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International Journal of Pure and Applied Mathematics Volume 118 No. 9 2018, 755-764 ISSN: 1311-8080 (printed version); ISSN: 1314-3395 (on-line version) url: http://www.ijpam.eu Special Issue ijpam.eu

A Comprehensive Study of RF Antennas

Pawan Kumar1, Lavish Kansal2, *Gurjot Singh Gaba3, Mohammed Baz4 1,2,3School of Electronics & Electrical Engineering, Lovely Professional University, Punjab, India - 144411 4Computer Engineering Department, College of Computer and Information Technology, Taif University, Saudi Arabia – 26571 [email protected], [email protected], [email protected] *Corresponding Author – [email protected]

Abstract—In this era the advent of frequency operated This part depicts the principle reconfiguration systems micro electromechanical systems is an empowering innovation utilized by RF MEMS reception apparatuses [2]. These for another era of astute receiving wires prepared to do systems are partitioned in outer arrangements, which utilize powerfully self-adjusting their properties and giving an enhanced tunable receiving wire bolsters, and interior methodologies, execution. These section examinations the distinctive which associate straightforwardly with the reception apparatus reconfiguration systems, covering outside methodologies in view of tunable nourishing systems, and interior methodologies which radiation instrument. change the radio wire radiation component. The part likewise depicts the primary utilizations of radio frequency operated II. RF COMMUNICATION SYSTEM micro electromechanical systems receiving wires, mechanical Detailed block diagram of RF communication system is points of view, outline contemplations and future patterns. depicted in Fig. 1.Source Keywords—RF communication model; Monopole ; ; ; . Source is defined as a block that shares the data among the various subsystems. It generates the message data that is I. INTRODUCTION considered for analyzing the systems performance at the other part of the communication model. Nowadays the wireless technologies are continually advancing by giving high rate of information, lower costs, low A. Input transducer control utilization, compact gadgets. Reception apparatuses, as The input transducer converts the signal data which is radio- handsets, assume a basic part in this present in the physical form to the electrical form. It passes the advancement. Radio recurrence miniaturized scale electrical signal to the source encoding. electromechanical system (RF MEMS) is an empowering innovation for another era of insightful reception apparatuses B. Source encoder with the ability of powerfully self-adjusting their properties so Encoder is the circuit that converts the message bits from one as to keep up execution under operational or natural varieties. form to other form. In source encoding, sampling of the source RF MEMS is a magnificent innovation for the configuration of of information and quantization is done. Later on the source is receiving wire due to two fundamental properties. These are represented by the binary symbols or M-ary symbols. At receiver decoding of these received signals is done and they  Unrivaled execution of RF MEMS switches and variable are filtered back to the analog signals. capacitors contrasted with their relating semiconductor gadgets. C. Channel Encoding The maximum transmission rate is set by the famous  Remarkable coordination ability, empowering receiving Shannon capacity theorem. In this theorem the transmission wires with better execution and lower cost. reliability is quite high. In the presence of additive white Gaussian noise channel the representation is

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C = B*log2(1+S/N) BER level) of the coded framework with the non coded framework Where C = channel capacity D. Modulator S = signal power N = Noise power In modulator the input is baseband signal and by passing that baseband signal through this block that baseband signal is In order to reach up to the limit of Shannon theorem is to use modulated so that it can travel to the longer distances. the codes for the error control because it enables us to transmit Modulation is defined as the process in which certain the messages reliably from one place to other. The channel properties of the waveform which is assumed to be periodic codes are classified into two main types. These are the and also known as carrier signal changes with respect to the convolutional and block codes. Another reason for using other waveform which is called the modulating signal. channel coding is the coding gain. Coding gain is defined as the difference of the signal to noise ratio (SNR) (at a certain

