F. Malek

A review of wearable antenna

Utilization of wearable textiles in the antenna segment has been seen on the rise due to the recent miniaturization of wireless devices. A wearable antenna is meant to be a part of the clothing used for communication purposes, which includes tracking and navigation, mobile computing and public safety. This literature review intend to disclose this unconventional antenna technology and provides readers with the background of the wearable antenna that would include about specification of the antenna, material for the antenna and analysis that must be done to design proper wearable antennas. All the designs presented are of the recent development in wearable technology.

INVESTIGATION OF THE CHARACTERISTICS OF BARIUM STRONTIUM TITANATE (BST) DIELECTRIC RESONATOR CERAMIC LOADED ON ARRAY ANTENNAS

We investigated a dielectric resonator ceramic microstrip patch antenna. The antenna was formed using barium strontium titanate (BST), which had a dielectric constant of 15. A new approach,i.e., the use of a high temperature dielectric probe kit, was used to determine the dielectric constant of BST. A computer simulation technology (CST) microwave studio was used to simulate the BST array antennas, taking into consideration the dielectric constant. We also measured the gain of the antennas loaded with two-, four, and six-element arrays of the BST antenna and found that the gain of a six-element BST array antenna was enhanced by a gain of about 1.6 dB over the four-element BST array antenna at 2.3 GHz. The impedance bandwidths of these BST array antennas for voltage standing wave ratio (VSWR) < 2 were in the application ranges,i.e., 2.30 to 2.50 GHz, established for Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Local Area Network (WLAN). Compared with the conventional array antenna with the same aperture size, the performance of the antenna obviously was improved, and the design is suitable for array applications, including base stations, for example.

THE USE OF DIELECTRIC MIXTURE EQUATIONS TO ANALYZE THE DIELECTRIC PROPERTIES OF A MIXTURE OF RUBBER TIRE DUST AND RICE HUSKS IN A MICROWAVE ABSORBER

A change in the relative proportions of a mixture of rubber tire dust and rice husks will cause a change in the mixtures electrical permittivity and its ability to absorb electromagnetic energy. An open- ended coaxial probe was used in conjunction with three dielectric mixture equations (the Kraszewski equation, the Landau equation and the Lichtenecker equation) to obtain the dielectric properties of a mixture of rubber tire dust and rice husks (RTDRH) over the frequency range of 7GHz to 13GHz. Lichteneckers equation for dielectrics proved to be a useful practical formulation for determining the efiective permittivity of homogeneous dielectric mixtures. The efiectiveness of these dielectric mixture equations in determining the efiective permittivity of RTDRH was investigated in this study. A newly developed mixture equation was derived based on these dielectric

Effect on source signal condition for pyramidal microwave absorber performance

In designing a microwave absorber for anechoic chamber, there are many condition can affect the performance of microwave absorber. In this work, four conditions are discussed to compare the reflectivity or S11 of the pyramidal microwave absorber. The conditions are different signal source position, areas, angle, and lastly the distance between signal source and pyramidal microwave absorber. These pyramidal microwave absorber are simulated in CST Microwave Studio by using the rice husk as it based material that have dielectric constant, εr = 2.9. This absorber has been designed to operate effectively in frequency range of 1 GHz to 20 GHz

The Analytical Design of a Folded Waveguide Traveling Wave Tube and Small Signal Gain Analysis Using Madey's Theorem

We are developing an analytical model for the design of the folded waveguide traveling wave tube (FWTWT). This analytical model provides the physical view for rapid design optimization of the FWTWT. The design and analysis of the FWTWT using the spatial harmonics method of the TE10 mode of the EM wave are presented. An X-band FWTWT is used to verify this method. The normalized dispersion and beam line equations are used to simplify the design process so that the FWTWT can be designed to operate at any desired frequency. The small signal gain of an FWTWT is calculated by using Madeys theorem. The results of this analysis are compared with the numerical single particle simulation carried out using MATLAB. The results are in excellent agreement. The Madeys theorem can be used to provide a potential indication of the gain magnitude of the FWTWT.

