High Gain UWB Four Elements Antenna Array for C-Band and X-Band Application

The C-band is allocated for commercial telecommunications via satellites. Amateur satellite operations in the frequency range 5.830 to 5.850 GHz for down-links and 5.650 to 5.670 GHz for up-links are allowed by International Telecommunication Union. The X-band is used for terrestrial broadband communication, radar applications, and portions of the X-band are assigned for deep space telecommunications. In this paper, a design of 4 × 1 Ultra Wide Band (UWB) antenna array for C-band and X-band applications is introduced. Metamaterial sixteen-unit cells are incorporated into each antenna element for radiation characteristics enhancement purposes. Permeability and permittivity of metamaterial unit cells are obtained all over the operating bandwidth. UWB unequal power divider is used to feed the proposed four elements antenna array based on Chebyshev excitation method. The proposed antenna has a suitable 3 dB beam width and gains all over the operating bandwidth which extends from 5.6 GHz to 10.9 GHz. The proposed antenna covers 60% and 72.5% of the C-band and X-band, respectively. The proposed antenna is fabricated, measured, and good agreement is obtained between simulated and measured results. The obtained performance ensures the suitability of the proposed antenna array for C-band and X-band applications.

Ultra-Wideband Log Periodic Dipole Antenna (LPDA) for Wireless Communication Applications

This paper proposes a printed log-periodic dipole antenna (LPDA) for ultra wide bandwidth (UWB) applications. The antenna comprises of cascading four U shaped elements of different line lengths with balun circuit to improve the antenna impedance matching. The proposed antenna dimensions are 50 × 50 mm2 with FR4 substrate thickness 0.8 mm. Full-wave EM solver HFSS (High Frequency Structure Simulator) is used for modeling the proposed antenna. The pulse distortion is verified by the measured the proposed antenna performance with virtually steady group delay. The simulation and experimental results show that the proposed antenna exhibits good impedance matching, stable radiation patterns throughout the whole operating frequency bands, acceptable gain and stable group delay over the entire operating band. An UWB extended from 1.85 GHz to 11 GHz is obtained, and the average antenna gain is about 5.5 dBi over the operating band with peak gain around 6.5 dBi and 70% average radiation efficiency.

Investigation and Comparison of 2.4 GHz Wearable Antennas on Three Textile Substrates and Its Performance Characteristics

In this paper, two different methods were used for investigating the RF characteristics of three types of textile materials. Goch, Jeans and Leather substrates were studied. A microstrip ring resonator method and DAK (Dielectric Assessment Kit) method were used. Bluetooth antennas were designed and fabricated using these substrates. The results were compared for the two methods. The bending effect of these antennas on its impedance characteristics due to human body movements was also studied. Finally, all antennas were simulated by CST simulator version 2016, fabricated using folded cupper and measured by Agilent 8719ES VNA. The measured results agree well with the simulated results.

Reconfigurable 3/6 dB Novel Branch Line Coupler

In this paper, a new idea of reconfigurable 3/6 dB branch line coupler is proposed. The proposed coupler is tuned through a simple open and short circuit at the coupler’s branches’ edges. At the short edges case, a 3 dB branch line coupler is obtained. In this case, the coupler’s branches are considered as microstrip transmission lines with 0.3 mm slot width which is etched in each coupler’s branch. At the open edges case, the coupler’s branches are considered as asymmetric coupled microstrip lines. In this case, a 6 dB branch line coupler is obtained. Both CST and IE3D simulators are used to optimize the reconfigurable 3/6 dB branch line coupler dimensions. As a prototypes, two BLCs are designed, analyzed and tested at the “on” and “off” states at 2.5 GHz. The measured S-parameters confirm the proposed concept of the reconfigurable 3/6 dB branch line coupler.

A 2.4 GHz Switched Beam Antenna for Indoor Applications Using Angle of Arrival Estimation

This study introduces a new design of planar antenna array for ISM band applications at 2.4 GHz. This prototype is switched beam antenna, namely planar antenna with four meandered slotted triangular elements (PAFMSTE), which is proposed for wireless indoor applications. The Base Station (BS) equipped with this planar antenna is preferred to be at the center position on the room ceiling to cover all sectors of the room. It is designed to use four directional triangular elements arranged to form a square planar antenna array. The PAFMSTE is used to obtain optimal directivity in four directions in azimuth plane with 3 dB beamwidth of 90°at a specific orientation of 30°in elevation plane. Switched parasitic technique is used to enable PAFMSTE to steer a directional beam through four locations by using four PIN diodes switches. The High Frequency Structure Simulator (HFSS) is used as an efficient simulation tool to optimize the performance of the PAFMSTE antenna. The fabrication and measurements of the PAFMSTE antenna are introduced. The proposed antenna enable radio positioning via Angle of Arrival (AOA) information collected from nearby devices. Then, the Cramér-Rao Bound (CRB) is presented for AOA estimation using identically and equally spaced antenna elements. The CRB depends on the directivity, where the maximum values of CRB are 1.35 × 10-3 and 8 × 10-3 at HPBW of 60° and 90°, respectively.

Pencil Beam Grid Antenna Array for Hyperthermia Breast Cancer Treatment System

In this paper, efficient, high gain and pencil beam grid antenna array is proposed for hyperthermia breast cancer therapy system. The proposed antenna bandwidth extends from 4.8 GHz to 4.9 GHz at resonant frequency of 4.86 GHz. This frequency band has been reported for the breast cancer hyperthermia therapy. The grid long and short sides are responsible for the undesired cross-polarized radiation and desired copolarized radiation, respectively. The unsuitability of the conventional grid antenna array is ensured by investigating its radiation properties. The proposed grid antenna array short side width is varied and its long side width is kept wide as possible to enhance the radiation properties and to reduce the losses. Also, a reflector has been used for gain enhancement purpose. The proposed grid antenna array achieves side lobe level and 3 dB beam width of —27.9 dB and 25.9° for the E-plane and —27.9 dB and 26.3° for the H-plane, respectively. The breast phantom is irradiated by both proposed and conventional grid antenna arrays for 10 minutes. The proposed grid antenna array achieves 8°C temperature increase within the breast phantom area compared to 2°C temperature increase for conventional one. The proposed grid antenna array is highly efficient, high gain and light weight, and it has a very suitable radiation property for hyperthermia breast cancer therapy.

Beamforming and Angle-of-Arrival Estimation of Square Planar Antenna Array

This paper presents a dual-band planar antenna array for ISM band applications (2.4 GHz and 2.45 GHz). This antenna is proposed for indoor applications and enables adaptive beamforming and angle of arrival (AOA) estimation. An adaptive beamforming algorithm is applied for a planar antenna array, which is able to steer its main beam and nulls in azimuth and elevation planes over a wide frequency band. Planar antenna array operates as a spatial filter in 3D space, processing the received signals with weighting schemes. A planar antenna array is designed for AOA estimation in azimuth and elevation planes by using MUltiple SIgnal Classification (MUSIC) based on subspace algorithm. The Base Station (BS) equipped with this planar antenna is preferred to be at the center position on the room ceiling to cover all sectors of the room. It is designed to use four directional triangular elements arranged to form a square planar antenna array. Planar antenna with four elliptical slotted triangular elements (PAFESTE) is used to obtain optimal directivity in four directions in azimuth plane with specific orientation of 30? in elevation plane. It is characterized by half power beamwidth in elevation plane of about 60? and half power beamwidth in azimuth plane of about 90?.