Fig.1. Block diagram of RF communication system

E. Channel H. Decoder The transmitted signal is now passed through the channel This block is used to convert encoded bits format to the which works as an intermediate between the transmitter and analog form. But here the signals will be still electrical the receiver. The channel may have a natural noise as well as signals. These signal are further transmitted to the Destination. the additive noise. The natural noise includes noise generated I. Output transducer due to the environmental factors like the rain and humidity. The additive noise may be the additive white Gaussian noise This block is used to convert the signal in the form of that is used in order to cancel the other noise. electrical to the physical form. The output we get can be in any physical quantity form. F. Demodulator J. Destination Demodulator is used to separate the carrier signal from the modulating signal that was added earlier in order to send the Destination is the location where we want to transmit the signal to the long ranges. It converts the signal to two different signal in the end. When the signal reaches the destination then signals i.e. modulating signal and carrier signal so that it can the whole process of RF transmission is over. The destination be analyzed at the destination point. can use the received signal for the analysis of the the message data like we can calculate the bit error rate as well the signal to G. Channel decoder noise ratio of the signal by comparing the received signal data Channel decoder is used to remove the redundant bits that with the signal data that was transmitted after the modulation were added earlier in order to increase the accuracy of the bits process. This help the system in improving its performance by or to check whether the bits we are transmitting are we getting removing the factors that reduce the information content of the them at the receiver. data. This can be done by applying the various techniques for error detection and error correction.

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III. TYPES OF RF ANTENNAS  Log-Periodic Dipole Array

A. Log-Periodic Antennas

Feed point

Fig. 4. Representation of Log-Periodic Dipole Array

Fig. 2. Log Periodic Antennas Log-periodic dipole array which includes various dipole An antenna which takes a shot at an extensive variety of components is the most well-known antenna that is utilized in frequencies is log periodic antenna and is a multi-component, wireless communication technology as depicted in Fig. 4. directional thin beam reception apparatus as shown in Fig. 2. From the back end to the front end the size of these dipole- With the help of succession of dipoles the log periodic antenna cluster radio wires decrease. These radio frequency receiving is composed that are set with the receiving wire pivot after wires main light beam is produced by the smaller size front certain interims of space in time that are superseded by end. The component at the back end of the cluster is huge in frequency function which is assumed to be logarithmic in size whose ½ of the wavelength is operating at low range of nature. Log periodic array is the other name referred to this frequency. Towards the front end of the array the distance type of antenna. This antenna provides a variable bandwidth between the element is decreased wherein the arrays which are together with the directivity and antenna gain. small in size are placed. Amid the working of this, as there is variation in the frequency, a smooth move happens along the  Bowtie Antennas variety of the components, which prompts shape a dynamic area. B. Wire Antennas

L + D -

Fig. 3. Bowtie Antennas

A bowtie reception apparatus is otherwise called Biconical radio wire or Butterfly receiving wire as shown in Fig. 3. Biconical radio wire is a wide band reception apparatus which is omnidirectional in nature. It has low response in terms of Fig. 5. Wire Antenna frequency which is considered as a measure for this receiving Wire antenna is the very basic type of antenna. These are wire, and goes about as a high-pass filter. If the frequency used in a large number of applications because of their goes as far as possible, far from the frequency of the outline, construction. Wire antennas are also referred by the name of the radiation shape of the reception apparatus gets twisted and curved and linear antennas as depicted in Fig. 5. These spreads. The greater part of the bow tie radio wires are reception apparatuses are additionally subdivided into four as subsidiaries of biconical reception apparatuses. clarified beneath.

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 Dipole Antenna The short dipole receiving wire is rarely palatable from a productivity perspective on the grounds that a large portion of

the power entering this reception apparatus is dispersed as A Antenna Sections warmth and losses in the form of resistance likewise turn out to be continuously high.

