Relays, Working principle of relay,

            Introduction:

An electrical relay is a switch which is under the control of another circuit. A classic example of an electrical relay is the system used to start a car. When someone turns an ignition key, the ignition does not interact directly with the car battery.

Grid Substation, Introduction, Grid station and National Grid substations

Grid Substation                                                            

  Introduction:

A grid substation is part of the electricity grid system -i.e. part of the transmission system. In the Bangladesh, this involves voltage levels of 400 kV, 230 kV, 132KV,66,11KV,  KV,440V,220V132 kV.Transmission of power occurs through the power distribution grid.

Recommendation for Future Work ,Results Validated By Theoretical Modeling and Development of Algorithm

Recommendation for Future Work:

          In the whole research work, attention was paid to simulate all the structures by commercial EM software Zeland IE3D. Investigations need to be justified experimentally by VNA and compared with simulated results.

Motivation, Reasoning and the Proposed Proposition of EBG structures and Application of Dumbbell shaped EBGS as BPF

Motivation, Reasoning and the Proposed Proposition of EBG structures

From the intensive literature survey it is clear that the inclusion of EBGSs / dumbbell shaped EBGSs improve the performance of microwave components and devices significantly. From the performance of novel 2-D EBG structures for microstrip lines it is obvious that the performance is hindered by the optimized value of FF.

Realization of Band Pass Filter (BPF) and Non-uniform EBGS

 Realization of Band Pass Filter (BPF)

Each type of filters has different type of applications in the field of microwave communication system. There is a well defined formula deduced from the Bragg’s condition for circular shaped EBGS.

Performance of uniform circular PBGS Assisted BPF, Performance of reference BPF, Performance of BPF on 2-D array of uniform circular PBGSs, Performance of BPF on dense 2-D array of uniform circular PBGSs, Performance of BPF with three line uniform circular PBGSs, Performance of BPF with uniform circular PBGSs under two extreme 50 ohm lines, Performance of BPF with uniform circular PBGSs under all the lines Performance of BPF with uniform circular PBGSs under all the line

    Performance of uniform circular PBGS Assisted BPF

Theoretical results are produced for different geometries of uniform circular PBGS assisted BPF. To see the effect of uniform circular PBGS in harmonic suppression the performance of reference BPF is shown. Finally the insertion loss performances of a standard BPF and uniform circular PBGS assisted BPF are shown to compare the results.

Simple T-line and its performance, S-Parameter Performance of a microstrip T-line, Design of uniform circular PBGSs for Harmonic Suppression, Standard BPF, BPF on 2-D array of uniform circular PBGSs, BPF with dense 2-D uniform circular PBGSs, BPF with PBGSs under 50-ohm and central coupled lines

    Simple T-line and its performance:

T-line is just a line with a defined length and width on the upper surface of the substrate which is created by removing copper coating from the surface except the desired region. The figure is shown below where the blue region is a typical T-line whose length is 100 mm and width is 2.2642 mm (calculated by PCAAD for 50Ω microstrip T-line where dielectric constant of the substrate is 2.45 and thickness is 31 mils).

Corrugated Surface and Metal Pad or High-Impedance Surface

Corrugated Surface

A corrugated surface is a metal slab into which a series of vertical slots are cut. The slots are narrow so that many of them fit within one wavelength across the slab. Each slot can be regarded as a parallel plate transmission line, running down into the slab, and shorted at the bottom.

Microwave Filter design, Applications to BPF ,Application to LPF, Application to dual stopband filter, Band-pass filters

Microwave Filter design

              There is a vast amount of published literature on the design of microwave filters from which some are highly mathematical. Fortunately there are some relatively straight forward procedures which enable us to design certain useful classes of microwave filters. Filter designing using the image parameter method consist of a cascade of simpler two-port filter sections to provide the desired cutoff frequencies and attenuation characteristics but do not allow the specification of a frequency response over the complete operating range.