Development of a New Approach for High-Quality Quadrupling Frequency Optical Millimeter-Wave Signal Generation Without Optical Filter

In this paper, we propose a new approach to generate quadrupling-frequency optical millimeter-wave (mm-wave) signal with carrier suppression by using two parallel Mach-Zehnder modulators (MZMs) in Radio-over-flber (RoF) system. Among the numerous properties of this approach, the most important is that a fllterless optical mm-wave at 60GHz with an optical sideband suppression ratio (OSSR) as high as 40dB can be obtained when the extinction ratio of the MZM is 25dB. Simplicity and cost-efiectiveness have made this approach a compelling candidate for future wave-division-multiplexing RoF systems. Theoretical analysis is conducted to suppress the undesired optical sidebands for the high-quality generation of frequency quadrupling mm-wave signal. The simulation results show that a 60GHz mm-wave is generated from a 15GHz radio frequency (RF) oscillator with an OSSR as high as 40dB and an radio frequency spurious suppression ratio (RFSSR) exceeding 35dB without any optical or electrical fllter when the extinction ratio of the MZM is 25dB. Furthermore, the efiect of the non-ideal RF-driven voltage as well as the phase difierence of RF-driven signals applied to the two MZMs on OSSR and RFSSR is discussed and analyzed. Finally, we

Complementary structure of quadruple P-spiral split ring resonator (QPS-SRR) on modified Minkowski patch antenna design

In this work, a modified Minkowski patch antenna had been designed for 2.4 GHz of resonant frequency, fr for wireless local area network (WLAN) application. The proposed complimentary structure of quadruple P-spiral split ring resonator (QPS-SRR) into the patch antenna had been increasing the gain performance. Other parameters that had been considered in this work are return loss, bandwidth, radiation pattern and directivity. This paper also discussed on the effect of single, double and triple sets of quadruple P-shape of the Minkowski patch antenna. This Minkowski patch antenna potentially can be operating the frequency range between 2.362 GHz to 2.427 GHz with a resonant frequency at 2.394 GHz and bandwidth of 65 MHz. The return loss of this Minkowski patch antenna is - 26.072 dB at frequency of 2.4 GHz while the gain is 2.555 dB at frequency of 2.4 GHz.

Microwave FET amplifier stability analysis using Geometrically-Derived Stability Factors

In this paper, the concept of stability in the design of microwave amplifier is re-visited. With the help of EDA tools, the determination of the microwave amplifier stability is simplified through the derivation of Geometrically-Derive Source (μsource) and Load (μload) Stability Factors along with the Rollet Stability Factor (K-Factor). The effects of stabilization elements and layout parasitics i.e. ground inductance towards the amplifiers stability and were discussed. The techniques are then demonstrated with the ATF-50189 E-pHEMT microwave amplifier typical parameters.

A development of Fractal PIFA (planar inverted F antenna) with bandwidth enhancement for mobile phone applications

A novel Fractal planar inverted F antenna (F-PIFA) based on the self affinity design is presented in this paper. The procedure for designing a Fractal Planar Inverted F Antenna is explained and the 2nd iteration of Sierpinski Carpet is chosen to use in mobile phones. The F-PIFA has a total dimension 27mm × 27mm are designed and optimized in order to receive GSM (Global System for Mobile Communication) and UMTS (Universal Mobile Telecommunication System) and HiperLAN (HigH Performance Radio LAN with the frequency range from 1710 MHz to 2170 MHz, 1885 to 2200 MHz for 3G and 4800MHz to 5800MHz for HiperLAN respectively. The antenna achieved the GSM, UMTS and HiperLan frequency with −6dB return loss and has almost omnidirectional radiation pattern. This antenna has been tested using mobile phone model and all the performance met the criteria for a mobile phone application.

Reflection loss performance of hexagonal base pyramid microwave absorber using different agricultural waste material

Hexagonal base pyramid microwave absorber is the new design of microwave absorber. In this work, two sub-shapes are considered to compare it reflection loss performance. The shapes are hexagonal and truncated hexagonal base pyramid. Three sample of agricultural waste are used that is rice husk, rice straw and banana leaves. Before that, free space measurement technique is applied to define the dielectric constant and tangent loss of the material used. These microwave absorbers have been designed to operate effectively between the frequencies of 1 GHz and 20 GHz.