Radiating element Radiating element

2L L

V V Fig. 6. Dipole Antennas

The most straightforward antennas includes dipole antenna Ideal Electric Conductor as one of its type. When there is a sinusoidal voltage difference between the two thin metal rods it constitutes the dipole antenna as shown in Fig. 6. For the length of rods the Fig. 8. Monopole Antennas choice is done in a manner that at the frequency of operation the wavelength must be of quarter length.Dipole Antennas are A monopole receiving wire is half of a dipole antenna used as a part of planning their own radio wires or different situated over a plane which is shown grounded as appeared in reception apparatuses. They are exceptionally easy to build the Fig. 8. In comparison to the half dipole antenna the and utilize. The dipole radio wire comprises of two metallic above the grounded plane will be similar. bars through which current and stream of frequency flows. However the power radiated totally is half as compared to that This current and voltage stream makes an electromagnetic of dipole and in the upper hemisphere portion of the dipole the wave and the get transmitted. field gets radiated. In comparison with the dipole antennas the directivity of these are double in number. Since this type of  Short-Dipole Antenna: antennas is providing the for the antennas mounted above the earth they can be used as vehicle mounted antennas.

Loop reception apparatuses have comparative attributes with

Radiating element both dipole and monopole radio wires since they are basic and Radiating element simple to develop. Elliptical, circular, rectangular and so on Feeder are the shapes in which loop antennas are accessible as shown in Fig. 9. Loop antennas fundamental characteristics are not Length dependent on its shape. These can be broadly utilized as a part of connections in the communication with around 3 GHz frequency. These radio wires can likewise be utilized as Fig. 7. Short Dipole Antennas electromagnetic field tests in the band of . From the wide range of radio wires the short dipole antennas are least difficult. Short dipole antennas are those radio antennas which are open circuited and here the term short is used for the signification of the wavelength as shown in Fig. 7. It does not offers importance to the frequency of operation but offers for the size of the antenna. This reception apparatus is made up of two end to end co-direct conductors and also having a small hole in between the conductors with the help of feeder. For a Dipole to be considered as short, the length of the emanating component should not be as much as a tenth of the wavelength.

Fig. 9. Loop Antennas

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As similar to the dipole and monopole antennas the impedance. Normal mode and the axial mode are the two efficiency of the antenna is determined by the outer line of predominate modes of the . Helical antennas loop antenna. Loop antennas are additionally characterized axial mode is used in a variety of applications. The dimensions into two sorts: electrically little and electrically extensive in of the helix are quite small in comparison with the wavelength light of the periphery of the loop. Electrically little circles of a in the normal mode. The helical antenna can act as short solitary turn have little radiation resistance contrasted with dipole antenna or the monopole antenna. The dimensions of their resistance of the loss. The radiation resistance of little the helix are same when compared with the wavelength in the loop receiving wires can be enhanced by including more turns. axial mode. Multi-turn loops have better radiation resistance regardless of the possibility that they have less productivity.  Yagi-Uda Antenna

Because of this, the little loop radio wire are for the most part utilized as reception antennas where loss is not compulsory. Little loop antennas are not utilized as transmitting radio wires because of their low effectiveness in terms of efficiency.The loop antennas which are assumed to be resonant are moderately extensive, and with the help of the operation of wavelength these are directed.Since they are used at larger frequencies like UHF and VHF wherein their size is convenient, they are called large loop antennas. Loop antenna is distorted into various shapes like square, spherical, and so forth, and have comparable qualities, for example, high- radiation proficiency and can be analyzed as folded dipole antenna. Fig. 11. Yagi-Uda Antenna

C. Travelling Wave Antennas Another reception apparatus is the Yagi-Uda receiving wire which uses the passive components in it as shown in Fig. 11.

This kind of receiving wire is cheap. Yagi-Uda antenna can be  Helical Antennas built by using one reflector and one executive or directorial component at minimum. Yagi radio wires is constructed by using a wire at the receiver end which can have one reflector, dynamic component of dipole which is driven folded, and directorial components, mounted for flat or horizontal in the forward course.

