Thursday, December 5, 2019
Strength and Weakness of the Antenna-Free-Samples for Student
Questions: 1.Different antenna, such as yagi, horn, and celluar antennas, etc. has different merits. Research these technologies in details and pay specific attention to how they are used as well their strengths and weakness. 2.Compare and contrast the multiplexing techniques CDMA and FDMA in the area of wireless networking? Answers: 1.Different types of Antennas are: Horn Antennas A horn antenna is also called microwave horn antenna. It is used in many applications for microwaves where level of reasonable directives is needed. There are different types of horn antennas available including conical horn, pyramid horn antenna and the corrugated horn antenna. The antenna is used in the reception and transmission of RF microwave signal and it is usually used in conjunction with waveguide feeds (Mizoguchi et al ., 2016). A horn antenna is a form of antenna that consist mainly flared waveguide which is in the shape of a horn. It has that effect that enables a transition between the free space and the wave guide and it also directs wave in a beam. Strengths The following are the strength of the antenna. Impedance matching is good. Greater directivity. Standing waves are avoided. Small minor lobes are formed Narrow beam width (Ekti et al., 2016) Weakness The following are the weakness of the antenna. Flare angle and length of the flare should not be very small Designing of the flare angle, decides the directivity. Yagi Uda Antenna The yagi uda antenna is the most commonly used antenna for TV reception over the last few decades. This type of antenna is the easiest to use and popular antenna with a good performance. This type of antenna is famous for its directivity and high gain. The frequency range in which the antenna works is around 30 MHz to 3GHz which belong to the UHF and VHF bands ok frequency. Strengths The following are the strength of the antenna. High directives is achieved Easy of handling and maintenance Less amount of power is needed. Broader coverage of frequency High gain is achieved. Weakness The following are the weakness of the antenna. This type of antenna is prone to atmospheric effects.This type of antenna is prone to noise. Helical Antenna Helical antenna is an example of wire antenna as it forms the shape of a helix. The operation frequency of the helical antenna is around 30 MHz to 3 GHz. This antenna works in the UHF and VHF ranges. It is one of the simplest antennas which provide polarized waves circularly (Wong et al.,2017). This type of antenna is usually used in extra terrestrial communication which involves satellite relays etc Strengths The following are the strength of the antenna. Simple design Wider bandwidth Highest directivity Can be used at HF and VHF bands also. Circular polarization can be achieved (Skinner, 2016). Weakness The following are the weakness of the antenna. The antenna size is large so it requires more space. Efficiency decreases with the number of turns. Future prospective The helical antenna would be a dominant player in the near future because of its mode of operation. There are two modes of operation Normal or perpendicular mode of radiation In this mode of radiation, the radiation field of the helix is normal. The radiated waves are polarized circularly. This is obtained if the dimension of the helix is small when compared to wavelength. Axial or beam mode of operation In this mode of radiation, the field of radiation is in the end- fire direction along the helical axis and the wave is circular or circularly polarized. The radiation is broad and the directional along the beam axis producing minor lobes at oblique angles (Skinner, 2016). 2.Compare and contrast the multiplexing techniques CDMA and FDMA Code Division Multiple Access (CDMA) is a method access normally used for 3G radio communication and some other technology. The technicality of CDMA technology has given significant advantages over other parallel technologies which are in term of spectrum efficiency and overall performance (Rogers, Richard Noortje, 2016). Frequency Division Multiple Access (FDMA) is one of the most common analog multiple access methods .the bandwidth is divided into channel of equal bandwidth as a result of which each conversation is carried on a different frequency In code division multiple accesses each user is assigned a different pseudorandom binary sequence that modulates the carrier, with respect to the waveform it is spreading across the spectrum and gives each user a unique code pattern. With frequency division multiple access different signals are assigned to the frequency channel. A frequency is a channel. Frequency is mainly a basic technology in the analog advanced mobile phone system (AMPS) (Rogers, Richard Noortje, 2016). In FDMA each channel can be assigned to only one user at each time. FDMA can also be used in Total access Communication system. The broad difference between CDMA and FDMA are as follows: CDMA (code division multiple access) Every narrow signal is multiplied by wideband spreading signal usually known as codeword. Only the desired codeword is detected by the receiver rest appear as a noise. Every user has a different pseudo-code which is orthogonal to others Same frequency is used by every user and simultaneous transmission occurs It is mandatory for the receiver to know about the transmitters codeword FDMA (Frequency Division multiple access) Bandwidth of channel is relatively narrow which is known as narrow band system Tight filtering is needed in order to minimize interference Little or no equalization for spreading symbol is needed. Bandwidth of the channel is not in use. Analog links are suitable for FDMA (Etzkowitz, 2016). References Mizoguchi, F., Yamauchi, T., Ishihara, Y., Ishikawa, K. (2016). U.S. Patent Application No. 15/387,044. Ekti, A. R., Shakir, M. Z., Serpedin, E., Qaraqe, K. A., Imran, M. A. (2016). On the Traffic Offloading in Wi-Fi Supported Heterogeneous Wireless Networks. Journal of Signal Processing Systems, 83(2), 225-240. Wong, V. W., Schober, R., Ng, D. W. K., Wang, L. C. (2017). 1 Overview of New Technologies for 5G Systems. Key Technologies for 5G Wireless Systems, 1. Skinner, B. F. (2016). The technology of teaching. BF Skinner Foundation. Etzkowitz, H. (2016). The evolution of technology transfer. Rogers, Richard, and Noortje Marres. "Landscaping climate change: A mapping technique for understanding science and technology debates on the World Wide Web." Public Understanding of Science (2016).
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