Microwave Filters,Lumped - element LC filters , Planar filters, Coaxial filters, Cavity filters, Dielectric filters and Electro acoustic filters

Lumped - element LC filters

An LC tank circuit consisting of parallel or series inductors and capacitors is a best example of a simplest resonator structure. These LC tank circuits have the advantage of being very compact & small in size, but having the low quality factor of the resonators which leads to relatively poor performance. 

Figure: Commercial photograph of Lumped-element LC filters.

Introduction, Microwave filters, Filter and There are mainly four types of filters with respect to functions

  Microwave filters

   Introduction

          A filter is a two-port network used to control the frequency response at a certain pointin an RF or microwave system by providing transmission at frequencies within the passbandof the filter and attenuation in the stopband of the filter.

Microwave filters represent a class of electronic filter design to operate on signals in the MHz to GHz frequency ranges. This frequency range is the range used by most broadcast radio, television, wireless communications like Cell phone, Wi-Fi, Wi-Max and the most radio frequency and microwave devices will include some kinds of filtering on the signals transmitted or received.

Theoretical Background and Microwave Transmission lines Theories

 Introduction:

Recently EBGSs have occupied significant portions of microwave engineering literature to enhance the performance of many microwave devices and components. The nomenclature EBG is actually used in the optical communication. Recently they are scaled down to RF engineering. They are very old concepts in terms of periodic structures. EBG structures are periodic in nature.

Application of microwave engineering, Microwave Transmission lines and Microwave filters

            In microwave engineering high frequency and short wavelength make unique opportunities for the microwave systems. This is because of following consideration:

§  Antenna gain is proportion to the electrical size of the antenna. At higher frequencies, more antenna gain is therefore possible for a given physical antenna size, which has important consequences for implementing miniaturized microwave system.

The Biased p-n Junction

     An externally applied potential will alter the potential difference between the p- and n-regions. This in turn will modify the flow of majority carriers, so that the junction can be used as a “gate”. If the junction is forward biased by applying a positive voltage V to the p-region Fig. , its potential is increased with respect to the n-region, so that an electric field is produced in a direction opposite to that of the built-in field.

THE IGFET/MOSFET

The second (and most important) family of FETs are those known under the general title of IGFET or MOSFET. In these FETs, the gate terminal is insulated from the semiconductor body by a very thin layer of silicon dioxide, hence the title ‘Insulated Gate Field Effect Transistor,’ or IGFET. Also, the devices generally use a ‘Metal-Oxide Silicon’ semiconductor material in their construction, hence the alternative title of MOSFET.

Multiple Impulse Method (SIM/MIM)

       The Multiple Impulse Method is the most advanced cable fault prelocation method available.

Every cable fault that is either a high resistive or intermittent fault can not be indicated by means of the TDR method. The low voltage impulse sent out by the Time Domain Reflectometer is not reflected at the faulty position, as the fault impedance compared to the insulation impedance of the healthy part of the cable is not significantly lower.

       

Electrochemical capacitor performance

The performance characteristics of electrochemical capacitors differ somewhat from those of onventional capacitors. In Fig. 4 the impedance plane representation (Nyquist plot) of an ideal capacitor and a simplified electrochemical capacitor, both having the same ESR (equivalent series resistance at 1 kHz), are compared.

Polymers ,Electrolyte and Organic

 Polymers

Polymeric materials, such as p- and n-dopable poly(3-arylthiopene), p-doped poly(pyrrole), poly(3-methylthiophene), or poly(1,5-diaminoanthraquinone) have been suggested by several authors [17–19] aselectrodes for electrochemical capacitors.

Transients in Capacitive Networks the Discharging

We know investigation how to discharge a capacitor while exerting some control on how the discharge time will be. You can of course place a lead directly across a capacitor to discharge it very quickly and possibly cause a visible spark.

Type of Capacitor and Leakage Current

Types of Capacitors

Capacitors like resistors can be listed under two general headings fixed and variable. The symbol for the fixed capacitor appears in , Note that the curve side is normally connected to ground or to the point of lower dc potential. The symbol for variable capacitors appears.