D. Antennas

Microwave receiving wires are those reception apparatuses which operates under the microwave frequency range. Microwave antennas are used for a large number of applications.

 Rectangular Micro strip Antennas

Fig. 10. Helical Antennas

Helical antennas acts as directional receiving wire as depicted in Fig. 10.The other name given to this type of antenna is helix antenna. The construction of these antennas includes very simple structures that may consist of one, two or more than that wires in which each one of them are wounded to form a helix which is generally backed by the ground plane or the shaped reflector and is driven by the choice of suitable feed. The properties of radiation in helical antenna is related with the condition that the structure‟s electrical size, wherein the pitch and wire size are less sensitive to the input Fig. 12. Rectangular Micro strip Antennas

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 Parabolic Reflector Antenna For shuttle or air ship applications – in light of the particulars, for example, estimate, weight, cost, execution, simplicity of establishment, and so forth – low profile radio wires are favored as depicted in Fig. 12. These reception apparatuses are known as rectangular microstrip receiving wires. It is also named as . For the which is typically set behind the ground plane they just require space. The real hindrance of utilizing these receiving wires is their narrow bandwidth and inefficiency, which is regularly a small amount of a percent or, and no more, a couple percent. Fig. 14. Parabolic Reflector Antenna

 Planar Inverted-F Antennas Parabolic reflector antenna emanating surface has vast dimensionality in comparison with its wavelength as depicted The constituents of Linear inverted F antenna (IFA) includes in Fig. 14. For the determination of certain features of planar inverted F antenna in it. In this type of antenna the wire antennas geometrical is used that depend upon rays and radiating element is put back by the plate that is used to wave fronts. The One of the valuable properties of this increase the bandwidth. The upside of these reception receiving wire is the transformation of a diverging apparatuses is that they can be covered up into the body of the sphericalwave front into parallel wave front that delivers a cell phone when contrasted with various sorts of radio wires tight light emission of reception apparatus or antenna. Horn like a whip, helical receiving wires, and so on. The other feeds, Cartesian feeds and dipole feeds are the different sorts preferred standpoint is that they can diminish the regressive of the feeds that use the parabolic reflector. radiation towards the highest point of the receiving wire by retaining power, which upgrades the efficiency. They gives IV. LITERATURE REVIEW high value of gain in both flat and vertical states. This element In the current scenario it is required that the systems we are is most vital for any sort of radio wires utilized as a part of using in term of communication must have high speed and wireless communications. along with that they must have quick mobility. WiMAX is E. Reflector Antennas generally based on the orthogonal frequency division multiplexing (OFDMA) [1]. OFDMA is providing us the fast speed and mobility in the frequency selective environment.  Antenna There are a lot of beam forming algorithms proposed. The

most of the research is focused on the traditional single carrier

beam forming algorithm.Due to this the complexity of the

system increases and along with that the high computational load is resulted. The performance of the conventional single

antenna BS with the m-WiMAX SA BS is compared [1].The

single carrier with frequency domain equalization (SC-FD)and

high performance OFDM is compared [2]. The frequency

domain equalization (SC-FD) has got an importance in the recent years in the field of broadband wireless communications. OFDM is used during transmission in order

to divide the present bandwidth into parts of N subcarriers. In

a case where the number of carriers are more enough then the

bandwidth per subcarrier is narrow with respect to the

Fig. 13. bandwidth which is assumed to be coherent. When OFDM is compared with the SC-FD it is analyzed that both uses the Corner reflector antenna is the reception apparatus that same construction block but in case of the SC-FD the IFFT is includes at minimum one dipole component that should be moved from the transmitter side to the receiver side. This placed before the reflector of the corner as shown in Fig.13. results into the effect that SC-FD symbol information get By using the reflectors the directivity of any antenna can be spread in the entire band of frequency. The meaning of this is expanded. For the proper direction of radiation in the forward that the downfalls in the channel do not vanishes the entire course a conducting sheet is utilized behind the wire antenna. symbols.

