ملخص البحث :

This paper presents, new compact and multiband frequency reconfigurable planar inverted-F antenna (PIFA). The antenna is designed and optimized to cover mobile application devices like GPS, WLAN/Wi-Fi, WiMAX, 4G LTE, UWB, and satellite applications. The frequency reconfigurability is obtained by using only a single RF switch (PIN diode) for changing the operating frequency. The antenna dimensions are 45.6 x 39.6 x 1.6 mm3 printed on an FR-4 epoxy substrate with relative dielectric constant εr = 4.3, loss tangent tan (δ) =0.002 and 50 Ω coaxial feed line. The proposed antenna has two patches connected by a single PIN diode. The antenna introduces nine resonant frequencies under (S11 ≤ -10 dB) which are: 0.980 GHz, 3.392 GHz, 3.924 GHz, 4.554 GHz, 5.82 GHz, 6.81 GHz, 7.305 GHz, 8 GHz and 8.105 GHz in the ON and OFF states of the PIN diode which are applicable to cover GSM900, WLAN/Wi-Fi, WiMAX, 4G LTE, UWB, and satellite systems. The obtained maximum simulated gain is 8.45 dB at 6.81 GHz. The lowest return loss is obtained to be -42 dB at 5.854 GHz. Detailed simulation and measurement results are explored and studied in this research. The CST software is used to simulate and optimize the proposed PIFA antenna. The proposed antenna has been fabricated and produced a good agreement with the simulation results.

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ملخص البحث :

This paper presents, new compact and multiband frequency reconfigurable antenna for cognitive radio applications. A UWB sensing and reconfigurable communicating antennas are contained at the same substrate, where the UWB sensing antenna is an elliptical printed monopole antenna operates on frequency band from (2.65-22.112) GHz which can cover the UWB frequency band from 3.1 to 10.6 GHz, while the communicating antenna is an inverted-L frequency reconfigurable antenna operates on three bands of 1.49 GHz, 5.58 GHz, and 5.6 GHz under (S11 ≤ -10 dB) with a fractional bandwidth of 5.872%, 6.02%, and 6.05% respectively. The proposed antenna used to operate in two modes one for cognitive radio applications to cover WLAN applications at 5.5 GHz and 5.6 GHz and the second mode for wireless Ethernet, GPS synchronization, and Internet of Things that Matter (IoTtM) at 1.49 GHz. The frequency reconfigurability is obtained by using only a single RF switch (PIN diode) for changing the operating frequency. The antenna overall dimensions are 72 x 36 x 1.6 mm3 printed on an FR-4 epoxy substrate of 4.3 relative-permittivity, loss tangent tan (δ) = 0.002 and 50 Ω micro stripline feed. The obtained simulated gain is ranging from 1.35 to 4.132 dBi. The S11 and isolation (S12) between the two antennas are under -20 dB and -17 dB respectively at the resonant frequencies.

ملخص البحث :

This paper presents, compact multiband frequency reconfigurable 3x1 MIMO antenna for cognitive radio applications. The antenna comprises 3-elements reconfigurable MIMO antenna and single element UWB sensing antenna. The frequency reconfigurability range under (S11 ≤ -10 dB) from 7-14.8 GHz using single PIN diode, while the UWB frequency range from 2.597-23.08 GHz. The antenna is designed and optimized to cover such wireless applications such as WiMAX, international telecommunication union (ITU), satellite, and broadband applications. The antenna is optimized using a Genetic Algorithm to operate in the MIMO and cognitive radio systems. The antenna dimensions for 3-elements MIMO antenna are 55 x 65 x 1.6 mm3 printed on an FR-4 epoxy substrate with relative dielectric constant εr = 4.3, loss tangent tan (δ) =0.002 and 50 Ω microstrip feed line. The obtained simulated gain is ranging from 2.8-8.25 dB and the maximum simulated gain is 8.25 dB at 8.5 GHz. The return loss, Envelope Correlation Coefficient ECC, and Isolation are obtained to be less than -25 dB, less than 0.018, and less than -17 dB respectively. Detailed simulation results are explored and studied in this research. The CST software is used to simulate and optimize the proposed antenna.

