Abstract – The purpose of this research presented in this study is to analyze the effects of wireless moving ridges propagating through flora and to develop a semi-empirical theoretical account of signal fading in the wood. This was achieved through a combination of theoretical surveies and deterministic modeling to turn out that the proposed theoretical account is sufficient for extension anticipation in wood. The chief attack in this analysis is the presentation of conjugate lossy transmittal line with nonlinear tonss for the survey of wireless extension in wood. An effort is done on the transmittal line analysis in order to analyze the losingss in the wood by an empirical attack. To develop the theoretical account, major losingss occurred in transmittal line are taken in history. By utilizing the prevailing feature of the lumped elements in the transmittal line, the loss factors are derived in order to suit into the loss equation of the forest theoretical account. The concluding theoretical account will consists of lumped elements tantamount circuit with the coveted parametric quantities. By utilizing this circuit, an analytical consequence is shown for the transmittal line parametric quantities that fixed into the forest theoretical account. Nevertheless, merely the consequence of fading characteristic regard to the extension invariable is taken into history. This consequence has become the deciding factors for the public presentation of the forest theoretical account owing to the high frequence transmittal through the leaf. An of import characteristic of this paper is to turn out that these analytical consequences may be presented in footings of transmittal line parametric quantities with less complicated computation while acquiring acceptable consequences for wireless losingss in a wood environment. It is alternatively represent a simple solution instead than the complicated computation.
In nowadays engineering, information can be transmitted in several ways. However, the usage of electromagnetic energy for this intent is so attractive because physical connexions are non needfully required. This brings up the radio engineering which normally used for wireless transmittal in early twentieth century. The connectionless characteristic of electromagnetic extension is utilized in many technology systems such as long distance point to indicate communications, radio detection and ranging, wireless and telecasting broadcast medium, navigational AIDSs and so on. The same considerations besides make electromagnetic energy utile in detectors systems in which the information is obtain from and to which the energy is directed. Electromagnetic detectors normally used for mensurating the negatron concentrations in the Earth ‘s upper atmosphere, the wave-state of the sea, the wet content of the lower ambiance, the wet in dirts and flora, the size distributions of atoms in fume and many other parametric quantities. Radio extension research largely focuses on the interaction between wireless moving ridges and the transmittal media. This is the scientific construct behind the functionality of wireless phones every bit good as countless other radio communications engineerings. Over the past two decennaries, the demand for and dependence on such radio merchandises, services and webs have grown quickly. As traffic burden in wireless webs increases, there is a demand to better the wireless spectrum which is used by these engineerings.
In the development of electromagnetic theory, we were understood that the innovation of radio signalling by wireless and the development of electromagnetic aerials is needed to convey and have the signals with high efficiency. The thought that electromagnetic signals might propagate over considerable distances with the speed of visible radiation was foremost proposed in 1865 by James Clerk Maxwell. He added the displacement current term to the set of equations regulating electromagnetic events, called Maxwell ‘s equations. He deduced that among their possible solutions rectilinear wave gesture would be included. Thus, an electromagnetic perturbation should be capable of being propagated over significant distances. Therefore, the really possibility of radio communications is founded on Maxwell ‘s research. Today, Maxwell ‘s equations form the footing of computational electromagnetisms. This anticipation was verified by experimentation by Heinrich Hertz in a series of experiments conducted in the late eightiess. Most of his experiments utilised high frequence currents to bring forth the first radio moving ridges, therefore formalizing the theory of Maxwell. He used the moving ridges of about one metre wavelength which besides termed as the ultra-high frequence ( UHF ) scope and transmittal distances were by and large on the order of a few pess in obtaining the coveted consequence.