The reason behind this is that the each symbol information can be retrieved from the subcarriers. The MIMO systems betters the rate of information and along with this it makes the communication more reliable.The improvement of channel

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capacity in terms of the MIMO systems can be done [3]. This effect is increased by giving two additional flanges with the is achieved by mixing the usage of transmission power half wave long patch edges and then molding them in the allotment via the water pouring algorithm in several antenna downward direction to form the reverse U-shaped patch. There configurations and antenna selection techniques (AST). The is a minimum dimension antenna which is called active MIMO systems is having a shortcoming that it requires extra integrated antennas which is the quasi-optical power combiner RF modules. While minimizing the cost connected with the structure [8]. multiple RF antennas one can use antenna selection techniques in which „p‟ antennas are selected at the transmitter side as IMPATT diodes and schottky diodes are the only two poles well as at the receiver side. The condition for the transmitter is element which are possible for the frequency bands near about p <= mt and for the receiver is p <=mr. The channel capacity 61Ghz and 76.5Ghz assigned for the application of industry equation is dependent on the selection of the P antennas in an and vehicles. IMPATT diode negative resistance is only algorithm which is iterative. This algorithm calculates all the several ohms which requires a small impedance termination to combinations of the antenna in order to get the channel obtain oscillations. This is regarded as the major drawback of capacity which is needed to be highest.The micro strip IMPATT diode design. The cut off frequency of magnetically antennas can be optimized by the artificial neural networks biased micro strip patch antenna can be optimized by the GA (ANN) [4].The algorithm that is used for the optimization of tool [9]. In GA tool the population which reproduces the best artificial neural network is the back propagation algorithm fitness function are called parents. After that the genetic which is the type of multilayer perceptron network. This is algorithm enters into the phase of production in which parents more effectual for the mapping problems which are are selected by the selection process. Crossover is the GA nonlinear.The leaf shaped micro strip patch antennas are also operator with the help of which the parents reproduce the proposed which includes various shapes triangular with basal population under which the random points are selected. This lobes, resembles a band, with finger like lobes, blunty tipped, process is stopped when the new generation is complete. The with a spine like tip, pointed at both ends, palmate (divided GA works in five phases – random number generation, a lateral lobes), pointed (barbed base).While implementing fitness evaluation, and genetic operations for reproduction, infrared imaging it is required that there must be a proper crossover and mutual operations. The large area lubricant cooling. There is one such device that overcome this removal by using the capacitively coupled RF and disadvantage is the antennas coupled metal insulator metal microwave plasma source can be done [10]. The plasma (MIM) detector which is also known as rectenna. cleaning is done by using RF plasma processing unit PPU- 400, cleaning reactor with plasma source SLAN II.For the The utilization of the MIM diodes can be done up to a high linear dipole replacement when the broadside radiation and frequency i.e 150 THz. A reliable device than this is the thin low profile is required, the cylindrical slot and folded slot film MIM diode which overcome its poor reproducibility and antennas are used [11]. For the well-defined pattern nulls instability problem [5]. Thin film MIM diodes are fabricated normal to the axis of CCPW these antennas shows quite broad using a variety of combination like Al-Al2O3-Al, Cr-CrO-Au, beam widths.With the change in the resonant frequency of Al-Al2O3-Ag, Nb-NbOx-Au, Ni-NiO-Au, Ag, Ni, Pt. The patch antenna (5.2 Ghz to 1.8 Ghz) high degree of scattering pattern and the radiation pattern of the microstrip miniaturization is resulted which is about 89 % [12]. slot antenna is analyzed [5].The radio frequency identification technology along with the frequencies of the use of this With such a high compactness the value of gain is 1.77dbi technology are discussed [6]. RFID tag play a vital role in this that can be used for the day to day antennaapplication and it technology. It is composed of two components- antenna and also justifies the high performance of antenna. The RF MEMS integrated circuit. The building block of the integrated circuit switches which are used are not stressed up to their tensile are the memory, antenna and a microprocessor. The RFID are strength. Along with the analysis of stress the force that is differentiated by two kinds of tags. First one is the read only required to pull the membrane in the downward direction is tag and second one is the read/write tag. The read only tags in also taken care of. Dielectric charging is the major limitation general do not have the storage capacity of data. It has only of the RF MEMS. For the coated wire monopole antenna pointing to the database unique ID which is prewritten. The calculations substantiate that dielectric material has resonator RFID which different RFID tags are detected up to different action in it. But for the slot antennas and coated Yagi antenna ranges depending upon their frequency of usage. Every no physical interpretation is that far constituted [13]. The country has its own frequency band for the operation of the antennas which are flexible, reversible and stretchable has RFID systems [6]. The inverse U-shaped patch and a W- most recently showed the results which are quite promising in shaped ground of broadband probe fed patch antenna has been the category of tunable RF devices and in that case by proposed [7]. By bending the traditional ground plane into changing the structure dimensions frequency response can be inverted V-shape we can get the W-shaped ground. This can controlled. For the electronics applications which are wearable be seen in the direction of the patch antenna which is resonant. the capacity of this antennas can be used for the strain sensing Along with this appropriate flanges on the two straight edges applications [14]. With the usage of 430 MHz operating are added to the bent ground. For making the size of antenna frequency of microcontroller an RF power harvester can be more compact, at the radiating edges the capacitive fringing used [15]. Vector Network Analyzer measurements and

