Azeemuddin Syed

Miniature slotted RFID tag antenna for metallic objects

Designing RFID tag antenna for metallic objects is a challenging task as antenna parameters are highly affected by metallic surface. This paper presents a miniaturized slotted RFID tag antenna with overall dimensions of 33 mm × 16 mm × 3.2 mm for metallic objects. The proposed design contains two coplanar metallic patches which are electrically connected to the ground plane through a copper via. Multiple slots are created on metallic patches which help in improving overall antenna inductance. A non-connected metallic plate is present between the ground and the patches. The proposed antenna design is simulated and fabricated, and its parameters are analyzed. It is concluded that this design can be reused for different tag chips having different input impedances simply by varying slot length without changing any other antenna dimensions. The read range of the proposed design, when the tag antenna is mounted on the metallic surface, is approximately 80 cm.

Measurement of position (angle) information of BLDC motor for commutation used for e-bike

Brushless Direct Current (BLDC) Motors are gaining rapid popularity and are used in many applications. One such application is automobiles where the BLDC motors are used to run the electric vehicles such as e-bikes and e-cars. For commutating a BLDC Motor, Trapezoidal Algorithm is used ubiquitously. But Trapezoidal Algorithm has limitations such as utilizing the motors efficiency to the maximum. In theory, it is known that the sinusoidal and FOC algorithms can overcome the limitations of Trapezoidal commutation. In order to implement sinusoidal and FOC algorithms, the exact position (angle) is needed. In this paper, measurement of the position (angle) information along with a new sensor drive scheme of BLDC Motor for commutation using Magnetic Rotary Encoder AS5048A fabricated at ams is presented.

Performance Boost of Spiral Inductors With Thickness-Controlled Domain-Patterned Permalloy

In CMOS radio frequency integrated circuits, inductors are a barrier in achieving better monolithic solutions because of the large area occupied and the associated parasitics. For better performance of on-chip inductors, soft magnetic materials are incorporated with them. In an earlier work, it was shown that by tailoring the shape and size of the permalloy patterns, formation of magnetic domains can be controlled. When such domain patterns are incorporated with inductors, they have varied effects on inductor performance. In this paper, it is demonstrated that by depositing 60 nm thick domain-controlled permalloy patterns, better performance of inductors can be obtained at higher frequencies (>5 GHz). About 2× increment in inductance and 7× increment in quality factor is obtained at frequencies >5 GHz by incorporating appropriate domain-controlled permalloy patterns with inductors.

A Web-Based Virtual Laboratory for Electromagnetic Theory

Electromagnetic theory is one of the core subjects in Electrical/Electronics and Communication Engineering. It involves many concepts that are abstract and difficult to visualize, hence learning or teaching it is a challenge. This paper presents a web based virtual laboratory for electromagnetic theory course taught at undergraduate level, which can be used as a didactic tool by teachers and as a self learning tool by students. A set of ten topics have been chosen which broadly cover the basics of electromagnetic theory. The laboratory helps the students to visualize and experiment with abstract concepts of electromagnetic theory. It also contains theory supporting the experiment to aid teaching-learning process. The laboratory contains evaluation sections to assess students understanding before and after performing virtual experiment. Assessment of the virtual lab done by evaluating students and feedback about the laboratory collected from both teachers and students are presented.

Role of dimension size of patterned permalloy films in high frequency applications

Ferromagnetic materials have been extensively used into on-chip passive devices to improve device performance at radio frequencies (RF). A lot of work is in progress to boost up the frequency response of permalloy material in order to incorporate it with RF Inductors. One of them is control of domain dynamics. Therefore to control the domain dynamics it is important to know the factors effecting the high frequency performance. In this work, Double and Single domain permalloy bars with varying dimension sizes have been incorporated with transmission lines. The simulation and measured results show that dimension size of these patterned permalloy films play a crucial role in boosting up the frequency response. It is also observed that a particular size of permalloy bars can be used for a specific range of frequencies. As the dimension of the bar decreases maintaining same domain pattern, the frequency to which it responds can be increased. Finally, effect of surface topography on domain structures and corresponding dynamic processes is also discussed.

Performance Evaluation of Integrated Semiconductor Ring Laser Gyroscope

We present a mathematical analysis and comparison of the performance of integrated on-chip semiconductor ring laser gyroscope (SRLG) fabricated using GaAs/AlGaAs and InP/InGaAsP technologies. The performance parameters of the gyro are modeled in terms of fundamental material, waveguide, and resonator parameters. In addition to this, influence of phenomena specific to semiconductor lasers such as nonlinear coupling, spatial hole burning, gain grating formation, and carrier induced index change on the gyro performance is also included. The analysis helps in identifying critical parameters, which must be optimized to improve the gyro performance.Best achievable performance of integrated SRLG is calculated, and design modifications are suggested to enhance it for high-performance military applications.

Rotation Sensing Through Semiconductor Ring Laser Gyro : Analyzed and Explained Using Photon Lifetime

This paper explains the importance of the role played by photon lifetime in the generation of terminal voltage across Semiconductor Ring Laser Gyroscope (SRLG). This terminal voltage can be used for direct measurement of rotation rate.

Permalloy Magnetic Domain Control For Radio Frequency Applications

Investigation of relationship between permalloy film geometries and domain patterns through simulation and fabrication is presented in this paper. As a result domain controlled magnetic material is developed for high frequency circuits and passive components viz. inductors. Control of domain patterns was acheived by varying the film dimensions including the thicknesses with no external magnetic field applied.

Non-linearity between frequency bands and segmentations of meander antennas

Fractal based approach uses self-similar design to build compact multi-band or wideband antennas. But the inherent geometrical complexity of fractal design makes it difficult to apply large number of iterations on wire antennas like monopole and dipole. Therefore we have proposed simple designs of meander antenna using the segmentation approach which requires only first iteration of fractal. We have also studied and observed the relationship between segmentation and frequency bands. It has been observed that the operational bands increase non-linearly with the increase in segmentation.

Mathematical model of nonlinear coupling and its effect on rotation sensitivity of semiconductor ring laser gyroscope

The moving population inversion gratings formed due to spatial hole burning inside a semiconductor ring laser gyroscope causes nonlinear coupling of the counter-traveling modes. We mathematically demonstrate this phenomenon using Perturbation Theory and calculate the limit imposed by it on the sensitivity of inertial rotation.