PROPOSE FOREST MODEL DESCRIPTION
In a lossy transmittal line, the fading invariable can be broken into at least four constituents affecting the metal loss, dielectric loss due to loss tangent, due to conduction of the insulator and due to roll radiation [ 1 ] . The parametric quantities contribute to the losingss are resistance per unit length, conductance per unit length, induction per unit length every bit good as electrical capacity per unit length. Different loss mechanisms will hold different behaviours over conduction value and frequence scope [ 2 ] . These different behaviours are found utile in finding the forest fading loss under certain status. In this survey, a coaxal line type transmittal line will be used to develop the appropriate theoretical account for the wood. This is due to the round symmetricalness of the line which best used to stand for a line of trees in a wood. Besides, coaxal line besides less susceptible to complicated loss effects such as propinquity consequence and radiation loss which involved hard computation to detect the loss.
A transmittal line theoretical account is chosen to develop the forest theoretical account as its parametric quantity is comparable to the forest characteristic. For case, in a long lossy transmittal line, the frequence of the signal and the wavelength constituents are taken into history while deducing the transmittal line equation. Similar to the forest theoretical account, frequence constituent act as an of import parametric quantity in finding the fading happened in the wood.
To fit the feature of transmittal line with feature of wood, the loss factor of transmittal demand to specify first since forest act as obstruction which cause fading. Coaxial overseas telegram is optimum for transporting wireless moving ridges runing in frequence from 3Hz to 3000GHz. Coaxial overseas telegram is comprised of an interior music director of lesion Cu environment by a polythene insulator. On the top of insulating polythene bed, there is an outer music director of braided Cu and so followed by PVC jacket.
The interior music director of Cu wire and the outer Cu is really of import because it defined the features electric resistance, Zo from the electrical capacity and induction per unit length of the overseas telegram. In a lossy transmittal line, there are at least four constituents which affect the signal quality. The constituents are metal loss, dielectric loss, conduction of dielectric and isolated radiation. The cardinal electrical parametric quantities which contribute to losingss are shunt electrical capacity per unit length, series induction per unit length, series opposition per unit length and shunt conductance per unit length. The opposition per unit length is merely the opposition of interior music director and the shield at low frequences. Once the frequences get higher, skin consequence will increases the effectual opposition by restricting the conductivity to a thin bed of each music director. The shunt conductance is normally really little because dielectrics with good insulator belongingss are used. At high frequences, a insulator can hold a important resistive loss.
Figure 2.1: Coaxial Cable
In the proposed theoretical account, the transmittal line feature is matched to the forest feature with some little accommodation to deduce the loss factor. It is necessary to pattern the forest environment before develop the theoretical account to guarantee that forest feature can be matched to the transmittal line characteristic. Several considerations and premises on the forest denseness, antennas separation distance and the aerials tallness are taken into history in developing the forest theoretical account. In patterning the forest profile, the first premise made is the location of wood on a level terrain with about equal size of trees. The tree age, tallness and diameter of bole is besides the considerable parametric quantities where all of them are assumed to be equal and the forest consisting of the same types of trees. The denseness of the wood is measured based on the bole bed which mean that the canopy is holding the same denseness as the tree bole and it is taken as a whole unit alternatively of considered individually. Since the present survey will merely concentrated on the feature of the forest elements, hence, all others randomness such as the temperature of the forest, parasitic elements and traveling objects in the wood will be fixed.
From all the premise made above, a wood theoretical account is developed as shown in Figure 2.1. Besides, the trees separation is assumed to be really near to each other and its value is much smaller than the distance between the sender and receiving system. The interface between the canopy-trunk and canopy-air is assumed to be level. The forest theoretical account is built as shown below with both conveying and having antenna situated inside the flora. The trees act as obstructions in the wireless way doing both soaking up and spread of wireless signals.
Figure 2.2: Basic Forest theoretical account
Relationship of Forest Density and Attenuation Loss
Kent Chambelin [ 12 ] has proven that forest denseness contributes the major loss upon radio extension in wood. His research is followed up by Tamir [ 3 ] who denotes that a denser wood will see more loss due to the hapless conduction. This relationship is closely related to the transmittal line theoretical account which expressed the dominant loss due to fading in metal conduction. The fading loss is modeled by the opposition per unit length constituent in transmittal line theoretical account and chiefly cause by skin consequence. An of import parametric quantity in this derivation is the conduction of the stuff due to current flow.