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establishment of a low power link in between the tag and the in the channel capacity. The I-AST is employed in order to base station are used for the evaluation of antenna give the better transmitting conditions and along with that in performance and operation of the power harvester. order to determine the channel state information. If we know the channel state then under the rule of assigning more power V. COMPARISON OF RF ANTENNAS we are able to allocate power in a better way and we are able Over the most recent couple of years, a few reception to implement the WPA. The channel capacity has been apparatus have been proposed that operate on radio frequency. significantly improved by the usage of the I-AST and WPA as Among different receiving wires, microstrip patch reception compared to the conventional systems which used to divide apparatuses are generally utilized in view of their position of the power equally among all the transmit antenna. The AST safety, light weight, and planar structure. Customary patch and WPA technique can also be implemented for a better receiving wires are rectangular in shape, however varieties in multiple input multiple output (MIMO) system. In MIMO if their fundamental plan are made for various purposes. This we use the AST technique it reduces the number of RF chains paper starts with a clarification and exchange of various plans, used as well as the cost and if we use the WPA then it set forward with a point of scaling down, consonant dismissal, allocates the power efficiently. Also in case of AIAs there are and reconfigurability. At long last, microstrip patch antenna many concepts that has been completely researched. The organized are assessed and contrasted and an additional functionalities like injection locking, homodyne accentuation on the different strategies received to acquire a mixing and IQ Doppler detection has been added. If a reduced rectenna, symphonious dismissal usefulness, and adequate design method is applied then an efficient and polarization and frequency selectivity. reliable operation of AIAs either it is two pole active device or three pole active device can be obtained. A. Rectenna A rectenna is a specific sort of receiving wire that redresses REFERENCES approaching electromagnetic waves into DC current, depicted in Fig. 15. In the course of the most recent century, the [1]S. Hyeon, C. Lee, C. Shin and S. Choi, “Implementation of a Smart Antenna Base Station for Mobile WiMAX Based on OFDMA”, EURASIP improvement of rectennas for remote power transmission has Journal on Wireless Communications and Networking, Vol. 2009, pp. 1-9, made incredible progress in actualizing particular capacities March-2009, DOI:10.1155/2009/950674. and applications, for example, RFID labeling frameworks, sensor batteries or capacitors, WLANs, WiMAX, and [2] J. Tubbax, L. Perre, M. Engels, H. Man and M. 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