Waveguides

Today we shall concentrate on one of the Transmission media called wave guides. A hollow conducting tube to transmit electromagnetic waves is termed as wave guide. A waveguide is a hollow tube designed to carry microwave energy from one place to another place. Waveguides may be used to carry energy between pieces of equipment or over longer distances. Waveguides are made from copper, aluminum or brass. These metals are extruded into long rectangular or circular pipe

The electric and magnetic fields of electromagnetic wave are confined to the space within the guide and made to propagate down the length of the wave guide.

Characters of waveguides:

• The propagation takes place through the dielectric field.
• Propagation is in terms of electric and magnetic fields rather than voltage and currents.
• The electric and magnetic fields that exist inside the waveguide are solution of Maxwell’s wave equation.
• Each waveguide has cut off frequency that decides the dominant mode of propagation.

Coming to the types of waveguides. There are three types of waveguides namely:

1. Rectangular waveguide:

     2.circular (cylindrical) waveguide:

     3.Ridged waveguide:

Advantages of waveguides:

• The waveguides can be used at much higher frequencies than the co-axial cables.
• Easy to manufacture than co-axial cable because waveguides are hollow.
• Waveguides do not have either inner conductor or dielectric material, therefore power handling ability is improved. It is about 10 times as high as for co-axial air dielectric rigid cables.
• Power losses are less.
• There is no radiation loss.

Applications:

• They are at their supreme in microwave transmission.
• Used to connect Radar transmitter to antenna.
• Used to channel the received echo to the receiver from the antenna

INTEGRATED CIRCUIT

Hi friendz today we shall have some knowledge about integrated circuits (abbreviated as IC).Before knowing the definition of ICs we shall know why an IC was developed?

 Now a days integrated circuits are more popular. In the early days some discrete components like capacitor, resistor, diodes, were used to be connected in a definite pattern(using wires) called electronic circuit. As the technology advanced the discrete components were integrated on a single chip this is called integrated circuit.

Integrated Circuit

Now coming to the definition : An IC is one in which a number of circuit elements like resistors, capacitors, transistors, diodes etc are fabricated on a small semi conductor chip to perform a complete function.

Classification of Ics:

1. Classification by Scale of integration:

·        SSI (Small scale integration) : ICs having 0 to 12 components on a single chip. Ex: Logic gates, Flip-flops.

·        MSI (Medium Scale Integration): Ics in this category contains 13 to 99 electronic components on a single chip. Ex: Adders, registers, encoders, multiplexers.

·        LSI (Large scale integration): Ics having 100 to 9999 components in a single chip comes under this category. Ex:Microcontroller, RAMs, ROMs

·        VLSI (Very Large scale Integration): Ics in this have 10000 to 99999 components in a single chip. Ex: Advanced microprocessor, Memory chips.

·        ULSI (Ultra Large Scale Integration): The components in the Ics of this type are more than 100000. Ex: Single chip Microprocessors, memory chips.

    

2. Classification by Structure:
• Monolithic
• Film Passive : Thick film and Thin film ics
• Hybrid Ics

3. Classification of Ics by function:

•           Analog Ics

Analog IC

• Digital Ics

Digital IC

Advantages of Integrated Circuits:

• Smaller weight.
• Low cost
• Highly reliable
• Low power consumption
• Easy replacement

Disadvantages of Integrated circuits:

·        Transformers, inductors can’t e fabricated.

• Large values of capacitance > 30pF can’t be built.
• The components in the IC can’t be repaired instead whole IC should be replaced.
• Not possible to modify circuit parameter

 Hope this was useful .. Keep visiting for exciting posts!!! 

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