A wood theoretical account built to analyze the relationship of forest denseness to the loss factor is shown in Figure 2.2. The trees are separated with a distance much smaller than the antenna separation. The transmission and receiving aerial are located with certain height inside the flora. However, since the present survey merely history for the denseness of the forest, the transmission and having aerials will be set into a fixed value in this analysis.
Harmonizing to theory of transmittal line, the opposition per unit length can be derived as:
The forest denseness contributes the major loss when wireless moving ridge base on ballss through the wood. This can be related to the opposition per unit length constituent in transmittal line theoretical account which cause fading due to clamber consequence. When the frequence is higher, skin consequence increases the effectual opposition by restricting the conductivity to a thin bed of each music director. In figure 4.1, a and B is the antennas tallness with trees separation, d much smaller than distance of conveying and having aerial. This aerial is located inside the wood. For coaxal line, the opposition per unit length is given by:
( 4.1 )
a = radius of interior music director
B = radius of outer carry oning cylinder
= tegument deepness of the music director
= electrical conduction
The tegument deepness can be written as below:
( 4.2 )
The equations in ( 4.1 ) and ( 4.2 ) can be matched with forest denseness which contributes the extension loss in the forest theoretical account. In this instance, parametric quantity “ a ” which denotes the interior music director radius can be replaced with conveying antenna tallness piece B as having aerial tallness. In general, non-ferromagnetic substances have permeableness about equal to, which is 1.0. From the above equations can be derives that conduction and loss per unit length as:
( 4.3 )
By replacing the equation ( 4.1 ) into ( 4.3 ) , the relationship between forest denseness and fading can be derived as:
[ Nepers/m ] ( 4.4 )
By showing it in dB/m, the equation as below:
[ dB/m ] ( 4.5 )
In equation ( 4.5 ) , the parametric quantity Zo acts as rectifying factor in finding the forest entire loss due to other flora factor such as conduction and permittivity of different types of trees, parasite consequence and temperature facet of the forest. This parametric quantity will find the different forest feature when surveies are done on different types of wood.
Relationship of aerial tallness addition factor and fading loss in wood
Tamir stated the height addition consequence in his slab theoretical account. Tamir ‘s theoretical account yields a simple account between the tallness of aerials and fading loss in wood. He expressed the dependance of field strength, EL on the aerial tallness by exponential of – is given at ( 4.6 ) .
( 4.6 )
( 4.7 )
is the exponential fading factor produced by presence of flora
S is the antenna lift
is the distance fluctuation of wireless moving ridge
N is the complex refractive index
In transmittal line theoretical account, the induction per unit length can be derived from magnetic flux as below.
( 4.8 )
B is the field itself. Which can denoted as:
( 4.9 )
Where I is the current flowing through the interior music director out, the country component will be rectangle and perpendicular to the two music directors, therefore district attorney becomes 1.dr. By replacing ( 4.9 ) into ( 4.8 ) , the equation of induction per unit length can be yield as follow:
( 4.10 )
a and B denoted as transmission and having antenna tallness. When high frequence moving ridge is transmitted, skin consequence, propinquity consequence and radiation loss consequence will do a decrease in induction per unit length.
From ( 4.10 ) , it can be derive the addition factor equation as ( 4.11 ) . When the aerial tallness is increased, the addition will increase besides.
( 4.11 )
Therefore the aerial tallness addition is related to attenuation loss:
( 4.12 )
Lapp as subdivision 4.5, a and B are the transmission and having antenna tallness. By replacing ( 4.10 ) into ( 4.12 ) , the concluding fading loss can be denoted as:
( 4.13 )
By expressed it in the unit of dubnium per metre, the equation becomes:
[ dB/m ] ( 4.14 )
Relationship of Antenna Separation Distance and Attenuation Loss in Forest Environment
In Burrow ‘s theoretical account, he mentioned the standard field is reciprocally relative to the square of antenna distance. Therefore, the fading in wood is closely related to antenna separation. Mentioning to Tamir ‘s analysis, he stated the fluctuation of the sidelong moving ridge with distance is in the signifier where P denotes as antenna distance and EL is the dependance field strength. Such a distance dependance produces a way loss which is greater than that of a geometric-optical fluctuation of, but the larger loss is expected since the sidelong moving ridge is basically a diffracted field.
