 GHz (1.8f 0 ), 7.37 GHz (1.5f 0 ), and 9.04 GHz (1.73f 0 ) has been suppressed and shows linear polarization in the WLAN band and circular polarization in the ITU-R and WiMAX bands.
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