Periodic Bandgap Structures

PBG structures are periodic in nature, which may be realized by drilling, cutting and etching on the metal or substrates. They may be formed in the ground plane or over the substrate. 

 

Periodic structures

Due to the realization of growing demand for larger bandwidth, high capacity RF and microwave devices as well as better efficiency in the field of wireless technologies new technologies of designing such devices are being reported all over the world. 

 Figure 3.16: 1D circular pattered EBGS etched beneath the T-line designed by Zeland ie3d software.

On the consequence of such latest technologies realizing microwave filters and antennas with Planar Electromagnetic Bandgap Structures are one of the best of them.

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.

Three Phase Generator

The three phase generator in has three induction coils placed 120 degree apart on the station , as shown symbolically. Since the three coils have an equal number of turns, and each coil rotates with the same angular velocity the voltage induced across each coil has the same peak a value shape and frequency.

Current

The question 'Which came first the chicken or the egg?' can be applied here also because the layperson has a tendency to use the terms current and voltage interchangeably as if both were source of energy it is time to set things straight,

Voltage

If we separate the 29th electron from the rest of the atomic structure of copper by dashed line as shown we create regions that have a net positive charge as shown in and for the region inside the dashed boundary , the number of points in the nucleus exceeds the number of orbiting electrons by i so the net charge is positive as shown in both figures.

Solid State Era

In 1947 physicists William Shockley, John Bardeen and Walter H. Brattain of Bell Telephone Laboratories demonstrated the point contract transistor an amplifier constructed entirely of solid state materials with no requirement for a vacuum glass envelope or heater voltage for the filament.

Sinusoidal Ac Voltage Characteristic and Definitions

Sinusoidal ac voltage are available from a variety of sources. The most common source is the typical home outlet, which provides an ac voltage that originates at a power plant. Most power plants are fueled by water power ,oil, gas or nuclear fusion.

Nodal Analysis

A close examination of appearing reveals that the subscript voltage at the node in which kirchhoff's current law is applied is multiplied by the sum of the conductance attached to that node. Note also that the other nodal voltages within the same equation are multiplied by the negative of the conductance between the two nodes.

Constant Current Alarm System

The basic component of an alarm system using a constant current supply are provided . This design is improved over that provided in this lesson in the sense that it is less sensitive to charges in resistance in the circuit due to heating humidity charges in the length of the line to the sensor and so on.

Conductors & Insulatoes

Different wires and place across the same two battery terminals allow different amount of charge to flow between the terminals. Many factors such as the density, mobility and stability characteristics of a material account for these variation in charge flow.

Distribution network configurations

Distribution networks are typically of two types, radial and interconnected (see spot network). A radial network leaves the station and passes through the network area with no normal connection to any other supply. This is typical of long rural lines with isolated load areas.

Designing equation

In the PBG engineering it is a conventional rule to use Bragg’s condition [13] to calculate the central stopband frequency provided by PBGSs.

Literature Survey on PBG Assisted Microwave Devices

A comprehensive literature survey on recent development of PBG structures and their applications to microwave devices including antennas has been reported in this chapter. PBG structures are found to play vital roles in enhancing the performance of the microwave components and devices.

Plannar Photonic Bandgap Structures

Planar PBGSs are a classes of periodic, which are photogenic analogs of the semiconductors. Electromagnetic (EM) waves behave in photonic substrates as electrons behave in semiconductors. Due to these characteristic PBGSs are known as EM bandgap structures (EBGSs). PBGSs exhibit wide band-pass and band-rejection properties at microwave and millimeter-wave frequencies and have offered tremendous applications in active and passive devices [1]-[12].