In coaxal line, the parametric quantity of electrical capacity per unit length can be matched with the feature of distance loss in the wood environment. Since a coaxial overseas telegram has two separate music directors, the electrical capacity per unit length equation can be outputs from the difference in possible between the two music directors.
( 4.15 )
The equation of electric field ( E ) can be written as:
( 4.16 )
By replace ( 4.16 ) into ( 4.15 ) , the electrical capacity per unit length can be expressed as below, since electrical capacity is equal to entire charge over electromotive force.
[ F/m ] ( 4.17 )
Permittivity of music directors
outer radius of coaxal line
interior radius of coaxal line
In this paper, the permittivity of value is taken from dry wood which is equal to 1.5. Besides that, Tamir [ 1 ] besides puting the scope of permittivity with minimal value peers to 1.01 and maximal peers to 1.5. Capacitance per unit length depends chiefly on dielectric invariable of the insulating medium and music director geometry. In equation ( 4.17 ) , when the radius of outer music director additions, the electrical capacity per unit length will diminish. Since the radius of interior music director is much smaller than radius of outer music director, an premise is made to fit with forest feature that antennas separation is much larger than trees separation. The relationship between loss factor due to antennas distance and electrical capacity per unit length can be expressed as:
( 4.18 )
Substituting the equation ( 4.17 ) to ( 4.18 ) , the concluding equation is:
( 4.19 )
[ dB/m ] ( 4.20 )
Relationship of Antenna Location and Attenuation Loss in Forest Environment
In a four superimposed anisotropic forest, the electric Fieldss excited by an inclined electric dipole embedded inside the forest are obtained at the having points located either inside the forest or outside the flora. In the paper, we will concentrate in the aerials are placed inside the forest merely. A wireless moving ridge propagating within the wood may dwell of three constituents, quasi-direct moving ridge, multiply reflected moving ridge and sidelong moving ridge. Lateral moving ridge which propagate along the trunk-canopy or ground-trunk interfaces do non lend much to the entire electric field because the forest beds are lossy media. Since the aerials are placed inside the forest theoretical account, sidelong moving ridge which propagate along the upper side of the air-canopy interface plays an of import function in lending to the overall moving ridges as the distance becomes big.
In coaxal overseas telegram, conductance per unit length is given as below:
[ S/m ] ( 4.21 )
The shunt conductance is normally really little because dielectrics with good insulator belongingss are used. At high frequences, a insulator can hold a important resistive loss. Dielectric loss consequence is the dielectric losingss result from escape currents through the dielectric stuff. This causes an addition in the shunt conductance per unit length and produces signal fading. The relationship of conductance and opposition is related by:
( 4.22 )
Equation ( 4.3 ) shows the relationship between conduction and the opposition loss per unit length. Since the equation in ( 4.22 ) is inversely relative, it can be reasoning that:
( 4.23 )
The concluding fading loss equation is expressed as:
( 4.24 )
[ dB/m ] ( 4.25 )
Concluding Equation of Forest Model
Coaxial overseas telegram is used as a transmittal line for wireless frequence signals, in applications such as linking wireless senders and receiving systems with their aerials, computing machine web connexions and administering overseas telegram telecasting signals. However, opposition per unit length, induction per unit length, electrical capacity per unit length and conductance per unit length, these four constituents contributes the major losingss when a signal is go through coaxal overseas telegram. In this paper, it is shown that feature of coaxal overseas telegram can be match with characteristic of forest environment to happen the losingss in an easier manner by extinguishing the complicated mathematical computations. The entire loss equation is the summing of extension loss on forest due to factors of forest denseness, antenna height-gain consequence, antennas separation and antennas location.
