TYPES OF PROPAGATION FOR TRANSMISSION OF DATA IN UNGUIDED MEDIUM

TYPES OF PROPAGATION FOR TRANSMISSION OF DATA IN UNGUIDED MEDIUM

1. Types of Propagation Presented by: Dr. Upama Das Sharad Institute of Technology College of Engineering, Yadrav

2. INTRODUCTION Wave propagation in a transmission line refers to the movement of an electromagnetic wave along the line. When a voltage is applied to the input of the transmission line, an electromagnetic wave is generated that travels along the line, carrying energy and information. Figure 1: Wave Propagation

3. PROPAGATION Ground Propagation: In the ground propagation , the electromagnetic wave is propagated close to the atmosphere i.e. between ionosphere and earth surface . These electromagnetic waves are the low-frequency waves transmitted in all direction and The wave follows the curvature of the earth . More the power of the signal longer the distance it travels. The unguided media propagates electromagnetic wave from source to destination in three methods. Figure 2: Ground Propagation

4. Advantages of Ground Wave Propagation The factor of large wavelength supports efficient bending thereby causing  less attenuation . The signal loss due to atmospheric conditions is less. Disadvantages of Ground Wave Propagation The  distance  between the transmitting and receiving end must not be very large. The operational frequency range is limited to up to 2MHz . Applications Television signal broadcasting, target detection for military purposes, radio signal transmission, and in all such applications those require a distance of operation in the local range.

5. ii) Sky wave Propagation: In sky propagation, the electromagnetic wave with a higher frequency is radiated up in the ionosphere from the source transmitter antenna which gets reflected back to the earth surface . In sky propagation , the electromagnetic wave travel a longer distance and it can be received thousands of Kilometres away from the transmitter . Figure 3: Sky wave Propagation

6. Advantages of sky wave propagation The   frequency range  of operation is considerably  high . Attenuation due to atmospheric conditions is less . It supports  large distance propagation. Disadvantages of sky wave propagation Long-distance propagation requires  large-sized antennas . Due to the presence of the ionosphere, near and far during night and day respectively there exist variation in signal transmission in day and night. Applications Sky wave propagation is widely used in mobile and satellite communications as it needs suitable atmospheric conditions.

7. Features of Line of Sight Propagation Space wave propagation is commonly used for short-range radio communication . Space wave propagation is also used for satellite communication. The maximum range is approximately 40kilometres for radio waves at 100 MHz. Space wave propagation is used in a wide variety of applications, including television broadcasting, mobile phones, wireless LANs, and remote sensing.

8. iii) Line of Sight Propagation: In the line of sight propagation the electromagnetic wave with very high frequency is ‬‎ transmitted in the “straight-line” direction from the transmitter antenna to the receiver antenna. In this way, the electromagnetic wave does not get affected by the curvature of the earth because the transmitter and receiver antenna are either tall or close enough to maintain the line of sight. Figure 4: Line of Sight Propagation

9. Propagation Modes

10. REFERENCES https://testbook.com/key-differences/difference-between-guided-and-unguided-media https://electronicsdesk.com/ground-wave-propagation.html https://binaryterms.com/unguided-transmission-media.html https://testbook.com/key-differences/difference-between-guided-and-unguided-media https://www.includehelp.com/computer-networks/unguided-transmission-media.aspx https://www.geeksforgeeks.org/types-transmission-media / https://resources.system-analysis.cadence.com/blog/msa2021-wave-propagation-in-lossy-dielectrics