ملخص البحث :

This paper presents a compact multi-band frequency reconfigurable MIMO antenna for wireless applications. The antenna is designed and optimized to cover such wireless applications like satellite, Radar, and broadband applications. The frequency reconfigurability is obtained by using only one RF switch (PIN diode) for changing the operating frequency at ON/OFF states of the PIN diode. The dimensions of the 4-Elements MIMO antenna are 45x45x1.6 mm3 printed on an FR-4 epoxy substrate with relative dielectric constant εr = 4.3, loss tangent tan (δ) = 0.002 and 50 Ω microstrip feed line. The proposed antenna has two patch side arms connected by a single PIN diode. The antenna introduces three resonant frequencies under (S11 ≤ -10 dB) which are: 12 GHz, 13.95 GHz, and 14.91 GHz in the ON-state and OFF-state of the PIN diode with a fractional bandwidth of 1.85%, 6.66%, and 4.15 % respectively. The obtained simulated gain is ranging from 8 to 10.45 dB and the maximum simulated gain is 10.45 dB at 17 GHz. The lowest return loss is obtained to be (-50) dB at 13.95 GHz. Detailed simulation results are explored and studied in this research. The return loss, Envelope Correlation Coefficient ECC, and Isolation are obtained to be less than -20 dB, less than 0.02, and less than -17 dB respectively. The CST software is used to design and optimize the proposed MIMO antenna.

ملخص البحث :

The outbreak of Corona disease, or the so-called Covid-19, has affected the course of human life. Detecting this disease early reduces the risk of spreading the disease. Thus, get rid of this epidemic sooner. In this paper, a system is created that helps to identify and detect Covid-19 disease through X-ray radiation. GoogLeNet, ResNet-101, Inception v3 network, and DAG3Net that are used for comparison purposes. Good results have been obtained in detecting Covid-19 disease, where the DAG3Net produces diagnostic (validation, training, testing and overall) accuracies of (96.15%, 94.34%, 96.75% and 96.58%) respectively, while the GoogLeNet, ResNet-101, and Inception v3 network are produced (98.08%, 100%, 99.59% and 99.72%) respectively.

ملخص البحث :

A new compact frequency tuning antenna with a single element and two polarized elements for Ultra-Wideband Multi Input Multi Output (UWB-MIMO) wireless applications is designed and analyzed using the CST package. The proposed antenna supports four PIN diodes for frequency tuning and controls the frequency band from UWB band to narrowband through their ON/OFF states. The proposed 2-elements structure is designed using FR4 substrate with overall dimensions of (30x60x1.6) mm3, the relative permittivity of 4.3, microstrip line feed with 50 Ω, and the antenna comprises patch element with an elliptical-shaped of radii of (10, 8) mm, two stubs with equal dimensions of (10x4) mm2 connected to the microstrip line feed by PIN diodes and half elliptical GND plane with radii of (15, 7) mm. The proposed antenna operates with three frequencies with bands under (S11 ≤ -10 dB) from (3-9.65) GHz, (6.13-7.21) GHz, and (5.45-7.6) GHz according to the PIN diodes states. These bands can be used to cover UWB, Satellite, and WiMAX applications. The maximum gain is 4.2 dB and the lowest return loss is -46 dB at 6.68 GHz. The performances behind this design are less than 0.022, around 10, less than -20 dB for the Envelope-Correlation-Coefficient (ECC), Diversity-Gain (DV), and Isolation respectively.

ملخص البحث :

This article presents design and simulation of a new compact four-element dual-band MIMO frequency reconfigurable antenna that can be reconfigured for WiMAX and LTE applications. The antenna includes four elements at the same FR4 substrate with an optimized overall size of 65x65x1.6 mm3 and an optimized partial GND plane of 30x11.125 mm2. The reconfiguration rate is between 2.41 and 3.99 GHz that can cover the WiMAX and LTE wireless devices by applying just one RF (PIN) switch to change the operating frequency. The antenna operates on the two states of the PIN diode under its two states ON and OFF with (2.7 GHz, and 2.8 GHz) resonant frequencies respectively. The proposed antenna produces acceptable simulation results for the MIMO system by achieving gain from (3-7.2) dBi, less than -14.5 dB coupling effect, less than 0.28 envelope correlation coefficient, and diversity gain range from 8.4-10.