( 4.26 )
= loss factor due to forest denseness
= loss factor due to antenna height-gain consequence
= loss factor due to antenna distance
= loss factor due to antenna location
RESULT AND DISCUSSION
Comparison between Propose theoretical account and Simulated informations by Tamir ‘s Model, ITU- R+Plane Earth
In this subdivision, in order to verify the propose theoretical account that able to calculate the way loss anticipation informations accurately within 200MHz, there is needed to do comparing between 2 other forest way loss anticipation theoretical account which are Li et Al ‘s theoretical account and FITU-R+Plane Earth theoretical account [ 3 ] . When 1967, Tamir [ 3 ] proposed a half-space theoretical account to cover with wireless moving ridge ( 1-100 MHz ) extension in the wood and explained the associated phenomenon dominated by a sidelong moving ridge manner of extension. Furthermore, he [ 4 ] continued his survey on the extension in forested environment to the dissipative insulator slab theoretical account to account for the land consequence on wireless moving ridge ( 2-200 MHz ) extension. Besides, Li et Al. [ 5 ] , [ 4 ] performed an extended survey of the four-layered theoretical account with the sidelong moving ridge manner of extension in anisotropic woods utilizing dyadic Green ‘s maps.
Figure3.1. Comparison between Propose theoretical account and
simulated informations by Li et Al, FITU-R+Plane Earth
The experimental information is no plenty in the deep wood which over 1000m of deepness of leaf, therefore the propose theoretical account is force to compared with the analytical consequences that reported by Li et Al. [ 6 ] utilizing the numerical simulation method. Besides, FITU-R+Plane Earth is the upgrade theoretical account of ITU-R [ 3 ] which is derived from a set of informations measured up to 20GHz in uniformly distributed plantations where the trees are every bit spaced and with really small or no underbrush. The propose theoretical account have assume transmit aerial height a ( Htx ) equal to 5m and receive aerial tallness B ( Hrx ) equal to 10m severally, while the deepness of leaf is fixed to be 5km. Then the propose theoretical account followed the simulated informations and presented as Fig. 3.1.
The Fig. 3.1 shows that Simulated by Li EL Al. have somewhat lower way losingss compare with proposed theoretical account and FITU-R-Earth plane, while proposed theoretical account is better than the FITU-R-Earth plane. Besides, it can be observed that propose theoretical account is near to the numerically simulated consequences by Liet Al. This because the simulation has taken into consideration the sidelong moving ridge parts, particularly when at larger leaf deepness when both the sender and the receiving system where placed inside the wood. The sidelong moving ridge travels largely in the lossless air part and becomes dominant at comparatively big leaf deepness. Therefore FITU-R theoretical account show hapless anticipation truth is caused by without consider sidelong moving ridge part.
The propose theoretical account is found to be good theoretical account for the anticipation of foliage loss over a big leaf deepness which up to 5km at UHF set for the land forested readio moving ridge extension. It can be verified for the frequencires from 250MHz to 1000MHz. Furthermore, it can be assumed that as the equation calculation point, propose theoretical account is extremely simplified comparison to this 2 theoretical accounts, therefore this show good pontential for expertness to cut down the clip calculation when predict the way loss in wood.
Comparison Between Dyadic Green ‘s Function and Proposed Model
From Fig 3.2, there is some betterment from the Fig3.1. The FITU-R theoretical account is limited to the lower frequences which merely can up to 1000MHz. In order to turn out that the propose theoretical account is able to foretell the losingss up to UHF set frequence which up to 2000MHz, there is needed to compare it with Dyadic Green ‘s Funtions by Li [ 6 ] .
By adding the four constituents, opposition per unit length, induction per unit length, electrical capacity per unit length and conductance per unit length, the entire loss for propose theoretical account are computed. The wood is considered to be with a tallness of 30m, and canopy and bole to be 10 and 15 m high, severally. Transmit and receive aerial highs, Htx and Hrx used in both theoretical accounts are 5m and 10m severally. Beside the deepness of leaf is assumed to be 1000m, it because to ansured the anticipation truth from Li ‘s theoretical account [ 6 ] .The comparative permeableness is taken at = 1 and the denseness would be 0.6. The conduction is the opposite of denseness, which is equal to 1.7.
