![]() ![]() Povernei), Bucharest, Bucharest Police Station Dorobani 1 tip 2. If you use our services on or after August 20, 2020, you will have accepted our new policies. Our Consumer Services Privacy Policy and Enterprise Services Privacy Policy will become effective on August 20, 2020. ![]() 20, Bucharest, Bucharest Police Station Giurgiului No tips or reviews 25. Please click the link in the email to confirm your subscription OK Subscriptions powered by Strikingly.īazaltului nr. POLIIA BUCURETI SECIA 11, Sector 3, BUCURETI. Sectia 4 politie iasi adresa 11 politie evidenta populatiei program sectia 9.Ĭontacteaz-ne. sectia 13 politie program eliberare buletine, sectia 11 politie program eliberare buletine, sectia 14 politie program eliberare buletine, sectia 12. The antenna efficiency is the parameter which highlights how much of the current power is transformed into wave power.Aproximativ 204 pentru program lucru eliberari buletine bucuresti.Įliberare Cazier Judiciar Bucuresti Sector 4 -Huge Selection - Rent or. By substituting equation (4) into (5) yields: 2 30 R d f d 2, sin (6) 0 0 An antenna must be constructed in such a way that most of the high frequency power is converted into power radio waves. Mathematically, the value of this resistance can be expressed by the formula: 2P R 2 I (5) where I represents the current amplitude from the antenna terminals. ![]() In practice, for many antennas, the radiated electric field expression is: E 60I r f, (3) If we consider η=120π (in vacuum or dry air), then by substituting the equation (3) in the expression (1), we obtain, 2 15I P d f d 0 0 2 2, sin (4) The radiation power has a dynamic factor, allowing the antenna to be characterized by a fictitious resistance called radiation resistance. 2 2 E r P d f d 2 0 0 2 m 2, sin (1) Where r,, θ are spherical coordinates, and (2) is the intrinsic impedance of the environment. To determine the radiation power, the antenna is considered to be placed in the center of a sphere of a given radius (r). The radiation power of an antenna can be determined by calculation, if the expression of the electric field radiated by it is known. For the radio facilities with special designations, the antenna must provide a certain form of the directivity. Without knowing this parameter, it is impossible to establish the nature of the radio connections that are possible with a given device. The radiation pattern of an antenna represents one of its most important parameters. The parameters that characterize the essential properties of antennas are the radiation pattern, directivity factor, gain, wavelength own working range, frequency characteristic and the polarization performance. The parameters that relate to the main function of an antenna are: radiation power, radiation resistance, loss resistance, yield, maximum voltage, effective height, the effective area, the antenna aperture, utilization coefficient of the antenna aperture etc. The main function of an antenna is to convert high frequency energy in electromagnetic waves (for emission) and vice versa (for reception). They function property only in the emission or reception facility for which they were designed. ANTENNA PARAMETERS Antennas are devices that are part of a complex of radio facilities closely related to the other subcomponents of the ensemble. Keywords: Impedance, SWR, antenna gain, radiation pattern. Practical measurements on models without adaptation circuits have confirmed that variants considered are functional. These conditions have led to providing practical solutions to adjust antennas in order to achieve maximum efficiency in operation. A second simulation was aimed at highlighting the antenna parameters by imposing the condition of Z = 50Ω impedance. The simulations for antennas with specified dimensions were first made by fixing a value of 1:1 SWR, the other parameters of antennas being the result of this condition. For these exercises I used the MMANA-GAL program design and the miniVNA analyzer to highlight practical results. In this article I described the main parameters of antennas, I simulated and practically verified the behavior of two antennas for the VHF range. GHEORGHE Tehnical University “Gheorghe Asachi” of Iasi - Faculty of Electronics, Telecommunication and Information Tehnology, Bd. 1 (18) PERFORMANCE BENCHMARKING FOR J-POLE AND OMEGA ANTENNAS USED IN VHF AREAS Eng. ISSN 1843-6188 Scientific Bulletin of the Electrical Engineering Faculty – Year 12 No. ![]()
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