Figure3.2. Comparison between Dyadic Green ‘s Function and Proposed Model
The graph can be observed that the propose theoretical account is presented closely to the Dyadic Green ‘s Funtions by Li. Thus it is proved that the proposed theoretical account able to foretell the losingss at deepness of leaf 10km at UHF set which from 1MHz up to 2000MHz. Although the propose theoretical account showed rather high way loss at 1500MHz to 2000MHz, it is still considered at acceptable phase in the wood environment. It can be assumed that as the communicating point approaches the treetop degree, the truth will worsen, because there will be more part by the sidelong moving ridge as reported in [ 6 ] .
In a transmittal line theoretical account, it has been proven theoretically that at higher frequence the accomplishment of loss factor in transmittal line due to resistance per unit length induction per unit length, electrical capacity per unit length and conductance per unit length, all will go higher. Thus the propose theoretical account and Dydic Green ‘s Function are presented overall accurate anticipation of way loss, particularly from 1MHz to 1500MHZ.
However, the most important point here is the manner of the propose theoretical account presented good pontential and can be used easy by users who making research of way loss anticipation in wood.
Loss Dependence on Antenna Distance
Relationship between way loss invariable and aerial distance
The basic transmittal loss in forest frequently involved the parametric quantity of antenna separation. For the same wood environment, the relationship between the way loss and the antenna separation are investigated.
Figure3.3. Relationship between way loss invariable and aerial distance
Figure 3.3 shows the consequence of antenna separation to the way loss invariable. It can be observed that the fading loss in forest medium is straight relative to the antenna separation in metre. This relationship is verified by Tamir in the survey of fluctuation of wireless moving ridge with distance [ 3 ] . The aerial scope is consider from 1 metre up to 10000 metres as those evaluated by Tamir in the full frequence scope of 1 to 100MHz. However, from the measurement study submit by Jansky and Bailey [ 8 ] , the geometric loss was obtained up to 32 kilometres even though the terrain was really irregular.
Comparison between Proposed Model, ITU-R, FITU-R and Cost235 Models at 2000MHz
In this subdivision, in order to turn out the propose theoretical account is functional with the anticipation of loss addiction of antenna distance, it is necessary to compare the propose theoretical account with other theoretical accounts.
The Cost235 theoretical account [ 3 ] and FITU-R theoretical account [ 5 ] , there are merely the in-leaf leaf theoretical accounts are used, because the tropical plantation under consideration is an evergreen [ 6 ] . Experimental informations collected from the ITU-R theoretical accounts, since FITU-R theoretical account and Cost235 theoretical account are modified from the ITU-R, therefore it is more convenient to be the experimental information and the truth will be ensured. The frequence to be used is 2GHz, since COST234 theoretical account is optimized from the measured informations at milimeter moving ridges ( up to 57.6GHz ) , which consequences in a higher predicted way loss at UHF [ 5 ] . Besides, ITU-R and FITU-R are both derived from measured informations taken at frequences ( up to 20GHz ) [ 5 ] . Therefore there are suited to be taking as the theoretical account to be compared.
Figure3.4. Comparison between Proposed Model, ITU-R, FITU-R and Cost235 Models
From Fig 3.4, it can be observed when the leaf deepness additions, the ability to foretell the way loss by the Cost235 theoretical account and ITU-R theoretical account become hapless. Contrary, the propose theoretical account shows really good predict ablility if comparison to other 3 theoretical accounts since it is the closest theoretical account to the experimental information. Besides, the Cost235 shows high fading from 100m to 10km, while the propose theoretical account provide mean low fading if comparison to other 3 theoretical accounts. This once more proved that propose theoretical account is more accurately. When the leaf deepness & lt ; 400m, ITU-R theoretical account, FITU-R theoretical account and propose theoretical account are located at the really stable phase if comparison to Cost235 theoretical account. There are shows about equal to each other, therefore this guarantee that the propose informations is accurate in the little deepness phase.
Loss Dependence on Antenna Height Gain Factor
In this subdivision, the loss dependece on aerial height addition factor is examined. Using the same forest environment profiles, the having aerial tallness, Hrx is adjusted in this analysis to verify its relationship to the forest loss. Furthermore, there is no direct comparing informations found in the Dyadic Green ‘s map. The loss dependance on aerial height addition factor is examined between proposed informations and the FITU-R-Earth Plane [ 5 ] [ 9 ] . The frequence 2000MHz is used to propagate through the forest theoretical account. In present survey, the tallness addition factor is found related to inductance per unit length parametric quantity in the coaxal line.
Figure3.5. Comparison between Proposed Model and FITU-R+Plane Earth
Figure 3.5 show the relationship of receiving system tallness and fading loss. In the proposed theoretical account, merely receiving system tallness will be alteration and the sender tallness will be fixed as mentioned earlier. From the informations, low fading can be achieved by maintain the antenna same tallness or higher than the tree when propagate in the wood. This fading loss due to receiver tallness was foremost analyzed by Tewari [ 10 ] , who performed an in-depth empirical mold of antenna height-gain on the way loss in the wood. The concluding consequence proven that the fading loss is so dependent on the receiving aerial tallness. The larger height value will gives smaller fading loss when moving ridge propagates through the wood.
Loss Dependence on Antenna Location
In this subdivision, the Li et Al. [ 6 ] experiment informations is used, since it able to back up UHF which up to 2000MHz. The 2nd experimental information is usage from the propose theoretical account which same with the ITU-R theoretical account [ 5 ] that used at Fig 3.4, the frequence is 500MHz.
Figure3.6. Comparison between Proposed Model and FITU-R Model with
Li et Al. Experimental information.
From Fig. 3.6, it can be observed that the propose theoretical account shows good anticipation truth as compared to LITU-R with perfect plane Earth that proved from the comparings and analysis made from [ 11 ] . Besides, if compared to the predicted consequences by ITU-R theoretical account with perfect program earth theoretical account, the truth of the propose theoretical account is significantly good and progressively at big leaf deepnesss. Obviously, the experimental with 500MHz shows less fading if comparison to the experimental information with 2000MHz, it is due to the frequence proportional to the way loss ( fading ) , which mean that if the larger frequence, the larger path loss to be occurred.
As decision, a way loss anticipation in forest theoretical account is developed to foretell the way losingss during the wireless moving ridge extension in forest environment. The propose theoretical account is builted based on the transmittal line theoretical account with lumped elements including of opposition per unit length, induction per unit length and electrical capacity per unit length. Besides, the frequence ranges able to back up the theoretical account is from 1MHz up to 2000MHz.
Every parametric quantity from the lumped elements can be stand foring for different forest parametric quantities. The opposition per unit length parametric quantity is used to foretell the fading loss due to forest denseness, while induction per unit length is used to foretell the fading loss due to antenna height addition consequence and electrical capacity per unit length is used to foretell the fading loss due to antenna distance. At the terminal, the concluding theoretical account sum up the entire loss contributes by those lumped elements and the losingss equation for the forest theoretical account is presented.
From the consequence proven, the propose theoretical account is found to be good theoretical account for the anticipation of foliage loss over a big leaf deepness which up to 5km at UHF set for the land forested wireless moving ridge extension. It can be verified from Fig 3.1. Furthermore, it can be assumed that as the equation calculation point, propose theoretical account is extremely simplified, therefore it have really good pontential for expertness to cut down the clip calculation when predict the way loss in wood. Besides, the Fig 3.2 proved that the propose theoretical account presented closely consequence as comparison to the celebrated Dydic Green ‘s Function by Li ‘s theoretical account. On top of that, the Fig 3.3 shows that the fading loss in forest medium is straight relative to the antenna separation in metre therefore turn out that the equation of electrical capacity per unit length from lump elements is verified.
From the consequences, all are proven that the transimission line parametric quantities can be direct derived and fit to the forest chracteristic. Thus the propose theoretical account can be consider as one of the new way loss theoretical account that help to inverstigating the wireless extension in forest environment.